solaris_vii

let me start with this is not in a vette, but a 94 cadillac fleetwood, so if i should post this in off topic let me know but i thought this might be a good place for answers. I just inherited this car, and was driving it home yesterday not really knowing what might be wrong with it. on th ehighway i got stuck in stop and go traffic and the temp light came on (no gauge in this car, ughhh) and didnt go off once i got going again. i kept driving and got off the highway and it stalled out while i was pulling into my driveway. got lucky. would not restart then but i didnt try long, when i tried today it did start up and still drove fine, but im worried about any damage i may have done. it is an iron block with iron heads, so i feel a little better than if it was a vette with aluminum heads. what should i do? Im going to change the oil tomorrow, and see if there is any coolant in it. i should add it was pouring steam out of the overflow tank cap, and in this set up there is no radiator cap, just that cap. so that may be bad, im planning a good flush and new thermostat next. should i do a compression check or anything like that? it still runs ok. sorry for rambling, open to any ideas/criticisms (flame suit on)/critiques you may have. thanks guys.

JAKE-SON

Unfortunatley i have overheated my 96 lt1 401 ci with aluminum heads several times. Im talking steam out the reservoir, temp light, car shut off, pegged analog gauge, everything. To make a long story short, i am not worried, i have pulled the heads a few times since for new spings and polish, and then a port a second time. Car is running strong and i havent had any issues. However, everything has been rebuilt and forged. I believe the lt1s are designed to shut themselves off to prevent damage.

Ryan

solaris_vii

thats great to hear, im not as worried now. im changing the oil today and i guess i will go from there, im thinking a complete flush of the cooling system will be my next step. thanks for the reply!

Dave68

Does it have an electric cooling fan? I suspect that if it does, the fan switch is not working and needs to be replaced. Also check to make sure nothing is blocking or partially blocking air flow to the radiator - like a plastic bag or sheet.
With a cast iron block and heads, your overheating incident most likely did no damage.

solaris_vii

i checked the oil today and it looked fine, that is a great suggestion about the fans (it does indeed have electric fans) ill have to checked that. i refilled the overflow and it took about 2 gallons before it was at the full mark, then on the drive home it poured out steam again and the temp light came on but did not shut off this time. i think my next steps are to make sure the fans are kicking on and maybe take it to get a coolant flush and see if anything is plugged up. i checked all the hoses when i went to change the oil and they were all warm except the one returning from the heater core. i did have the heat on. i suspect my clog may be in there, but it still doesnt explain where my coolant is going. thanks for the help so far guys!

VetteMed

If it is overheating while driving, it's not the fans.

LT1 does not use a fan "switch". The PCM turns on the fans.

Dave68

If I read his description, correctly, the car was NOT overheating on the highway. It was only after stop & go traffic that the engine started overheating.
That's a classic fan-not-working scenario.

solaris_vii

well, ill tell you this, drove it again and just driving around it started shooting steam and temp light came on, im kind of starting to suspect the water pump, its like nothing is circulating. is there a fool proof way to test that? i touched both hoses and they both seemed warm but i guess that could be misleading

JR_VETTE

Check the relay's for the cooling fans. I just had to replace one of mine on my 2002 Camaro SS. Low speed relay was defective, and luckily high speed was still functioning. If it had gone out, I would have been in the same boat.

JR_VETTE

Go get one of these if you don't have one :


Check the temp going in/out of radiator. Might be something as simple as a defective thermostat. If it's hot coming back out of radiator, and fans aren't coming on, well you found your issue.

I wouldn't do to many more of these tests though. If you do, don't overheat it again, just run it to operating temp. That should be enough to get an idea of what's going on.

solaris_vii

no im not going to drive it anymore until i figure it out lol i might have to get that temp sensor thats a good price for that tool

solaris_vii

well, took it apart and found the issues. the blades on the impeller had rusted away, so it was spinning the water pump but it wasnt doing a damn thing. and the gunk and rusty coolant i drained out of the radiator was just crazy. i will probably have to flush it out again before winter. but, its running well now, no overheating, also repaired the wire to the knock sensor while i was down there and no check engine light either! i broke the bracket to the air pump though.... oh well, it still holds, should be ok. thanks for all the suggestions guys, car is back on the road!