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Have a 71 elky w/402.. Runs fine, being told that that it is running too hot. about 198 when running, about 205 when stopped. With the air on and running about 210, stopped about 220/225. Any thoughts
 

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Does it run at those temps on a hot summer day? If so, they aren't too bad. Try a cooling system flush, that might clean some of the grime outta the radiator and help it cool a little better. also make sure that you have the 4-bolt radiator support, not the 3-bolt one. If you have the 3-bolt support, it indicates that you have a radiator designed for a small block, NON-AC car. All big blocks and/or AC cars should have the larger radiator that uses the support with 4 bolts accross the top. (the "support" I'm talking about is the piece of stamped steel that sits on top of your radiator. there should be a sticker on it where you find engine tuning and emissions info.)

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Ian McDermott
Columbia University
New York, NY.
1970 Chevelle SS 396
[email protected]
chevelle.dhs.org





[This message has been edited by Havoc (edited 03-23-99).]
 

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Hey there Ocala-71 Elky, I had the same problem with my SS454 P/U and had a 5 core radiator built for it, cured the problem completly, any radiator shop can order the core and use regular 4 core tanks cost total deal about, 300 bucks much cheaper than a custom catalog type cooler, Im just south of Sarasota welcome to www.chevelles.com L89SEDAN
 

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Has any one seen this stuff in a can that says it will drop your engine temp. by 40 degrees? It is a liquid you add to your coolant.I have seen it at swap meets and at local parts stores and wonder if it is any thing woth trying. My 396 runs hot in the summer and hotter after it is shut down.
 

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Can we assume you have checked your t'stat, and have a fan shroud in place that fits relatively close to the radiator and fan ??
Check the easy cheap stuff before going to expensive custom radiators - although, if all else is right, that may be necessary.

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I have a friend who has a 66 GTO with a BB Chevy engine in it. It also runs a little hot, probably around the same temp range you've listed (although he has no a/c to worry about). For about 10 years now he has tried everything under the sun to get it to run aound 180 degrees. I think he's finally given up, because there's nothing else (short of snake oil remedies) to be tried. I suspect that some blocks and/or heads have internal casting flaws causing some flow restrictions within the cooling system, that just can't be fixed without getting new or different bare blocks/heads.
 

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I had the same problem with my 70 BB. The factory uses a 195 F. T'stat. All of my investigations, talks with other BB guys/gals, said to switch to a 160-165 F. t'stat. Worked like a charm! Now, as soon as the temp gets to 180, the engine responds with all that its got! I do not vary much from that temp and I definitly stay below 200 F. If this does not work, then try it without a thermostat. If you run cool almost all the time, less than 180, then the system should be fine, i.e. clear of an blockage, and the thermostat will do its job. If you still run fine, then you need to flush the system and take it from there. ( Like the earlier note said about doing the easy stuff first.)

Small steps at a time equals less money spent needlessly. ( I have a lot of experience with that and I am still learning.)

Good luck!
 

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if your temp sender is located in the head, then you're doing alright. the head is 20 degrees hotter than the temp boss on your intake. double check your timming, too much advance makes you hot. switching the vacuum advance from a timmed port to full manifold vacuum also helps idle temp. my friend's 462 ran 210 for 5yrs, last month the 19.5" flex fan fragged. flex lite's replacement with the same part number now cools it to 180, all the time!
good luck, all the new cars with aluminum heads run at 210.
 

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Here's an idea:

Are you sure that your temp gauge is giving an accurate reading? I have a 70SS with gauge package. The stock temp gauge reads a constant 190 while I'm running a 180 thermostat. I think that it just reads slightly higher.

Does anyone have an idea as to how elky71 can get a more direct temp measurement (like a manual thermometer?)
 

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I know you can check a thermostat by putting it in water with a meat thermostat bring water temp up and watch when it opens, I suppose you could do the same thing with it in the radiator if your cap is off to check gauge accuracy, watch water level, I'd make sure level in raditor is about half full cold, water expands as it gets hot, don't want it running out the top.
 

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rickk, I dont think your 70 came with a 195 thermostat, probably a 180. If you run your engine without a thermostat the coolant wont circulate to the back of the engine and then you will have an overheating problem. Do the checks already listed and make sure your timing isnt retarded that will definitly make it run hot.
 

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Discussion Starter #12
The radiator is a four bolt system. Indicating the larger core. There is a larger plastic shroud that extends over the back of the radiator and sides, not broken at all,looks fairly new. There is a seven blade fan. All belts are tight and in good shape. I have a HEI installed, so I have replaced the gauges with Airgauges. Living in Central Florida means running in hot. The summer isn't here yet, so when should I shut it down. 230/240???, or is there something else I should do. Thanks for your replies, I knew I like chevelles.
 
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195 would've been the stock thermostat in 70. I wouldn't run without a thermostat, either.
 

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Chev64 and Larry,

Thanks Larry. I checked my books for the temp on the t'stat for this vehicle. It is 195 F. some of the older 350 cu. and earlier Chevelles used a 180 F T'stat.

Running without a thermostat is not what I was recommending. This proceedure was just a checking tool and driving the car for an hour without a T'stat is not going to do any harm.

Clarifying the T'stat function and the water flow. The T'stat is used to keep the engine at a specific range of operating temperatures. It is not a constant 195 f. Just as a 165f does not make the engine run at a constant 165f.

The t'stat allows the engine to warm up quicker for more efficient use of fuel.

The T'stat also allows the coolant to stay in the radiator so that the heat in the coolant can be transferred or expelled into the air and away from the engine. The t'stat does not make the coolant flow evenly throughout the engine. This is the job of the water pump.

The problem that you do run into when you run the engine for any great length of time without a t'stat IS an over heated engine. But this is because the coolant never gets a chance to stay in the radiator for any length of time. Coolant needs to come to a "rest" in the radiator in order for the radiator to "take" as much heat out of the coolant as possible. That is why a radiator is also called a "heat exchanger".

If the coolant is not allowed to become significantly different in temperature than the engine, then the coolant starts to become the same temperature as the engine and will begin to rise in temp along with the engine because the coolants "base line" temp is only as low as the engine's.

With a t'stat, the coolant is allowed to get lower than the engine's and only then can it "take" heat away from a hotter source, i.e. the engine.

I hope this helps out.
 

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Have you tried an external fan to help air flow? That has helped me with that problem. I was running a little hot and turned it on and watched the temp drop.
 
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