R Cook 92

Ok My car (92 auto) runs at about 220-235 on a regular basis. This seems hot is there a way to get that down?
Today I start my car, go inside and let it run for about 10 minutes to get my a/c nice and cool. Well, I come outside and my hood is smoking from all the seems!!! My interior is scorching hot(and you should have seen my eyes when I saw the outside temp reading 161!!!) I pop the hood and my overflow tank is spraying coolant out of the cap..and the surge tank cap is spraying too, but not as much... What could be wrong...????
So I drive it and it cools from....ready...280 degrees!!! down to normal temp... then I go through the drive through, and after about 1 minute, its up to 260!! Could this be thermostat???? I bought one cause I don't want to risk my water pump... but anyother suggestions???
Also, I've heard the dex cool isn't all its cracked up to be, GM is finding out it clumps up??? any experiences... I flushed my and filled with dex cool last year...is it really better????
Last one... Can I go from the stock thermostat(isn't it 180) down to 160 with out changing my chip, or fan switch...etc...???

It was about 93 degrees here today, with a heat index of 107, and I check the coolant regularly, and it WASN'T low...

Thanks, sorry for the length, I'll apprieciate ANY suggestions!!

Randy
hot 92 auto coupe.

GlockLT4

STOP DRIVING YOUR CAR AT 260-280 DEGREES!

You are doing much more harm than you think running at these temps. You will surely warp a head and other things around 280 degrees. PLUS... why are you risking your engine for a burrito????

1) Did you check to be sure you don't have a giant piece of plastic or something stuck in your radiator?

2) Did you blead the air out of your coolant system last time your flushed it?

3) Don't run your vette if you see temps near 260º or... god... 280º. Pull over and let it cool down for a few minutes. 260º is considered to be "overheated" on most GM vehicles.

4) Are you sure your water pump is working properly and circulating water? Sounds like something might be busted in that area.

5) Are your fans kicking in? At 228º the main fan should kick in to keep it cooler. When you turn on your A/C, the fan should turn on as well.

At 280º I am guessing that your seals are gone, your radiator hoses are busted, and more.

Do NOT put Dexcool (the orange/redish stuff) in your system. It will leak and do all kinds of stuff. Only '94-'95 have the option of using it. Only '96 was factory filled with it.

I suspect it is not your t-stat because if it was staying closed, then the hot water from the engine wouldn't get to your radiator or the overflow tank. If you say fluid came shooting out the overflow tank, then how'd it get there with a t-stat frozen (sorry.. bad choice of word.. ) shut.


My '94 comes with a 180º t-stat. I do not remember if the '92 comes with 195º or 180º.

vettenuts

Don't agree with this one. Dexcool is a superior coolant and is not the source of this problem. I would check the following]

1. Plugged radiator, the "green stuff" and the required sealer pellets may have caused the radiator to plug up internally.

2. Check the air passages and make sure you don't have any blockage.

3. Start car with cap off of the tank (where you fill it), you should see coolant flowing in from the pump into the tank as soon as the motor start. This will at least indicate that the pump is doing something.

4. Check fan operation. Remove the cover from the ALDL under the driver's side of the instrument panel. Connect the "A" and "B" pins with a bent paper clip or something. Turn on the key. Is a few seconds, both fans should run. If not, you have a problem in the fan circuit somewhere.

5. Check the thermostat.

6. If no problems are found, then you need to start looking deeper. There is a quick test that can be done with a sniffer to see if a head gasket is blown. Check for bubbles when the car is running or air in the system. Unfortunately, this is difficult to do with the Vette due to the tank being set away from the radiator.


Don't drive the car until you sort this out. There is a potential for major damage.

PeteL

Agree that some damage has probably been done at those temperatures. Don't agree that DexCool is superior in many aspects, but do agree that it may not be the cause of the problem. GM does not recommend using DexCool in pre-94 engines (think that this may be due to at least seal materials from other posts on this board).

If for some reason your heads are not warped and other damage has not been done, you need to thoroughly flush that cooling system (after finding out what caused the overheat, i.e. stuck thermostat). The type of cavitation and boiling inside the system that you experienced puts you at serious risk with DexCool and leads to gelling from what I have read. A good shop should be able to recommend a good flush solution to clean out the system from any 'stuff' in there. GM also no longer recommends using the sealing tablets.

Good Luck and let us know what happened(s), please.

Pete

GlockLT4

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Don't agree with this one. Dexcool is a superior coolant and is not the source of this problem. I would check the following:

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I am not saying that it is causing the problem... but GM recommends against putting Dexcool in 93' and earlier C4's. I'm just relaying that info. I have the green stuff in mine, and I don't plan on changing it.

vettenuts

Pete,

Statement made based on two things, first the lower Ph of Dexcool over "green" and second the lack of silicates and resulting wear reduction on the water pump. As far as system compatibility, everything I have found to date indicates better compatibility.

However, having stated that, and I am sure you have read the recent GM/Texaco study, I would take a close look at the radiator cap while you are diagnosing this problem. If you need more information on what to watch for with the Dexcool, check the following:

http]//www.imcool.com/articles/anitfreeze-coolant/dexcool-macs2001.htm

89 Bob L

I agree with the above posts. You hav esome work to do. I would suggest you start off with flushing the system and removing the radiator, to clean it and the surrounding area. Check the water pump, and with the radiator out, change the pump along with the hoses. It is a good preventative investment. Check the fans along with the relays. Put the system back together and change the radiator cap while you are at it.
Burp the system.

