1:23 i cannot un-imagine Jason just basically whipping out his whiteboard then lecturing the bear on engineering.

@wiciuwiciu2783

2 жыл бұрын

I bet it was about BEARings he he he he

Being a casual mechanical hobbyist, I never really thought about the parallel oil provides to an engine's health as blood does to a person's health. Great video, as always, sir.

I'm a former chopper pilot from the French Navy. I remember we did *a lot* of oil analysis for gas turbines. They were pretty helpful to know if the engines were fine of if they were gonna eat their internals. =)

Hi Jason, retired mechanical engineer here, you should teach to local universities - you are presenting the common applications of engineering science (most important for consumers' knowledge). Back in the 70's it took me a one year internship at Ford to learn about "practical" applications of some (if not all) of the theoretical knowledge I had learned at my University. You make it interesting and your enthusiasm explaining engineering principles is contagious. Thank you for these great presentations, Ciao L

I've been using Blackstone for a few years to keep tabs on my vehicles. I can concur with the more personal analysis they include in each report, with an atta boy or two thrown in for a good report. Lol. It's a nice touch with what would usually be a dry read.

@stephenmoxley3004

2 жыл бұрын

I totally agree. I've been using them for a number of years and find their service to be very informative and valuable.

@jons4686

2 жыл бұрын

I came to the comments to say Blackstone. Totally agree

@HazewinDog

2 жыл бұрын

what does such an oil analysis cost?

@jons4686

2 жыл бұрын

@@HazewinDog 30 dollars a Blackstone. They'll ship you the sample kits for free. It's amazing what you can learn about your engine and oil

@MrMikey1273

2 жыл бұрын

@@jons4686 $30 definitely worth doing once a year on a vehicle that you plan to keep long term. I did that for my Jeep Liberty CRD for 10 years and already started with the first oil change on my 2020 Tacoma.

11:46 - Hmm, not sure I trust the third party if they said no oil showed up in your oil samples. 🤪 (just joking, it was supposed to say water)

@EngineeringExplained

2 жыл бұрын

Wow, great catch, yes, it's supposed to say water! 🤦‍♂️😂

man these videos are truly the best on youtube, I don't think enough people appreciate the work that goes into these

@EngineeringExplained

2 жыл бұрын

It was a lot of work to put together, and fascinating information - thanks for watching!

@tranktrunk1641

2 жыл бұрын

Its all personal opinion tbh, In my opinion GreenHamGaming has the best content on youtube.

Blackstone is great! I love how personal the descriptions of the results are. They liked my name for my Kioti tractor, which I mainly use to mow fields: Mow-Bi Wan Kioti. Unfortunately, that old, formerly abused machine more or less makes Blackstone's people say "yikes!".

@mr.e8543

2 жыл бұрын

true im also using them for my e85 engines tests on my channel . they show great care always

Did you just include your vacation expenses as a tax write off? You're a genious, Jason. Great video BTW.

Great video! Didn't think oil analysis would be that interesting. Seriously what a good dude for putting this info out there for all of us.

After several years of being a mechanic, I am still shocked and amazed when a vehicle comes in with "most" of its oil. Almost all are waaay overdue, low or almost none. Trying to explain to someone about oil consumption "but it doesn't smoke and I was told to change my oil when the "light" comes on"......

@kristianhermann5971

2 жыл бұрын

That's scary. Used car buyer beware.

@mikeschultz6383

2 жыл бұрын

Sounds like most are women who are single and no one is telling em too change there oil lol.

@MrAPCProductions

2 жыл бұрын

@@mikeschultz6383 of the hundreds of vehicles I see a year most of them are owned by men. Age is 35+ for more than 80% of my customers. Almost zero percent are owned by young women or single women.

