Now that it's summer time, I'm having some overheating issues again with the vette. I have a fairly new aluminum LT1 radiator (1.5 years) sealed around the edges, dual electric fans sealed to the radiator, a 160* stat, and a Meziere electric water pump flowing 35 GPM. There are no leaves/junk obstructing the radiator. For a while the temp sits at 160 and then slowly starts increasing. If I'm at steady cruise on the highway, the temps seem to level off at about 200. However, if I pull off on to side streets the temps will jump up near 220 which is when I pull over and shut it down.

This is not the first time I've had heating problems. Originally I had the stock mechanical LT1 water pump, the same radiator and fans (all unsealed, however). I would experience this overheating problem at idle/low speeds, but on the highway I would actually run a bit on the cool side. When I took my heads off to get ported, I made the change to the current cooling setup.

Any ideas on what is causing this problem and what I should do to fix it?

Thanks

 

FWIW ... the temps you're seeing are not much different than what I always see in my '96 (LT4). And, I saw similar temps in my previously owned '96 LT4 also.

 

Sounds about right. What temp do your fans come on?

 

My fans are always on.

At what temp do you risk blowing your head gasket/etc.?

When my car gets that hot, it starts running kind of crappy. I have converted the LT1 to a carb'ed setup, and the fuel starts boiling I think. This is even with a wooden spacer. If these engine temps are normal, any idea how to fix the fuel issue?

 

Not helpful, but I know at over 320* it will happen. I wouldn't be speaking from experience now or anything :eek: :eek:

 

timing??
cylinders leaking compression thrugh coolant passages (head gasket or intake gasket)?? (not likely but possible)

My car (84) does the same thing even with the fan on all the time, not that hot tough, I've done pretty much everything and seems ok (?).

On my car, I'm suspecting a clogged radiatior (it's not even alluminum), since there's no white/blue smoke and it's not loosing any coolant.

:cheers:

 

With a 160 t-stat and electric fans set at low temps this can't be right !! I run a 160F t-stat and never see temperatures higher than 190F water and 200F oil even in city traffic and 90F ambient temps.........

 

This is how I'd hope mine to behave as well. Any ideas on what might be causing my problem?

 

Overheating is caused by two things: 1) Starting the engine. 2) Global warming. :nopity

Drink a beer to cool down. :cheers:


[Modified by McShagger, 3:22 PM 7/13/2003]

 

First, your temperatures aren't very high as C4's in the summer time go. My 87 runs 195 over 35 mph (no a/c, 195 stat, Stewart waterpump, everything else stock). At stoplights, I use my toggle switch to turn on the fan and the coolant goes no higher than 200 and drops when I get underway. First I would replace the 160 thermostat with a 180 because it cannot do anything but stay wide open and this allows coolant to flow so fast that it will make foam from the small amount of air in the cooling system and foamed coolant is a very poor conductor of heat. Make sure you burp all the air you can out of your cooling system and have 1/2 your overflow bottle full. A 180 thermostat will partially close and slow the coolant down IF your radiator can get rid of heat fast enough and I think it can. With no foam, your coolant will conduct heat better and over 35 mph you should be able to run 180-200. At stoplights its a different story and 220 F won't hurt your engine and the owners manual says shut it off at 260 F.
Now if your carb starts acting up at 220, then I think your options are to get a bigger radiator that can transfer more heat than the stock radiator. Also, I don't know what my Stewart flow rate is, but it could be higher than the Meziere and higher flow rate allows higher heat transfer.

 

If you can keep your Vette under 220 in Texas while in heavy traffic, you are doing good. 190-200 on the highway is acceptable. Your situation is part vehicle design and part geography. You aren't going to blow any gaskets at these temps. The fan on my 84 doesn't even kick on until around 225, and goes off around 205. Yours sounds normal.

 

Mine has seen 270 on several occasions with no ill effects. I talked with Doug Rippie last year, he said they would regularly race at 260.

Just a thought, do you have the steam vents connected to the coolant lines from the back of the cylinder heads?


[Modified by John Row, 11:10 AM 7/14/2003]

 

Here in Vegas 225-235 is normal midday on a hot day...and its been 110-115 all week.... :reddevil

And I just installed low tem switch, new aux fan relay and pulled and cleaned radiator....still runs 230 here.....sux.... but the cooler weather is on the way. Only going to be 105 next week. :cool: