An old mechanic from Australia here! ..it is seriously hot here in summer and we used to have a lot of overheat problems in the 70's and 80's with even standard cars. Generally speaking, if you have an overheat problem at speed but it's okay at idle, then you have a water flow issue. If you have an overheat problem at idle but it's okay at speed then you have an airflow/heat exchange problem. Let me give you an example; early 70's 5 liter Fords sold here (with no A/C) had 2 core 6 cylinder radiators and 4 blade fans, never a problem even on a 45 degree day.. as long as you were moving!, stop in traffic though and the temp would go off the gauge. I had one of these cars and, like you, did the larger fan (which sounded like a jet engine), added a shroud, new water pump, different thermostats, multiple radiator and block flushes.. I could slow the overheating down but never completely get rid of it especially on a hot day. So I had a moan to the old radiator guy that I used and he came in the next day with a 4 core radiator from an A/C version of my car, told me to go back to the four blade fan and keep the shroud. Never had the problem again, the old boy said the original radiator (heat exchanger) simply did not have enough surface area for the job. It only worked adequately when air was forced through it (by driving). I remember him saying there needed to consistently be at least a 20 degree F difference in temperature between the inlet and outlet tank on the radiator with the car stationary at idle fully hot. Hope this helps..

A few years back I scored on a 89 Silverado k3500, 454, th400 and 4.10 gears. Months later summer rolling in and the engine is overheating. I began the process of changing out some components. Changed the thermostat and the antifreeze. Burped it a number of times. Changed the engine temperature sensor and burped a few more times. The thermostat and put a fan on the radiator. It had a new water pump and radiator when purchased it. I did a few more things so, not to waste more of your time, I went on line and replaced the spark plugs with OEM according to Chevy specs. Bingo ... no more overheating. Simple fix when the wrong plugs were put in.

@lightningfisher8177

Жыл бұрын

huh how bout that!

@TheKlamminator

10 ай бұрын

I'm hoping this is my issue with my 1990 suburban. Giving it a shot this week

I had a similar problem with my 65 289 V8 Falcon & Mustang. I did most of what you did except for adding two thermostatically controlled electric pusher fans in front of the condenser, and I got it to run at about 3/4 on the heat gauge. When overhaul time came, I got rid of the factory heads and installed World Windsor Junior heads and hooker headers to increase horsepower on the Falcon. Guess what? It runs much cooler with the high-performance heads.

I learned about this a little over 30 years ago when I was in my 20's. Not sure about Big Blocks, but small block chevys have a bunch upper and lower pulleys to choose from...for the long water pump. I always used the biggest lower pulley (7 to 8 inches in diameter), and the smallest upper pulley that would line up with it. The fan I always look for is a late 60s to early 70's 292 straight 6 truck fan. Its only a 4- blade, but the pitch isn't too bad, and it pulls a lot of air through the radiator (I try to put it between 1 to 2 inches from the radiator). Pulls enough air to hold a t-shirt against the radiator, at idle. One thing I read about in a Hot Rod magazine back in the 80's, was to add a couple lines to the back of the intake manifold, where the coolant dead-heads at the back end of the cylinder heads (on small and big blocks). Because the circulation is poor back there, the coolant heats up more in that area, and eventually that heat works its way forward. So when you tap into the intake manifold, join the two lines and send it to the waterneck (above the thermostat), you're not only creating a by-pass, but you're allowing the coolant to have another path to the radiator, without having to go through the hot coolant that's at the front of the engine. About 2 years ago, a guy in one of the facebook groups I was in, did this. He tried everything under the sun to cool his 454 down. And this by-pass was the solution.

This is helpful. Great analysis. Seems like everything is a tradeoff in some way. More to follow.

I didn't build my car, so I didn't realize it had an underdrive system. Came across the measurement of the stock pulley, which is 8". Took off the pretty aluminum pulleys, put stock sized (but not stock appearing) pulleys on, and it improved my alternator and cooling. Moved the (electric) fan against the radiator. Fixed a wiring error on the electric fan, so it runs all the time. Was in a parade this weekend, never got over 180 over the whole half hour and mile or two of steady idling.

@SS454LS6

Жыл бұрын

Real world results. Thanks for sharing!

Nice Chevelle buddy I own a 86 monte Carlo SS and has been swap for a 1968 350SBC

No vacuum advance at idle can cause overheating at idle! Check to see how much vacuum advance you are running and make sure you are attached to manifold vacant not ported vacuum!!!