@mikeschultz6383

2 жыл бұрын

@@MrAPCProductions very interesting so i guess don’t go off the assumption that women don’t know anything about cars and there maintenance nice too know. Also good too hear

@blahorgaslisk7763

2 жыл бұрын

@@mikeschultz6383 I think the reason is that the vast majority of car owners are not interested in cars as anything but transportation devices or to a degree as a status symbol. The inner workings are not what interests these people. It also says a lot about how reliable cars has become. It used to be that you more or less had to know a bit about how the car worked as they tended to break down now and then. Just look at something as simple as oil leaks. If you look back forty or fifty years there would be an oil slick under a lot of cars. It was just the way things were. Today it's really uncommon to see this and when you discover one under your car you will react by wondering what has gone wrong. I've also thought of the number of cars I see having broken down on the highway and standing on the shoulder waiting for assistance. When I was a kid you saw this every time you drove for any distance on the highway. Today it's really uncommon to see anything worse than some one who ran out of gas, and even that is uncommon and fuel gages are usually a lot more reliable today than they used to be. Remember when cold starting a car could be an adventure? Remember using the manual choke, pumping the gas pedal, or perhaps having to use starter fluid if it was freezing? I have almost forgot all of that. My twenty year old Toyota has never had a problem starting even when it was really cold. Cars has become so easy to use that people are forgetting how they work. And when something goes wrong most people just leave it to a mechanic to fix. The only time they care about what makes their car run is when they pay the mechanic for taking care of their car. Heck I have friends who never open the hood unless they are forced to do so. They have a mechanic service it once a year, and just assume that they will take care of things like oil changes, air filters, thread depth, coolant levels and so on. I can safely say they have no idea about oil change intervals or anything else. All they do is fill it up with gas and drive.

I think this way of oil analysis response is to make it more accessible and understanding to the avarage driver. I think that is actually pretty good. Also shows that there is most likely a human actually writing that.

The oil analysis shows what many Subaru Turbo owners have been saying for years. Mobil 1 thins out way to fast. At 12:35 in the video, the answer to why the viscosity dropped was you used Mobil 1. :)

I have used Blackstone on all of my cars for several years now. The information they provide is invaluable. It’s reassuring to KNOW what my engines and oil are doing versus just changing oil blindly.

I’ve been monitoring my engine oil with Blackstone since 0 miles. Good way to know what’s going on with your engine.

Please repeat at 6k, 9k, etc: as much as you will alow on the mighty croastreck. Thank you.

Absolutely amazing video! Thanks for the post!

Didn't know this was a thing. Just ordered two kits to get my rigs checked out. Thank you!

Fantastic job making oil analysis into an interesting video. Thanks as always.

I remember arguing about an early oil change with the service lady at Ford. She was convinced it was pointless.

@cslim117

2 жыл бұрын

Same at my Honda dealership. I change my oil every 5,000 full synthetic and the service manager said “that’s pointless it can go 10,000 miles”.

@JohnS-il1dr

2 жыл бұрын

Those ford ecoboost engines need early oil changes as the deposits build up quickly. Ford Boss Me channel did several vids on this.

@cruise2kx

2 жыл бұрын

@@JohnS-il1dr now that is interesting.

This is probably one of the most informative videos on engine oil I've ever seen. Well done, m8

Nicely done. Thanks for the video.

this was really cool to learn that you could gain so much insight just from analyzing the oil

I literally clicked on this because I’m leaving from LA to Yellowstone and little did I know you did the same trip.

I think it's great that you did a video about this. Yes oil analysis' are often not cheap, but they can well be worth the money. My last oil analysis predicted a head gasket failure well ahead of the gasket failing catastrophically. Could have been a lot more expensive hadn't I done the analysis and not knowm about it.

I'm doing an oil analysis on my own vehicle later this week when I change the oil. The video was really informative on the metrics to watch out for for my engine health. Thanks Jason.

I’ve been testing oil for 30 years. Running oil analysis for my trucking fleet. No one absolutely no one beats amsoil.

Keep them coming.. as they are Informative

A fascinating idea for diagnostics. I am reminded of all the CR-V 1.5 turbo engine videos claiming fuel-oil dilution. I got rid of my 2017 though.

As always, ,great content and info.

Thanks for sharing, good stuff

Great video👍really interesting, I used to work in an open cast mine as a welder. They took oil samples from all the machines every couple of weeks (engines, gearboxes and final drives). I always wondered how they analysed it. Thanks👍

Always enjoy Blackstone oil reports. It's also nice that they respond to any questions or concerns that I may write in.

This is highly informative and very educatiomal, thanks a lot Jason!

@CRVB7

2 жыл бұрын

No, it is not educatiomal at all.

Very interesting video! I recently learned about oil analysis at my new job, we operate a big turbine compressor that compresses chlorine and I take samples of the oil every month to get it checked for wear and possible chlorine leaks. These measurements realy can tell you a lot.

