Thread: Delayed overheating problem

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Took it for a spin to test the new fan position, the temperature still climbed above 210 (before going back down) but this time it didn't reach the redline, it was probably halfway between ideal and redline, so I guess that's some progress. My next step will be replacing the thermostat with a sleeve style thermostat and seeing how that works. I'll update when I get that taken care of.

Thanks for all your advice guys, you've been extremely helpful through this.

Keep in mind you are seeing a delayed reaction on your gauge when the thermostat opens. The temperature it reads is the elevated temperature at the sending unit (exit point) just before the coolant from the radiator reaches it (reading the heated block coolant first). There will be a temperature rise from the coolant in the block before the coolant from the radiator reaches the sending unit after the thermostat opens.

A 190° thermostat could easily read 210° at the sending unit prior to the coolant from the radiator reaching it, then settling down to normal temps which could still be 10-30° higher at the exit point of the motor than at the radiators exit (entrance to motor).

High flow thermostat;
180°
http://www.summitracing.com/parts/mil-16401/overview/
http://www.summitracing.com/parts/mrg-4364/overview/

160°
http://www.summitracing.com/parts/mil-16400/overview/
http://www.summitracing.com/parts/mrg-4363/overview/

Sounds like you're gaining on it, Megaman. The better thermostat may help considerably also. These other members are much more knowledgeable than myself but I had just gone thru what you are dealing with and wanted to mention the things I had noticed to see if they might help. I would also like to mention here that you are a very polite, informative and appreciative poster. The special effort you take to thank and acknowledge each member that has offered a suggestion for you is very commendable.
Good Luck with your project,
meller

Mega, in the provided examples of thermostats, the 16400 and 16401 are the sleeve type, and it seems my memory of pricing is skewed!

And Meller is right, you should be commended for your approach to dealings in this forum. So thanks for that! Good Job!

A lesson this cranky old bloke should take on board at times too, be polite and mindful of others. Back to the subject on hand, you mentioned checking the bottom radiator hose and decided it appeared soft, I would recommend you replace it and make sure it has the coiled spring inside. When I read your original post I thought of the hose sucking in itself straight away but the other guys have all feed you good information to try. Your Camaro is my all time favourite model above the sixties models even but then, some people say I'm sick in the head.....

It's actually a cheat, but you could add an oil cooler.

Summit has some nice diverter kits which mount under the oil filter, and have a thermal bypass to bypass in cold weather.

Originally Posted by 36 sedan

Keep in mind you are seeing a delayed reaction on your gauge when the thermostat opens. The temperature it reads is the elevated temperature at the sending unit (exit point) just before the coolant from the radiator reaches it (reading the heated block coolant first). There will be a temperature rise from the coolant in the block before the coolant from the radiator reaches the sending unit after the thermostat opens.

A 190° thermostat could easily read 210° at the sending unit prior to the coolant from the radiator reaching it, then settling down to normal temps which could still be 10-30° higher at the exit point of the motor than at the radiators exit (entrance to motor).

High flow thermostat;
180°
http://www.summitracing.com/parts/mil-16401/overview/
http://www.summitracing.com/parts/mrg-4364/overview/

160°
http://www.summitracing.com/parts/mil-16400/overview/
http://www.summitracing.com/parts/mrg-4363/overview/

Originally Posted by MelloYello

Sounds like you're gaining on it, Megaman. The better thermostat may help considerably also. These other members are much more knowledgeable than myself but I had just gone thru what you are dealing with and wanted to mention the things I had noticed to see if they might help. I would also like to mention here that you are a very polite, informative and appreciative poster. The special effort you take to thank and acknowledge each member that has offered a suggestion for you is very commendable.
Good Luck with your project,
meller

Originally Posted by 34_40

Mega, in the provided examples of thermostats, the 16400 and 16401 are the sleeve type, and it seems my memory of pricing is skewed!

And Meller is right, you should be commended for your approach to dealings in this forum. So thanks for that! Good Job!

Originally Posted by Whiplash23T

A lesson this cranky old bloke should take on board at times too, be polite and mindful of others. Back to the subject on hand, you mentioned checking the bottom radiator hose and decided it appeared soft, I would recommend you replace it and make sure it has the coiled spring inside. When I read your original post I thought of the hose sucking in itself straight away but the other guys have all feed you good information to try. Your Camaro is my all time favourite model above the sixties models even but then, some people say I'm sick in the head.....

Originally Posted by firebird77clone

It's actually a cheat, but you could add an oil cooler.

Summit has some nice diverter kits which mount under the oil filter, and have a thermal bypass to bypass in cold weather.

I really appreciate the kind words, I can't believe the posters online that are rude to the people that are trying to help them. But you guys truly deserve the appreciation, you're offering me advice that you could basically charge to do. It's extremely helpful, I thought I understood the drive train after rebuilding everything with my dad, but there is so many nuances that I think it's practically an art and I'm very grateful for all the help you've given me.

Update: I bought a new thermostat today, the sleeve style that the company, Mr. Gasket, makes and installed it along with a new gasket (only after entirely removing the old gasket). I then fired it up and took it for a test ride. Ironically, now it's a little too cold, haha. It stays at around 140-150 F, even after applying the old lead foot. Perhaps the old thermostat was just sticking? But I'm not sure, perhaps there's more to this than I originally thought. Or maybe I should just throw on some performance upgrades that will make it run hotter to make up for it. Just kidding (sorta, haha).