Dexcool is a good product, however it is not recommended fot all vehicles/years. I do not believe dexcool was the tproblem with your system.

R Cook 92

Well, I picked up a thermostat from chevy yesterday, changed it, (really easy I might add) and I took it for a little test drive, it was night, and cool, so the heat and humidity wasn't a factor... it ran good, right at 194, then I pull in the garage and let it sit to see if it heats up....of course, right back to the 240s. it kept climbing, so It is still in the garage, and I'm thinking my fans aren't cooling it??? shouldn't my fans cool it at an idle???? I did the A to B jumper and the fan kicked on.... I don't know where to start with the fans...???? relay? switch? Short? ECM? on and on... I guess I'll go back to the green stuff... I cleaned my rad about a month ago when I replaced my condenser... so it is free of junk... I did crawl under and look for a big piece of trash, but nothing.... I guess the fans are what I'll start on... I didn't set any codes... I feel like its a needle in a haystack!!!

Any similar problems????
Randy
92 auto coupe.

Camvette

With that test,A to B you had to remove the fan relay? If so then it is your relay not turning on the fans. Replace the relay and see if that turns the fans on. You can also install an over ride switch to the relay.
Or you can do as I did and install an adjustable fan switch and set your own temp to start the fans.

PeteL

Were your fans running at 240*? If they were not running then that could be the problem.

You can test the thermostat you removed by putting it in a pyrex container with water and seeing where it opens - you need to hold it away from touching the container.

Did you refill and burb the cooling system?

R Cook 92

I didn't touch the relay, I havent messed with it... I guess I'll replace it though... do these just go bad??? 89,000 miles...

Randy

R Cook 92

well, I replaced what coolant I lost as I did the thermostat, and I let it run with the surge cap off for a while as I filled it correctly....is that what you call "burping" it?? if not let me know,

Randy.

PeteL

Randy

You said that the fans run when you connect A&B on the ALDL, this is good and means the relay is OK, also means that the fans work.

Do the fans come on by themselves when the coolant temperature is 240* as you said in the garage?

I don't know much about LT1's but I believe you have to bleed air from a bleeder valve that is up near the throttle body. Adding coolant at a 50/50 ratio as the thermostat opens and slightly elevated throttle will also help 'pack' the system.

You need to answer the fan question so we can try and send you in the right direction. One thing at a time and you will get there. Don't start throwing parts at it, you need to figure out what is wrong.

Good Luck,

Pete

R Cook 92

ok, ok, ok! Well, I just played with it again. I started her up, and let it warm all the way to 242 deg. no fans. I kicked the a/c on full blast at about 235, still neither fan... shouldn't the a/c always kick on the secondary fan...??? CTS switch? or is there a little fuse under the hood somewhere for the fans???

is anyone still bearing with me????

THANK YOU!!
Randy

GlockLT4

One of the fans should always kick on when you turn the A/C on. This is because running the A/C puts additional strain on the engine and the engineers knew this would cause your engine to heat up more, therefore the fans help cool it.

It sounds to me like something to do with the ECM. Your fan should come on at 228 degrees exactly. If it doesn't, and the fan, relay, and switches are good, then that pretty much leaves the ECM.

Any other recommendations for him?? I'm stumped now.

R Cook 92

what does a new ECM run these days? $100 exchanged?? is there any way to check if that is what is wrong??? All the other functions on the car are perfect. I guess ECM does sound logical... There are no fuse containers for the fans under the hood...I know there are some around the lights... but is there anything of that sort for the fans?

Thanks.
Randy

vettenuts

Randy, if you don't have the factory manual, I can pull the diagnosis chart out of my 90 manual and send it to you. It should be close to the same. As far as the coolant, I still don't think that is your problem so for now I wouldn't touch it. Another option is to hardwire a fan switch and then when you hit 210 turn on the fans, the temp should drop right down. If it does, then the system is operating properly and it is just a fan issue. I sent myself an e-mail to home for a reminder.

As far as operation, the ECM simply grounds the relay to start the fan, so it is possible that the circuit that does this is not working. Another option, if the car runs OK, is to install a temperature fan switch in the driver's side head and wire it to both fans. That is how mine is set up and it works really well.

R Cook 92

I do have a chev service manual, but I can't seem to find too much on fan diagnosis... it is a preliminary manual, but the only sections it doesn't have are transmission, and body...

I had been wanting to wire a manual fan switch before all of this started, So do you recommend this?

I would like to keep all the settings factory, as far as the time they kick on... So I don't like the idea of wiring both fans to the CTS... I just want it to be normal again...

I just need the manual switch for the staging lanes... other than that I hate to screw with the wiring...Anyone done the manual switch??? how to?

Vettenuts: if you have a diagnosis chart in your 90 manual, please send it on over... Anything helps! Thank you....my address has changed: my93zr1@aol.com

THANK YOU ALL!!
Randy

Nathan Plemons

Even if your fans are not coming on at all, it should stay cool at highway speeds. The fans are supposed to shut off when you exceed 40 mph. It really sounds like your radiator is not doing it's job right. It could be clogged or blocked up front. The best advice thus far is to check all your hoses and find a way to make sure your water pump is doing it's job. Make sure you have ALL the air out of your system, etc. The fans not coming on is a major problem, don't get me wrong there, but the car should be able to maintain it's cool at cruising speed, if not then you have a more serious problem.

R Cook 92

Nathan, the car ran at 194 deg at 45-50 mph, it is perfect at moving speeds, it just heats up at an idle....

All hoses were replaced in feb. they should be fine, no leeks or anything....
Thanks.

Randy.