That clutch is loud because you bought a HD clutch, it has nothing to do with the fan pitch. You don’t need the HD one. It’s probably too late to exchange it but you can sell it. I have a 4 core brass rad, 180* stat in my 19 70 Z28 with the stock 772 factory clutch fan and it rarely goes above 180*. BTW a clutch fan works better than an electric. Another thing, if you have a cooling overflow tank then the rad cap must be for a closed system.

I'd bite the bullet and go electric fans. I have the Frostbite electric fans and rad in my Chevelle. Nice and easy install, only had to buy an overflow tank for it.

This is why i like electric fans !

I swapped my v6 s10 from clutch n plastic fan to flex fan after autobone clutches would brake every year, really loud, but kept it cool

Great video. Try to swap out your steel fan for an S fan ...

19 inch 7 blade clutch fan from Summit Racing, Going with a bigger crank pully speed everything up "not good" . the difference in pulleys were huge, I would have went with a slightly smaller water pump pully.

You now have more fan and water pump rpm, more pitch, and a tight fan clutch, which are all positives..... The tradeoff is fan noise1! So ultimately, you need to decide if good cooling is worth the sounds..... I believe it is!

Reading the posts about the noise, and maybe the clutch not releasing. Could those bolts you used that werent the correct length maybe bottoming out and having an affect? Also could the noise be coming from the water pump bearings, you have addition weight on it with additional rpm. Just a gray hair guy thinking out loud.

once I think about it, what I think would work is the flex fan back on, no clutch, keep the overdriven pulley and a 160F thermostat

People always bandaid their cooling system with a flex fan and a lower thermostat/removal. If you have to do that you Have to rethink your understanding of how the cooling system works. Run a 195 degree thermostat, good fanclutch and good blade. 195 degrees isn't hot for most engines. They run more efficiently at that temp. Currently running a 6.2 diesel in my 70 C20 with a 190 degree thermostat with no issues. Also run a 195 thermostat on my 408 solid roller camaro and it never sees above 196 degrees in summer.

5.5 inch pulley diameter are for drag racing only . 6.25 crank pullies are ok Best to use with a high flow Edelbrock

On some of those Hayden clutches there is a way to adjust the temp that they release by moving the spring. If they don't have the adjustment on them you can modify them to change the release temp, which is a little lengthy to explain here. Something else that would help the clutch is to run the factory 7 blade fan designed for that application that pulls more air and helps the clutch act more like it should. They are pretty easy to find at swap meets. I run the complete factory setup on my 454 chevelle with factory AC, GM AC pulleys with the large crank and small water pump pulley setup that basically overdrives everything. Heavy duty Hayden clutch with the factory 7 blade fan. I can't get the car over 175 degrees at idle or cruise in 110 degree heat. The fan operates quietly. You can ride along here.. kzread.info/dash/bejne/l2hpl5uTgpisiKw.html With the factory overdriven pulley setup, I spin this thing to 6500 and in 35 years never lost the fan so no worries there..

@SS454LS6

3 жыл бұрын

Thanks for the post. Your car sounds great and I didn't hear any fan noise. I wonder if I can find a factory 7 blade fan that I can borrow to try out.

@kenf2662

3 жыл бұрын

@@SS454LS6 19 inch 7 blade clutch fan from Summit Racing

Here's an old circle track racing solution! When the water moves through the block TOO FAST it doesn't allow the heat from the block and heads to transfer into the water, resulting in an over heat problem. Solution: Cut off 4 of the 8 blades in the water pump to SLOW DOWN the waterflow through the engine. More heat energy is transferred into the water to be taken out to the radiator to be released into the atmosphere. This seems counter-intuitive but it WORKS!

I wonder if you should go with the steel fan and not aluminum. Have you considered going with the heavy duty clutch fan? Lastly the profile of the blades will cut down on sound. Rectangular vs. curved and yes you need a pitch. This video has been helpful as I’m dealing with heating issues on my big block. Are you bored over?

@SS454LS6

2 жыл бұрын

The Derale fan is steel. The noise might be because of my shroud. That's my best guess. Yes I am bored, 0.030 over. Id like to go electric fans but you need to spend the money for good parts to make sure it works right.

Maybe try the old fan with less pitch? Should be quieter but keep the larger crank pully. 🤷‍♂️

I think you need a water pump with an O.E.M. style cast impellor. I used to drive a big block Chevelle back in the day. I never had a problem with overheat until my factory water pump went bad and I replaced it with a rebuilt pump. From then on, nothing helped the overheating. I was too dense to make the association at the time. Those straight-blade, stamped impellors don't move nearly as much coolant.

