I have a 1992 RS with a stock 305 V8. I have flushed then re-cored the radiator, replaced the thermostat, replaced the lower radiator hose, replaced the heater core, replaced all heater hoses, checked the fan, and replaced the water pump. It still runs hot. Any ideas what to check next?

Have your timing checked. KZ

<BLOCKQUOTE>quote:</font><HR>Originally posted by lori:
I have a 1992 RS with a stock 305 V8. I have flushed then re-cored the radiator, replaced the thermostat, replaced the lower radiator hose, replaced the heater core, replaced all heater hoses, checked the fan, and replaced the water pump. It still runs hot. Any ideas what to check next?<HR></BLOCKQUOTE>

<BLOCKQUOTE>quote:</font><HR>Originally posted by Dee:
<HR></BLOCKQUOTE>

Have a manual fan installed as in mine the fan is working but doesn"t run enough to keep the engine cool.This way you can turn it on when you see the temperature gauge climbing!
Apparently nothing wrong in my car either but it still overheats especially when idling for a very short time.So after checking all the same parts you did and changing them all this worked! Goood Luck

Here's the thing! It overheats only when the car is moving! If it sits idle, it won't overheat. It hardly even runs hot when it's idle - maybe ten to fifteen degrees more than normal.

Hi Lori.
Here is my dumb question for the day. Have you taken it to the dealer to compare actual temperature to what the guage is reading. I have had several in the past (92s) that were reading incorrectly by 10-15 degrees.

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67 SS
70 Z/28

No, I haven't taken it to the dealer to verify the actual temperature. But, that's because if the water in the reserve tank is boiling, it has to be too hot! It only overheats when I drive over 45 mph when the outside temperature is 85+ degrees. It never overheats when it is idle.

It just dawned on me. Is your air dam missing underneath? This will be the problem if it is missing. Usually everyone scrapes this off on a curb, I have done that before.
It diverts the air up into the radiator. When your traveling at speed, no air will get in.

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67 SS
70 Z/28

Guy you have a good point there but, I'm a gonna ask another dumb question. Did ya change the radiator cap when you changed everything else ?

71 Camairo


[This message has been edited by 71 Camairo (edited 04-19-2000).]

I thought of the air dam, too. I had taken mine off due to some damage. I replaced it soon after I started having these overheating problems. Even after replacing the air dam, it is still running hot. And, yes, I did replace the radiator cap when I had the radiator re-cored. What are the chances that a water jacket is clogged? This is certainly not my area of expertise! So, I don't even know if that is a logical question. And, to add further to the discussion, running the AC makes it overheat much faster. Running with the heater as high as it will go helps to a certain degree. But, that is not a viable solution for the hot, humid summers here in the south!

The only other suggestion is to do what KZ suggested and have your timing checked.


71 Camairo

Is that an electric fan or does it have a fan clutch? The clutches go bad.

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67 410sb 11.63 @117.6

Yes Lonnie...but if it were the fan clutch...it would REALLY overheat at idle.

I would agree that you should have the timing checked. Does the motor "knock" or "ping"?


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Steve McCorry - Central Ohio Camaro Club
'69 Camaro RS/SS-350 - Daytona Yellow
'95 Camaro Z-28 - Sebring Silver
click here to see my car ---&gt; www.mindspring.com/~mccorry (http://www.mindspring.com/~mccorry)

Is the fan running the right way, pulling the air thru the radiator? It's just a DC motor, if the wires got reversed....

Got the right water pump for your serpentine belt system" I think some of the systems run the water pump backwards and take a different impeller. I think it's just the vette system.

The fan is electric. It checked out OK. It's pulling air in the right direction. I have considered adding a toggle switch to it just so that I can turn it on at all times if I so choose. But, the only benefit I see in that is that it would help to keep the car cool when it's idling. It doesn't make much sense to me to do that since the car doesn't actually overheat until the car is moving at a higher rate of speed in warmer weather. It runs a little warm when idling, but nowhere near the point of overheating.

The water pump is the right one. Actually, I think the one that I had on there to begin with was still good. I was just concerned that it might not be pumping enough water to the motor. So, I replaced it since it was a fairly simple task.

Oh! And, no, there is no knocking, pinging, or any other unusual noises anywhere at any time!

Is your car an auto or stick? A long shot but if the auto trans is getting hot it could be transfering the heat to the motor.

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...Dennis
Topless'69 (http://home1.gte.net/ddunio/topless69)
rsss.fun@gte.net

Here is another shot. I have had catalytic converters plugged before causing the engine to run a little warm. Maybe?

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67 SS
70 Z/28

Try removing the thermostat, and run without it - I have had new thermostats that would stick closed.

Running without a thermostat will only cause the coolant to circulate through the system continuously. This doesn't allow the heat to transfer from the metal to the liquid fully and makes for a less efficient system.

To check your thermostat put it in a pan of water on the stove (old can would be better) and heat it up. You will hear it pop when it opens. You can put a thermometer in to verify the temp it opens at...