You did an excellent job presenting this information! Well Done.

@EngineeringExplained

2 жыл бұрын

Thanks!

I've ordered and recieved a Blackstone analysis kit and plan on a 3k change on my 2.4 DIT. About 600 miles to go. I feel this is a very important subject and have since the 70s and 80s while working as a heavy equipment operator and saw oil samples taken every oil change. Thank you for posting. 👍

An excellent presentation as always. I drove an F250 7.3 for 16 years and had oil analysis at every oil change after the second one. Nothing showed up and I felt very comfortable.

well, I might change oil this year. After some years (more than I'd want to admit), my engine deserves it.

I didn't realize that such a service was available to end-users smaller than fleet operators. Interesting! Seems like a very useful service indeed, depending on the cost.

@nicktaormina4623

2 жыл бұрын

It's like $30 with Blackstone

@chloedegurechaff1941

2 жыл бұрын

Blackstone will also send you bottles for free. with free shipping back to them.

As far as mobil 1 I am quite impressed with their new GF6 oils, i’ve been running full synthetic in my 3.6 R legacy from day one, i’m currently almost at 120,000 miles and the engine barely burns any oil I just recently was able to get my hands on this new classification of oil and the oxidation rate is impressive compared to its old blend! Jason!

Excellent video thanks Jason... clear concise and very interesting. makes me happy I have decide to have my Turbo Direct injection car serviced every 7500 Kilometers since new... to make sure the carbon levels are low to minimise carbon buildup on the valves.

As always, pleasure to watch things that my professors at the university tried to explain to us, but unsuccessfully.

I'd like to see an oil analysis on a CNG (natural gas), or propane fueled engine. I have no personal experience, but anecdotal have these engines running very clean with very little sludge and soot. Edit: I wonder if this is how oil manufacturers come up with such long change intervals?

@ohioplayer-bl9em

2 жыл бұрын

I worked at a gas station that had a huge propane tank with a pump next to the interstate in the 90s. We would get people that needed to fill their vans (mostly vans for some reason) with propane. Often they would check their oil and I would check it out with them. The oil always looked brand new. As a side note my car is E85 and being in Ohio its readily available. If I run mainly E85 my oil seems to stay much cleaner than when using gasoline.

@trackpackgt877

Жыл бұрын

You know I always wondered the same thing because I have a propane (dual fuel) powered generator and I wondered if the propane was easier on the oil than gasoline. Ohio player1177 thanks for the info also I appreciate it

This video is timely for me as I'm about to send a sample to Blackstone for the first time ever. Just waiting to rack up 3,000 miles on this batch of oil and get a check-up on the trusty '92 Ford.

I was lucky enough to hear about blackstone before I bought my first new car 15 years ago. Since I do all my work myself, its good to be able to catch something early enough to do something about it. Blackstone is great!

Now we need an experiment for transmission oil. Great video 👍

Hi Engineering Explained, I wanted to know if you plan on posting the second part (off-road) review of the new Ford Bronco? Would love to hear your input on that, as it's the main attraction for me if I were to purchase that type of vehicle! Thank you so much for your hard work, long time subscriber, long live the white board!

Hey... That's a great video quite informative... The reason why the results showed high level of fuel in the 15min idling is for a reason explained below. Piston rings and compression rings have a small gap which expands once the engine is warm enough.. till is was warm enough your vehicle had a the addition of fuel to the oil... I hope this information helps you and others reading this... Thanks

Nice video. It's very instructive. But there's one topic I would like to hear about, and it's why some fluids cannot be mixed? I'm thinking especially of coolant fluid or hydraulic fluid, like transmission oil. There's different kind of these fluid and they can cause damage if they're mixed together. Could you make something about this?

Interesting, thanks.

Hey - thanks for all the awesome videos! I thought it might be cool if you made a video about engines at the extreme end of car engineering (for example, semi trucks and/or monster trucks). Or maybe you already made those?

Thanks for the great topic Jason and your interesting and informative presentation. One possibility that I'd suggest you consider for the reason for the hot temperature viscosity drop is the action of any kind of complex valve timing adjustment system that might be using oil pressure to actuate the mechanism. With high contact pressures and local temperatures in these mechanisms, you could be having the oil's VI additives being sheared down. I had this happening on the VQ37VHR engine in my 370Z using the recommended Nissan ester oil. I looked at a number of used oil analyses of this engine in 370Zs and G37s with this oil and saw a consistent drop in viscosity from 5W-30 to about a 5W-20 after about 3K miles. The recommended oil change interval(OCI) for this oil in this engine is 3750 miles, and so that informed my decision to go with 3K mile OCIs on my car. The oil temperature on this engine runs characteristically high, the consensus opinion being because of the VVEL mechanism, and so it's just an inherent property of the beast. You may be having a similar situation with your car if everything else is okay and so you may just have to live with shortened oil change intervals if you want to maintain proper hot viscosity. One consideration might be the use of one of those synthetic base stock group V esters that don't need as much VI improvers added to achieve the desired hot temperature viscosity levels. The problem with them is their cost and it might just be cheaper to go with the less expensive synthetics and just change them more often.

I used to send in oil analysis. All it seemed to do was determine and confirm what you already knew. When a motor isn't happy they usually let you know it other then that not worth losing sleep over common wear.

Regarding extended performance oils it’s hard to beat Mobil 1 EP. The other which has many certs is Castrol extended performance(gold bottle). Both some truly amazing lubricants! Great job!

Good info! So when do you do your first oil change on a new car? I do mine at 1000, to me that's when an engine is broken in and ready to go!

Had a bad analysis on an old boat engine. Still ran and performed like a champ.

Well done... I have used Blackstone labs for years.

Great video! Really enjoy all of your work. Side note: may want to look into a Fumoto valve; I have a BRZ and oil changes are much easier (and cleaner) when not dealing with the drain plug and washer, plus you can take quick samples without needing cleanup of a pump after. Need to install one on our CX5 but I have way too many washers left to justify it yet.

@lumberjackdreamer6267

Жыл бұрын

What about oil extractors? What’s your opinion on them?

As always great content

Yes, I use Blackstone (have for many years) and they are both competent and lightheartedly friendly.

Kudos for taking samples for separate analysis

Awesome video

I use blackstone for oil analysis with my vehicles, I love the comments I get back from them!

I got a new car this year, and was a bit surprised when I looked into the owner's manual that it recommended the first oil change at 12 months or 6,000 miles. I did a double-take. IIRC, coolant flush was either 100 or 120k miles. It's amazing what these engineers have done.

Very helpful!

I use BSL yes I always enjoy the commentary.

Nice job! We are big believers in used oil analysis. Higher levels of blow-by will increase oxidation, soot and fuel dilution, so used oil analysis is a great tool for checking and monitoring piston ring seal.

People like you make America great!

would you consider talking about oil burning? you've enrich our minds with lots of useful engine oil topics, thanks man.

Decades ago when my brother was a diesel truck mechanic, he told me about oil analysis as a way to determine an engine's health. When it comes to hidden engine damage, I wonder how the VW air-cooled flat-four in the 1960s would rate? Having operating such vehicles, it's remarkable the amount of maintenance neglect that engine could be subjected to, and still keep running.

Jason, another informative video on hot button topics of motor forums. No comment pro or con regarding oil analysis on passenger cars.

Great explanation of UOA. Why I really like your channel, it's SCIENCE based. NOT as so many are, opinion based. Well done.

Hi, great video. BTW, what was the mileage of your Subaru at the beginning of the test? Thanks!

Good stuff. On a new engine, what mileage do you recommend for the first oil change?

Great vid and very informative, thanks a lot. I've never heard of engine oil analysis other than at the engine plants and specialised engine remanufacturers. Where would I find such an oil test performed and what's typical cost?

@tangydiesel1886

2 жыл бұрын

They can run about $25-$40 per test. Blackstone was the third party. About all major oil manufacturers offer an oil test as well.

A fascinating video, can’t wait to run this test on my Tesla

I’ve honestly been waiting for this video forever haha. I saved a couple oil samples from my first car, 98 dodge stratus, and really wanted to send it in, but had to move. My prelude will certainly have some interesting results.

@nicolaasvandenberg4023

2 жыл бұрын

would be cool to know

@ZonymaUnltd.

2 жыл бұрын

@@nicolaasvandenberg4023 - I certainly intend to use their services, I'll do the lubricant analysis as soon as I can 👍🏼

I love Blackstone labs with their oil reports I've been able to specifically try different oils in my vehicles and see what oil produces the least wear metals mobil 1 does phenomenal its a great oil and I was always a lifelong mobil one guy but Amsoil edges them out just a bit in wear metels TBN and oil life!!!!! Either way great oils mobil 1 and amsoil is the only oils i trust in my vehicles power equipment motorcycles ect....thank you Blackstone!! Great video brother

You took so many samples it must have been close to a full oil change!

Can you make a detailed video on specifically why alternators go bad (failure mode analysis) as well as the symptoms that said failures produce? Practical information such as the “why” behind the “what” is typically very interesting to most people.

This is really interesting, I would love to see a fourth column from samples of the same oil taken at the next oil change to see just how much it changed. Also it would be really interesting to see a similar test done on an older engine with lots of miles on it perhaps paired with additional data such as cylinder compression, fuel trim etc. just to see if you can draw any conclusions from them.

lol. Took extra samples just in case Mobil1 was lying. I like that dedication.

Interesting addition re sand... I used to work with dual fuel diesel engines that would run on mixture of diesel and CNG or LNG. The attraction for many was to use Biogas/Biomethane for the CO2 benefits. We found that this kind of gas had siloxanes in it. Overtime it would basically be sandblasting the insides of the gas injectors and getting into the engine oil etc. Not good! They tend to leave a white powdery residue on the hot stuff.

What's the typical price for oil annalise? Cool video thanks

I have a 16 F150 with the 2.7L Ecoboost engine. At about 75k I had a Blackstone oil analysis done. I only use Mobil 1 full synthetic 5-30 and I change it at 3-4k mile intervals. That analysis was at 3k and the only warning I got was about the viscosity as well. They informed me it may be from fuel dilution but after checking my fuel trims and injector leak down I saw nothing unusual. It's nice to see you had a similar experience and they give follow-up information on how it could just be you're changing it sooner than you need to. I was thinking since my engine is direct injected and turbocharged it may just have more blow-by than a standard vehicle engine and that could be the reason for the fuel dilution/drop in viscosity. Thanks for this video Jason, very informative.

@rogergeyer9851

2 жыл бұрын

Jed Brown: Better to change it a little too often than to have a HUGE engine rebuild bill, or decide you need a new car. From someone who likes driving reliable older cars with no car payments who considers oil changes MONEY WELL SPENT.

Dealer laughed at me when I took my 2021 tundra for its first oil change at 3k miles. And I explained to them how after the break in that there is stuff in the oil that needs to be flushed out ! Glad to see I’m not the only one

@Dcc357

2 жыл бұрын

I changed my 2021 GTI's oil at 1000 miles, then I will again soon at 5000. I did it myself since I have access to a lift at work. First oil change was supposed to be 10,000 miles or 1 year, which is insane for a turbo 4 - even if I have an iron block.

@tundras4ever552

2 жыл бұрын

@@Dcc357 10k oil changes are absurd

I love things like this. Rather than just "part breaks, replace it" instead use a service point to analyse potential issues and address weak points before they leave you standing at the side of the road with the hazards on. Both options keep the mechanic in a job, but only one causes, at minimum, huge inconvenience.

Blackstone is great, I've been sending them locomotive oil samples for years. Thanks for explaining what everything on these reports means, I was a bit lost on a couple items before. Fun fact, locomotive engine oil cannot contain zinc because it's not good for the silver bearings present in certain engines.

Great video, Jason! Finally someone provides an understandable explanation! I’ve been struggling to establish a position on my engine/oil condition, but with some confusing feedback, I wonder what your take on this would be. A BMW S63TU engine, appr 15k miles with oil changes always at 3-5k miles. 2 oil analysis (just under 10k miles - 3rd oil change, and appr. 12k miles), both returned all clear EXCEPT for fuel dilution - both times measured at 3%. BMW service advisor feedback was this is likely due “poor driver profile”, after digging into this more appears lots of short distance driving is classified this, second time this issue was definitely not a factor, but I struggled to get anything meaningful out of them, finally they responded with a strange message: 7% is considered a warning level, 10% a write-off level! Sounds bs to me, but I haven’t been able to verify this with BMW directly. Any thoughts?

@waynes.2983

2 жыл бұрын

If it is under warranty you may not want them to kniw about fuel dilution since they will say poor driver profile is a reason to deny warranty work.