@SS454LS6

11 ай бұрын

that very much could be the case. If i had $500 to throw around, I would love to try a different water pump.

What size of power steering pump pulley you have ? I got a sbc and I noticed my crankshaft pulley is a size 5.25 inches , ima switch to a 7 in pulley hope this works for my sbc

Yeah that fan is loud!

Try using your old fan. See if that works to still keep your engine running cooler and loose the bus noise

just go electric with a thermo sensor ... free horsepower too

Get some exhaust cutouts...you won’t hear that fan anymore 👍🏻😎

Same set up I am running now! Did you get a deal on that Hayden clutch? I just bought one(didn't need it but they were on sale for 31 dollars! USD) I do like how you showed each change you made. Surprised the fan didn't make that much of a difference but it does show it wasn't driven fast enough. Great video!

@SS454LS6

3 жыл бұрын

I think I paid regular price for the Hayden back in December. I thought the fan would make a noticeable difference as well.

@75zl1

3 жыл бұрын

@@SS454LS6oh I see. The Napa brand I am currently using isn't NEARLY as loud as yours. I'm honestly surprised. Only when the car is hot and it's 103f outside can I hear it... However I don't mind it since it let's me know it's working

@cuzz63

3 жыл бұрын

That surprised me also...clutch fans are pretty good at moving at air. It does seem the clutch fan is staying engaged, the noise is a known symptom of a failed thermo clutch....they sent you a bad one.

I have a 71 demon with a 318 with basically the same problem. During a restoration a performance cam and headers were added. A thirty minute ride yielded temps at idle similar to yours but AFTER I shut the engine down the temp gauge registered temperatures way past 240 (the gauge’s highest reading). Any ideas? Have you ever heard of temps rising so much with the engine off? I would blame the headers but I just don’t know. Great video. It has given me ideas and am thinking about what to do as a fix.

@cidertom5140

2 жыл бұрын

Is that a Detroit 318

@tobyparker95

2 жыл бұрын

Did u ever fix it?

@robertpaulis439

Жыл бұрын

Get OEM spark plugs. Gap to specs.

When running a fuel injection system on a Chevy 350 what seems to be the best thermostat at 185 165 how would you know what would be a good thermostat for it? Thanks

@SS454LS6

2 жыл бұрын

The Fitech will not run in closed loop until 170F, so I chose a 180 degree T-stat. That was the determining factor for me.

Them GM engineers were pretty smart. Chevy spent plenty of time snd money to create an efficient cooling system. One that would work in the winter of Alaska to the desert heat. Places like Death Valley, Baker hill and Vegas blvd in the heat of the day were real life test sites. Very rarely can a backyard engineer make much of an improvement over factory stock parts. Signed, one of them engineers who spent plenty of time validating component systems.

@rodneyhopper22

Жыл бұрын

Sorry so what s your point dude 🙄😎

@johnedwards6939

Жыл бұрын

@@rodneyhopper22 that if the factory system was intact with OEM parts. There wouldn’t be overheating issues.

Did you ever switch back to the other fan and test it again?

Was your Chevelle originally a small block car? If so your core support may be obstructing your radiator, which will cause the fan to work harder to pull air thru the radiator when I trimmed out the core support to the big block opening that quieted my fan quite a bit also after running about 200 miles the fan clutch loosened up a bit and my clutch fan made less noise than my flex fan. My chevelle is a 68 SS 468 cu in 4speed with a 3.08 posi. Maby this will help! I also hade to install an aluminum 3 core radiator that was capable of cooling 800 H. P.

@SS454LS6

2 жыл бұрын

my car is an original LS5 454 car.

@rodneyhopper22

Жыл бұрын

Just put a 4 blade fan on it and be done with the situation amen america job one and done and put a 3 or 4 core radiator in the car as well duh dude 🙄 what dumb asses really

@rodneyhopper22

Жыл бұрын

Maybe some common sense would help with your problem just saying 😉😂

i found the most common problem with big blocks overheating is the wrong head gasket. Series flow vs parallel flow. The parallel flow head gasket on a early block and head combination will always run hot and be prone to overheating.

@SS454LS6

2 жыл бұрын

Interesting, I haven't heard of the head gasket being a reason to cause overheating unless it was faulty. Something I will have to look into. Thanks

What did you do to fix the noise and keep the temp down?

@SS454LS6

2 жыл бұрын

Nothing to date. I have been looking for an original 7 blade fan locally to try, but no luck.

Put old fan back on and try that.but in my experience flex fans are really noisy too

Have you tried a combustion gas test kit for the radiator ? Maybe there is a crack on the engine

@SS454LS6

2 жыл бұрын

I haven't no. I think if there was a crack I would see water in the oil, or oil in the coolant, or excessive white smoke out the exhaust, or something. Not ruling it out though.

@Arizona_Vineyard

2 жыл бұрын

I thought i too had a crack or leaking head gasket. I used the block tester and it stayed blue. Arizona heat I can’t get my 454 dually down. Everything is stock. Im on my second engine and it still acts the same. Im about done with it. It’s stock so it shouldn’t need a bigger radiator. That’s not towing.

@rodneyhopper22

Жыл бұрын

Yeah just the one behind the wheel

Put the aluminum fan on the clutch it will be more quiet if it will fit the clutch

@SS454LS6

2 жыл бұрын

Standard fans and clutch fans are not interchangeable.

@johnmccabe4596

2 жыл бұрын

Stock ls6 wood be best g.m. did it for years .

Increase in torque to the fan

Arent those fans limited in rpm unlike a factory fan? I know they are heavier.

@SS454LS6

Жыл бұрын

I believe the Derale is quite a bit lighter than a 7 blade OEM steal fan. The Derale is also rated to 8000 rpm.

Not all hp is good hp. I have an underdrive pulley in my box. I went through like 5 alternators before I took the underdrive off.

@SS454LS6

2 жыл бұрын

absolutely

That fan clutch is faulty it should not be locked up while driving.Try to find a OE GM they work the best.

Seal off the gap between the front of the grille and The rad. You're recirculating hot air under your hood.

HI Aftermarket fans NEVER are as quiet as a factory unit . Genuine Blade design rules . Thermal hub might be faulty eg continual drive of fan Recommended to run 180F --82 deg cel thermostat , warm hot oil burns off waste fuel etc and oil will just flow better .

It might just be me,,, but it looks like the fan is pushing instead of pulling the air through the radiator

@SS454LS6

10 ай бұрын

It's definitely pulling. I've done the paper test among other tests.

I was thinking.... And saw your thread on the Chevelle forum that I'm not a member of... Were your crank and water pump pulley a 'matched' performance set? The water pump pulley could have been slightly larger to compensate for the smaller crank pulley. If that's the case it's being driven even faster now. I would measure both pulleys to find a ratio and compare that to original gm.

@SS454LS6

3 жыл бұрын

i believe stock is 1.125:1 overdriven. With a 7" crank and 6.25" water pump pulley, I am 1.12:1 overdriven.

@75zl1

3 жыл бұрын

@@SS454LS6 well I'm out of guesses... Could be a stick fan clutch. I never hear mine in the 68 now. Only when it's HOT

Lower pulley should be 7 1/4 inches!

Fan noise, like helicopter blade slicing thru air.

Sounds like you have a defective clutch. Just because it’s new, doesn’t mean it’s good. Exchange your fan clutch

@rodneyhopper22

Жыл бұрын

Hey use a lower temperature thermostat like a 160 degree Mr I'm so smart

@rodneyhopper22

Жыл бұрын

And get a regular 4 blade fan for it done with the situation

@mikeburnett7028

Жыл бұрын

@@rodneyhopper22 lowering thermostat not working. It just opens earlier

Your problem is your thermostat, must use OE , not using the right thermostat will create all kinds of problems.

@rodneyhopper22

Жыл бұрын

Try using a lower temperature thermostat like a 160 degree or 170 hello there 🙄 duh

@JuanCM1957

Жыл бұрын

@@rodneyhopper22 you apparently don’t understand how thermostats work, get educated first and then get back to me.

@oxyfee6486

Жыл бұрын

I have a 195 in my 67 Camaro, I have never had a problem with heat, even idling in traffic on a hot day.

The problem you are having is with the fan clutch it’s self when you order a fan clutch you also have to have your gear ratio information I would remove the fan clutch and go buy one that is for your car that one apparently is not it is probably for a big dump truck engine and not a car. You do not want electrical fans because they are Way more noisier than what you are experiencing with your fan and clutch believe me electric fans suck.

Your idle is way too fast - should be 400-500 nice low and Lopey

@SS454LS6

2 жыл бұрын

400-500 is way too low. Besides, I need some idle RPM to turn the fans and water pump. 800 rpm is normal.

@cidertom5140

2 жыл бұрын

@@SS454LS6 not for a big block. There’s one of a big block at 350-400.400 is better than nothing.

@jeremymcmulin6876

2 жыл бұрын

@@cidertom5140 I don’t think my 496 will run that low. Any size camshaft needs much more idle.