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...Dennis
Topless'69 (http://home1.gte.net/ddunio/topless69)
rsss.fun@gte.net

It's an automatic transmission. And, the first thing I checked was the thermostat! It's fine. I didn't think about the catalytic converter. I will look into that.

Try a 30 percent anti-freeze/60 percent tap water coolant mix, not the 50/50. Water cools better than anti/freeze, and high anti-freeze content will cause overheating. Please, never run without a thremostat.

I tried running the less antifreeze/more water trick. That didn't work, either. It helped some, but not nearly enough to keep the car from overheating. And, I have bettter sense than to run without a thermostat under the circumstances. Without the thermostat, the water constantly circulates. Thus, it doesn't have an opportunity to cool at all. It actually overheated more quickly when I removed the thermostat and drove for about ten miles.

Has it stored any trouble codes?? Lots of things can cause this over and above the cooling system. Leanness from dirty injectors won't nescessarily cause detonate or reduce power significantly. Codes may help point to a cause.

Here's another very, very long shot, and I doubt this is it, but...some small block water pumps rotate backwards, but you'd see massive overheating fairly soon after startup with one. Like I said, very slim chance.

lori - From the looks of it you have covered the basic's of the cooling system without resolving your problem. With the cooling system working correctly you need to figure out what is making more heat than normal! Timing will also effect this but the norm is hot at idle, cools down when driving as the advance increases. If your not getting any advance I think you would notice poor preformance...

You said <BLOCKQUOTE>quote:</font><HR>Here's the thing! It overheats only when the car is moving! If it sits idle, it won't overheat. It hardly even runs hot when it's idle - maybe ten to fifteen degrees more than normal.<HR></BLOCKQUOTE>

Something is creating more heat than it should or it would not go up 10-15deg when idleing and even higher when going down the road!

Have your oil analized for metal particles (jiffy lube and the like can send out a sample for you). Something inside may be going away! http://www.camaros.net/forum/eek.gif Have your trans and torque converter checked if they are getting hotter than they should the heat will transfer to the motor... Same with your catalytic converter if plugged it will generate heat!

Some of this has been suggested already but is well worth repeating... Let us know what you find.


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...Dennis
Topless'69 (http://home1.gte.net/ddunio/topless69)
rsss.fun@gte.net

I had to engine oil analyzed. The report came back with a statement along the lines of we can't believe that this motor has nearly 160,000 miles on it! Evidently, there was no evidence of any problems within the engine itself. If the transmission (or anything else for that matter) is giving off that much heat, wouldn't I notice some poor performance other than in overheating problems? And, wouldn't it be obvious performance-wise if the catalytic converter was clogged?

By the way, I appreciate all of the responses!

Have you had your radiator cap checked? A leaky cap will allow the engine to run hotter due to pressure loss.

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68 RS Ash Gold

How long have you had the car? Maybe the performance decrease has just evolved a little at a time? You might not have noticed. I had a dist with a bent shaft and my car ran great until I fixed the bent shaft... Then I found out how much better it ran. Something has to be heating up, and there is not much else left! Don't give up...


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...Dennis
Topless'69 (http://home1.gte.net/ddunio/topless69)
rsss.fun@gte.net

I replaced the radiator cap when the radiator was recored. I have checked the cap to make sure it's OK.

I know that something is heating up somewhere! The question is simply what! The only real performance problems I have noticed is the need for new plugs and new shocks. Other than that, it runs like a champ! I bought the car from its original owner when it was less than a year old (about 8500 miles). I have been the sole driver of the car (with a few, rare exceptions). And, it now has over 165,000 original miles. So, even though performance could degrade over time, I don't think that it has done so without my noticing.

I won't give up on this car! I loved it the first time I saw it. And, took it home without question before the dealer even had a chance to put it on the lot! I am just about to the point of rebuilding the motor if I can't get this cleared up, though. And, I would like to avoid that until next spring if at all possible! I am just running out of ideas.

Hmmm. With everything that has been verified, could you have a partially plugged coolant passage in the block/head? Did this overheating problem suddenly appear? With your mileage, sediment could have gradually built up.

The problem did appear rather suddenly. I was making a 100-mile drive, with the AC on high, driving about 85 mph, in 105-degree heat. The car overheated as soon as I arrived at my destination. My first inclination was the thermostat. And, sure enough, it was literally in two separate pieces. So, I replaced it. It was still overheating. So, I flushed the radiator, replaced the relay switch to the fan (it's given me quite a bit of trouble in the past), replaced the radiator hoses, and finally recored the radiator. I tried different antifreeze/water mixtures. I ended up replacing the water pump shortly thereafter. After the heater core dumped antifreeze into my floor board, I replaced it and all of the hoses. This "little" problem is going to nickel and dime me to death! I thought about something being clogged somewhere within the engine itself. But, in order to tear into that, I might as well be prepared to rebuild the motor. I don't want to do that just yet unless I have to. If there is a clog somewhere within the motor, is it possible to detect without pulling it apart?