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

 

just get a bigger radiator

 

I had a similar problem with my 94 LT1, and i ended up replacing the entire cooling system(radiator core, water pump, water pump switch, thermostat, hoses) before i gave up and at the last minute changed my fan relay switch. Ur fans might be coming on, just not all the time. It also might explain why it cools good on the highway. Give 'er a try.

 

My fans are always on.

 

The only thing i know left to do is check and see if there is water in ur oil.. u minght have a cracked head gasket. Go and to a shop and have them see if there are abnormal oil burning from your exhaust.

 

Seeing as that you are not stock, you may just be overwhelming the cooling system at low speeds. See if you can crank your fans on high, if they are not already.

You could try some Redline Water Wetter, I've heard good things about that stuff. Also try adding more water into your mixture, so you have 70/30 water/coolant. Antifreeze lessens the heat dissipation qualities of water. Or something like that

 

I had the same problem after I put my blower on, heres what I did: Drained coolant and filled with water only + a bottle of water wetter. Also, make sure you bleed the air out of the system using both the bleed screws.
My car was at 230* on the dyno, after the change, it didn't go over 200*.
If that doesn't do it, drill a few holes in that 160* stat.