I just bought a 1993 and in traffic it overheats and starts running bacd, almost to the point it stalls. when not in traffic it starts to cool. it gets almost to 245 or so.....I have no check engine light or other indications..... can someone help??? I am new to vettes ....thanks.... Todd

 

What I do when mine starts to get hot is to turn on the heater. It seems to activated the cooling fan which in turn cools the engine down.

 

First, clean out the air intake system. Your case sounds severe. I'd recommend removing the upper radiator shroud completely. You're going to find a lot of crap in there. Hell, Jimmy Hoffa might even be in there. Do a thorough and complete cooling system flush. Verify that your fans are operating properly, etc., etc. I'm surprised that your red "check gauges" light isn't coming on at 245 degrees. If it hasn't, it's not far from it.

 

Below you will find my first post on my 86, in addition just today I swapped out the repaired radiator for a brand new one and changed out the a/c condenser as well while I was in there( could hardly see through the old one) seems to have helped with the high speed overheating but still over heats at an idle, next weekend I am going to double check the timing and readjust the valves, and I am now looking into maybe the oil cooling area as the oil temp is running 25 degrees hotter than the coolant temp may be a problem there if I get it figured out before you do I will let you know I would hate to see anyone go through the time and money I have so far to no avail! Good luck!

Just joined today major wierd problems here, want to get the a/c working but need to figure out my cooling problem first as it seems to overheat even faster when running a/c, seems like an air flow problem kinda cause over heats fastest when idling, but will also over heat if going too fast ( just takes alot longer) seems to like 33 to 65 miles per hour and is fine in the cooler months. but in the summer I cant drive the car! I have a new motor new 6 speed tranny, new thermostat, new hoses both primary and aux fans are new ( high flow cyclone fan in front) new heater core, sent the radiator and condensor out for test and repair ( my problem might be here but not sure) maybe they closed off some cores? any help would be greatly appreciated I am sure I either did ar tried more but not coming to mind at the moment oh I did try the timing also, oh and I have had the car 4 years and have since did all the above things to the vehicle but this car had the same problem when I got it ( bought it in winter time of course! ) so didnt notice a problem till the next summer anyways nothing I have dont has changed a thing no better no worse not even enough to notice a slight change, wierd huh? thanks again for any help!
P.S. dont know how hot it will relly get but doesnt want to ever stop climbing, after putting an correct radiator cap it seems to blow out coolant at about 250 degrees (before was 240 degrees) SO if 232 degrees is normal operating temperature if I shut my car down at 232 degrees it will climb to 250 degrees and overflow the reservoir before it starts cooling back down, oh the primary fan system quit working so it is wired to the key could it be that the fan isnt running anymore after I shut the car off that could cause it to keep climbing? or do the fans supposed to run when the key is off?

 

P.S. thought I would also mention that at 250 degrees I still have no check engine lights either, and I did check the engine with a laser thermometer and it is reading within 2 degrees of what the dash gauge reads.

 

from other replies on overheatin'...

Could be just a lotta' bug jam in the radiator - horseflies, mosquitos, lizards, deer, flounder, ya know...

Seriously, get a hose blowing through the fins...

Get a thermometer in the heat duct, early in the morning, warm motor, heat on,tomake sure you got flow in the heat core. Then go from there...


Water pump, water flow, thermostat.

Here's your problem:
1) Your water pump is bad.
2) You have flow blockage.
3) The thermostat is bad (same as blockage).

Cold motor. Drain and recover your coolant. Put your garden hose in the coolant hose in one place. Disconnect the coolant hose in severalOTHER places, ONE AT A TIME, to check for flow. Observe also for'jam' of any sort.

YOU WILL NEED A FLOW SCHEMATIC FOR THIS, TO MAKE SURE IT'S COMING OUT WHERE IT SHOULD. A BLOCKAGE WILL MAKE IT COME OUT IN THE WRONG PLACE. I THINK HAYNES HAS IT.

Before puttin' back in your coolant, get the residual tap water out with a shop vac. You will afterward still have air in your system. If the TPI doesn't have a air bleed nipple, get on the highway, WITH HEAT ON!!! This should bring up the air. Check on a COLD motor.

If this fails, go to a radiator shop. They'll hit your pipes with a laser, and check for in-spec coolant temps to diagnose.

 

Guy's on the hose blowing deal.
Blow from the fan side out or vice versa?
I have a lot of grass in mine so I'm thinking disassembly and get cleaned while it's out.
I guess a super cool high efficiency fan might be in order for the extreme climate of Texas.
My air dam is in good shape but does anyone make a more efficient replacement?
Oh and guys don't fall for high volume water pumps cause the coolant needs the time in the radiator to cool off before returning to the engine.

 

Ecklers has a few air dams to choose from some are kinda spendy not sure how well they work but thought of going that route myself but probably wont help my problem as I only overheat sitting still. You may have better luck but the supercool high flow fan didnt help me at all I have so many new parts thrown at mine its discusting! Good luck!

 

For reference......

My stock 92 runs ~200 degrees in traffic.

Less (194-196) on the freeways at speed.

 

First does your car have a Hypertech Chip and 180 thermostat? If you live in the southern states...it is almost required if your driving it in stop and go traffic in warm weather.

Second,....your fan is not turning on. Check your coolant fan relay.

If your fan does not come on after it has warmed up, turn on the a/c which by-passes the temperature set points.

The service engine soon light should be lit if the engine reachesover 230F degrees