Please help the unhelpable

I have a 1996 camaro Z28 with what i think is a overheating problem. Temp range is 160(cold)-260(Red-veryhot) the middle is 210 and i would say at a idle my car can get up to 240ish. Can anyone help me? This is what exactly happens, when my car hits about 240ish i believe the fan kicks on and the temp comes down to around 210-220 but then goes right back up to the 240ish area. On really hot days i would say it never goes below 225. Any ideas?




Things i have done already:
Replaced Radiator
Put a 195 Termostat in
Flushed system
Replaced anti-freeze

Put a 195 Termostat in

Ahh, what about a matching cap? Either way, rule of thumb, when replacing the stat, replace the cap, a faulty cap causes the system to not pressurize, and the pressurization is what raises the boiling point.

Also make sure there is no air stuck in the system, jack the front end up so that the radiator neck is the highest point in the system, fire it up with the cap off, and I'll lay a couple of bucks on the table there will be asome air pockets coming out.

The cap isnt but a couple of months old and i doubt there is any air pockets in it because i had a chevy mechanic replace the coolant about 1 month ago.

The really only things im not realy sure about is that i know there are 2 electric fans on the radiator and not sure if both are running. Is one used for low temp and the other for high temp? also the heater core...not sure if thats a issue also.



EDIT: dont you mean bring the rear end up? consider ing my radiator sits at a angle faceing towards the interior.

Doesn't matter who serviced it, it is a very comon issue after the system has been opened.

On the fans, one is for when the a/c is on, (right side normally) and the other is for engine cooling. Should come on around 230 and off at 205-210. one option also is the OCM could be reprogrammed to ground the fan at a lower temp aswell.

On the edit? you jsut want the openin as the highest point in the system which normally requires lifting the front end.

Ok ill give that a try. But if i dont see any air pockets what else do you think i should look at? Also is it normal for 1996 camaro z28 LT1 5.7L V8 to run at around 240ish?

It's not far out of the range at all. As stated the, fan doesn't come on until after 230.

Well i guess the reason why im scared about it is cause if 160 is the lowest and 260 is the highest it looks like the redline starts at 250 and theres a white line right before that which im guessing is either 240 or 250... I have never seen a car go above the middle line. Which in my case is 210. Just yesterday my Overflow tank overflowed which means its getting really hot but i didnt notice any boiling. I dont know what else to say. I love my car and have already put so much money into it to just keep it in great shape. Im just scared that if the engine over heats and frys a piston or something then ill have to give my car up because the repair bill will be to far out of my range :(

Ok i just went out side to mess with my car and there were no air pockets in the system, So i called NAPA up and the guy told me a few things that im actually suppose to have a 180 stat in there but its not bad that i have a 195 because my system still is above the middle 210 mark and he also told me about a flap right under the bumper that directs air up to the radiator , when i went to check that flap it was actually down preventy air from going to my radiator so i ziped tied it up and will later check to see if my engine stays a decent temp. Also he told me that the cap and stat are good maintenance tools so i will go buy some new ones and put them in. If after all that and it still gets hot he told me that the fan may be working but maybe not spinning as fast as it should be spining and would need to be checked out.


If any of you can think of any other ideas what could be wrong and you please let me know so that i may check it.

Wait.. this 'flap' you zip tied it so it doesnt hang down anymore or what? Im confused on that part

The 'flap' which is called an air dam is there to put air up to your engine and cool it off.. so let it hang down, also if is broken or something, that too would cause your engine to overheat a bit.

Yes this piece was not suppose to be hanging down there are 3 holes in it where screws look like they use to go and attach to my frame right before the radiator. When i zip tied them up i can so where my air is suppose to goto to my radiator.

http://img184.imageshack.us/my.php?image=1996chevroletcamaroexpasssideaq6.jpgH ere is a better "visual" so you can see what im talking about


Other differance is my car is red :)


http://img184.imageshack.us/my.php?image=1996chevroletcamaroexpasssideaq6.jpg

Oh I get it.. thats weird, but have you checked yet if that was what caused it to keep overheating?

Not yet but in about a hour i will

yeah I believe that's just a debris guard to stop gunk (leaves) and whatnot from getting clogged inbetween the radiator and condensor like the 3rd gens.

ok i just tested it and its great my temp never go above 210 untill i was at very low speed like 10mph or was at a stop. Now i wonder why is it still able to get that high at an idle. Im thinking that one of the previous owners of that vehicle or maybe a car dealer changed when the fan should turn on/off

If you have the spare funding and or time, it would be worth your time to pick up a manual and do most of the repairs yourself. A lot of mechanics know what they're doing and you don't. So they overcharge or do things in a half-butt manner. I would call it jimmy wrigging.
I picked up a book after my first in shop experience. I noticed i got a whole lot more for a whole lot less. Not to mention if you're just a little mechanically inclined. The job will be quite easy.

Now by no means am I a smart mechanic. Although I have changed a couple transmissions and a drive shaft. A several other things as well. With no experience.

Personal Experience , shops = horrible. No reason you should have to get rid of your car if it overheats. Just buy a new engine or whatever you need. But anywho i'm not helping much so i'll get out of the post :)

meh, that sounds almost right, gotta remember there's not a whole lot of airflow under these hoods. Your Napa guy and I are on the same page, put a 180 stat in it and replace thae cap (hack, hang on to the one you just bought as a backup.

Now, since that cover was hanging, I would loosen up the radiator mounts and make sure no gook got built up inbetween the radiator and a/c condensor.

Asde from that, not much sounds horribly wrong. Now if it boils the overflow significantly, given it's age, I would start thinking about a new fan and keep on a eye on the water pump, but I hgighly don't concider either a problem.

Yeah it sounds like your problem is fixed.. my Monte goes abit over the middle line when im just sitting there at a stop.. so nothing to be alarmed about.

have you replaced the fan relays?? mine was getting hot and changed them and it fixed it

No i have not but i can also give that a try. So far when i zip tied that flap back up the temp doesnt seem to go above my thermostat which is either a 180 or 195...not sure. But when i come to a stop or i am going slow(anything under 20mph) my temp increases like it normally does. Well my thought on that though is my computer may be programed not to turn the fan on untill 240 or 245 and turn off at 210. So what i may try and do it find a shop that can "reprogram" it for me to turn on at 220 and off at 200. (Getting a shop to do it is much cheaper then going out and buying the reprogramer for $300...)


Other then that 2 things i could still look at are like you said the relay for the fans and may be the fan it self...ie if the fans are suppose to run at 2800 rpm and mine are at idk...2300 or somthing then i would need to look into getting a new fan motor.

well, if you're still concerned and think the fans are coming on late, instead of messing with the PCM I would mess with what feeds it it's info, the coolant temp sensor.

However, I really don't see you having much a problem to warrant it at this time.

I guess im just being "nit picky" I am the second owner of my car, the first owner never had any problems. When i got it about 1 year later i had to spend around $1300 in parts/labor to fix it and now i am working on the minor stuff to get it back in top shape. Like i need the cooling thing working(to my standards) a "low coolant sensor" rag top die, repainting, new E-brake line, new wipers...lol, and new i guess the "weather striping?" not sure about that one though...i know my car leaks from the windows so im guessing its the weather striping...not sure cause its a convertable...Currently the car just hit 138000 miles and engine/transmission are still in top shape(piston rings, flywheel, gears, pistons, compression are all still in great condition)

a "low coolant sensor"

:eek7: come again?

Nvm about the low coolant sensor, I just called the chevy dealer and they couldnt help me for anything...so i called another local repair shop and this is what they told me:

The temp sensor constantly sends a signal to the PCM saying what tempature its at at which point that it hits 225-228 the PCm sends a signal to energize the Relay to activate the "low speed" fan. If the temp continues to rise and hits 235+ the PCM sends another signal to the Relay to activate the "High speed fan". The mechanic told me that there is probably 2 things that could be wrong at this point. 1: Your temp sensor is sending incorrect information to your PCM 2: The low speed part of the relay is not kicking in/defective. So those are 2 things i need to check out now. At most this is going to cost me $80 (thats if i take it in and have a tech do it...) Im going to go buy a new relay today and go from there. I really apreciate all of you guys/gals help and i know i most likly wont talk to you ever again but in the case that i do ty again for everything and good luck with your future problems.

I have worked on many of these cars and own one myself and they all behave similar to what you describe. They ran hot from day one in most peoples opinions in regards to the way most of us were brought up to think "cooler is better".GM made these cars run like that for their own reasons. Primarily for emission purposes and to achive a more complete burn of the fuel to make uncle sam happy. My experience has been with my car before I made changes, that even on the hottest days I can idle my car in the driveway all day and the temp won't get hot at all but as soon as I start to drive it the temp climbs up into the ranges you describe. The design of the car isn't condusive to great cooling to start out with. One problem is there is little to no frontal area for air to flow through the radiator to aid in cooling and really no where for the air to go after gets under the hood anyway. That together makes the air dam that your talking about vital to the car not over heating. Are you still using the factory temp gauge on the dash board or are you using a aftermarket gauge? My real tempeture concerns started after I changed to a autometer gauge which is clearly more accurate and has a more defined scale on it. I think the factory gauge leaves a lot to be desired. Now everybody knows that a motor that runs cooler will make more power and that why you hear of everybody changing to lower temp thermostats and I do suggest you do that. I was able to get my temps down to a more acceptable level by making a few changes. First I changed to a Be Cool Radiator and that made a noticable temp drop. They are expensive but worth every penny. The stock radiators are aluminum also but don't work like the Be Cool units. Plus I'm not a big fan of the radiators with plastic side tanks that are prone to leaks. Secondly I changed the dual factory fans over to an aftermarket set that is triggered by a temp sender in the head and does not rely on the computer to turn on the fans like the factory set up Its common knowledge that the computer has the fans coming on way late in most peoples opinions. As the other guy said earlier you can change the temp they come on by changing the prom chip to a hypertech one or have one burned if you don't wanna change fans. Third I gave the air a place to go by installing a cowl hood. Also add a bottle of Redline Water Wetter to the cooling system. Its a good product and it works. Another thought is that if you are indeed using a aftermarket gauge or even the factory one the sender is typically located in the cyl head which normally will be the hottest spot on the motor and may not be a good indication of the overall temp of the motor when in contrast the water in the radiator could be signficantly cooler compared to the cyl. head. I don't ever fully trust the temp gauges and always confirm the temp by using one of those IR temp guns and check the temp at the thermostat housing to be sure. With the factory fan set up, the driver side fan is used as the primary cooling and the fan on the right side fan is considered the"super cooling" fan and will come on whenever the A/C is turned on or when the temp reaches a certain temp around 225 I believe. Even before I made my changes and used to worry that the car ran too hot, the secondary fan rarely came on which is sort of an indication that the temp is still in the acceptable range at least as far as the factory is concerned. One point of interest is that only the high performance Camaros ie: IROC and Z28 cars had the dual fans which was considered the heavy duty cooling system on these cars and otherwise all the other regular V8 cars relied on just a single fan for cooling. So again I would try to get the car to run a little cooler if only because heat is the biggest killer of engines and other components and will make more power and make the engine live longer, but be careful not to make radical changes to like a 160 stat without making the other changes that require a stat of that temp like a Hi Po computer chip for example because in stock form the computer needs the higher temps to run right and burn the fuel efficently and may cause issues running that cool on a stock chip. Good luck Long Live the FBody!