Great test and video. Let's see some more oil test on the Subaru

ey! you watched Ed Bolian's impression of you in their latest cartrek? I thought it was ok, and it shows how big your channel really is when he does it. So congrats! and how's the Miata? you going to hide it from the winter or get studs and enjoy the winter with it?

Damn, I want an enthusiastic and supportive oil spec sheet. Anyway, congrats on your car's internal tolerances, they must be magnificent.

This analysis is invaluable.

@UnipornFrumm

2 жыл бұрын

Its useless if you get an electric car

@miltiadiskoutsokeras9189

2 жыл бұрын

@@UnipornFrumm It is not significant if you travel by foot also.

@UnipornFrumm

2 жыл бұрын

@@miltiadiskoutsokeras9189 yeah but you wont do that to go to another city for example

@acchaladka

2 жыл бұрын

@@UnipornFrumm completely pointless if i take Greyhound.

@mercury0214

2 жыл бұрын

@@UnipornFrumm and your electric car is useless after 125,000 when the battery dies

My report from Blackstone 2010 rx450h 77830 miles Amsoil 25000 mile Guarantee 20,078 mile oil change PAUL: For oil run more than 20,000 miles, these results are impressive. That's a lot longer than the ~7,900 miles our universal averages for these engines are based on. Iron is a bit above average, but iron naturally accumulates with miles on the oil, so it's better than average on a per-mile basis. The viscosity did thicken up some compared to your virgin sample, but that didn't hurt anything that we can see. The trace of fuel is also harmless. Silicon was high. It looks harmless, but it never hurts to inspect air filtration to rule out dirt as a possibility. Good report.

@jimn.9990

10 ай бұрын

Paul, the oil filter that fits your vehicle is small and is not designed to reach 20k or 25k miles. The Amsoil Oil Filter (EA15k02) that fits your vehicle (which also works in my Toyota Camry Hybrid) is only designed to hold contaminates for 15k miles. Amsoil says if you use another filter, you shouldn’t go over 12k miles with that filter. In the event that you didn’t change your oil filter before reacting the 20,078 mile mark (when you had the oil tested), possibly that was the cause of the high level of silicon, which Blackstone didn't feel was harmful? Otherwise, like the comments on Blackstone’s report, impressive results! By the way, that is a very good testament in apparently using 0W-20 motor oil in the heat of Florida. Do you mostly drive on the highway or city driving or a combination? Thanks!

Oil analysis was available in the late 1980's. I had a 1986.5 Toyota Supra and had it done a couple of times.

Hey Jason! Can you recommend the third-party oil test lab? Or provide steps on how to get the Mobil1 sampling kit? Would love to do that on my car, just about to cross 200k miles.

How did you collect the oil? Should it be on the bottom where all the contaminates are located?

Cool bear and sample kit!

My Audi dealership, which has perhaps the best customer service on the planet, does oil analysis every time you get your fluids changed. Hilariously (and mostly due to Covid) I purchased a new Q5 SUV in July 2019, and I was alerted to a service (for the first time in my life) based in TIME. As in, instead of the dashboard saying “100 miles to next service” when you startup, it said “12 DAYS to next service.” Due to the lockdown and my extreme extra caution because I’m immunocompromised, after one year I had driven a grand total of 2,236 miles. Oil and other fluids really should be changed after a year no matter what, and luckily my results came back no concerns. I just thought it was cool that this dealership goes to these lengths to show how your engine is holding up. Hopefully in the next year I will have the opportunity to drive more. I like driving. And my sweet Irish Wolfhound LOVES going on drives, rides, trips, around the block, whatever. We need to do more of that.

@rogergeyer9851

2 жыл бұрын

Stephen Miles: Having sensors might be better. My friend, who drives a 25_ year old Mercedes changes the oil promptly when the car tells him to, roughly every 10K miles. It does it based on sensors detecting how much dirt the oil has in it. Many auto dealers, OTOH, want to charge you for service every chance they get, and also sell you things you don't need, so there's that.

@leumas75

2 жыл бұрын

@@rogergeyer9851 I agree with all of that. However, fluids really should be changed at least once a year, especially if one lives in a hot climate like I do. And all of my services up to 120,000 miles were included with the price of the car, which, because of my wife’s job, was a non-negotiable fixed price.