Originally Posted by megamax42

Update: I bought a new thermostat today, the sleeve style that the company, Mr. Gasket, makes and installed it along with a new gasket (only after entirely removing the old gasket). I then fired it up and took it for a test ride. Ironically, now it's a little too cold, haha. It stays at around 140-150 F, even after applying the old lead foot. Perhaps the old thermostat was just sticking? But I'm not sure, perhaps there's more to this than I originally thought. Or maybe I should just throw on some performance upgrades that will make it run hotter to make up for it. Just kidding (sorta, haha).

What was the heat rating of the T-Stat that you purchased?

You might consider getting a hotter tstat of the same mfg/type.

I've seen posted here that below 180 will cause sludge build up.

This just in- are you certain you didn't have the old tstat installed backwards?

Megamax, I hate to jump in before you've had an opportunity to reply, and I also hate that I didn't offer this to you earlier, before you installed the new T-stat but I always drill a small, nominal 1/8" hole in the flat flange of the T-stat to promote faster warmup, but more important to make filling the system soooooo much easier by giving the trapped air a way to bleed out of the block. It eliminates the old "burping" of the system, waiting for the stat to open to add that last 1/2 gallon of coolant and often losing half of it on the ground as the system burps. The hole doesn't affect operation, so you might consider drilling a little hole if you need to swap out that stat for a warmer one. I wouldn't go any cooler than 180F, and 190-195F is about the lowest any OEM goes in the past ten years or more for better efficiency on the burn. Consider where your temp sensor is located in choosing your stat, too.

Originally Posted by 34_40

What was the heat rating of the T-Stat that you purchased?

Originally Posted by firebird77clone

You might consider getting a hotter tstat of the same mfg/type.

I've seen posted here that below 180 will cause sludge build up.

Originally Posted by firebird77clone

This just in- are you certain you didn't have the old tstat installed backwards?

Originally Posted by rspears

Megamax, I hate to jump in before you've had an opportunity to reply, and I also hate that I didn't offer this to you earlier, before you installed the new T-stat but I always drill a small, nominal 1/8" hole in the flat flange of the T-stat to promote faster warmup, but more important to make filling the system soooooo much easier by giving the trapped air a way to bleed out of the block. It eliminates the old "burping" of the system, waiting for the stat to open to add that last 1/2 gallon of coolant and often losing half of it on the ground as the system burps. The hole doesn't affect operation, so you might consider drilling a little hole if you need to swap out that stat for a warmer one. I wouldn't go any cooler than 180F, and 190-195F is about the lowest any OEM goes in the past ten years or more for better efficiency on the burn. Consider where your temp sensor is located in choosing your stat, too.

I appreciate the replies everyone, sounds like this should hopefully be easier than I initially thought.


34_40:
The sleeve style thermostat I bought was rated at 180 F I believe, I'll go check the package to confirm.

firebird77clone:
If I remember correctly O'Reillys didn't have any hotter than 180, but I'm sure there's some online, I'll go check it out. I'm pretty sure I had the old one installed correctly, although that would be pretty hilarious if it was backwards. I had it installed the same direction as this photo:



rspears:
Oh no worries, it's all been a cool learning experience. I believe the old thermostat I took out was rated at 180 also, would I be ok drilling the hole and re-installing the old one? Sounds like a cool idea, quick question, is there any way to drain the upper radiator hose so I don't get coolant everywhere when I take the water neck off?

Originally Posted by megamax42

I believe the old thermostat I took out was rated at 180 also, would I be ok drilling the hole and re-installing the old one? Sounds like a cool idea, quick question, is there any way to drain the upper radiator hose so I don't get coolant everywhere when I take the water neck off?

The old one seemed to be sticking, so why would you consider re-installing it? Throw it away!! If you get the engine warm before you open the drain cock on the radiator the coolant will drop below the water neck and you shouldn't lose much at all. If you drain it cold the t-stat will be closed, and the upper hose will tend to hold coolant. With the hole it doesn't matter, it'll drain back either way, but slowly.

I wouldn't do a thing!! Until I verified with some separate tool what the temperature really was! I think you gauge is "off"..

Beg, borrow, buy a temperature gun that uses a laser, that's the easiest that I know of - for taking temps while the engine is operating.

Bring it up to full temp and then measure at the t-stat housing, the hose, the top tank of the radiator and then the bottom.. compare with your dash gauge.

Great thread and let me also add my welcome to you megamax. I would second those who have appreciated your polite and positive attitude. It goes a long way here as many of us are old guys and well – we just prefer polite rather than rude behavior!

A couple thoughts from an ol’ Chevy guy who’s built a lot of small blocks and worked through any number of heat related issues:

1. They guys here recommending mechanical fans are spot on. The GM boys have done a lot of research and there’s no better cooling method than the stock GM fan and the stock clutch. If you can go to a wrecking yard and find the fan, clutch and shroud from a pre-1982 Camaro V8 you’ll do well to replace everything. Even a 40 year old clutch is probably fine; however the fan clutches from NAPA are functional replacements, usually made by Hayden (the originals were made by Eaton and Schwitzer). If there are any signs of leakage or the bearing wobbles replace the clutch – about $50 from a parts house. But the one for A/C as its heavy duty.

2. Get your timing set – Summit, Jegs and your local parts house have the timing tabs for less than five bucks. Start with initial timing 8-10 degrees advanced, vacuum disconnected, total timing should be 33-36 degrees with the vacuum connected @ 2000-2500 RPM.

3. Your negative battery cable looks kinda funky. Remember this is the electrical path for everything on your car and the starter draws 100-125 amps on a stock engine. Remove the cable and clean the ends really well on your wire wheel or with sand paper. Also grind the bracket to bare metal and attach with a 5/16” bolt and nut with star washers. Use a nice new Grade 5 and reef on it good and tight. Make sure the positive cable is real clean as well!

Keep up the great posts and once again, welcome to CHR

Best,Glenn