I just got my car back Friday after having it in the shop for a new stroker motor, trans and rear end. I also installed a new Dewitts radiator and trans cooler. I noticed on the way home my temps climbed to 230* in traffic so I shut of the AC and it came down to 220*. I also have a 180* thermastat. Today on the way to lunch I look down and my engine temp is 230, 235, 240, 245, 250!! this is on a side street at a light, so I swung into a parking lot and it was boiling coolant out and the fan was not running. After sitting there with the car off looking around for a few seconds the fan kicks on. I start the car and the temps drop to 220* real quick and everything seems fine. On the way back to the office it starts doing it again and the temp is 230* when I get to the office. After it cooled down a little I went out and started the car with the AC on to see if the fan would come on and it was off. after screwing with the wires and burning the skin off my arm the fan comes on and it kicked a small rock out. Could this have been the problem or do I have another issue? The shop said it could be the fan plug going bad, they said it is a common issue. I do not like taking a brand new engine up to 250*. My oil temp was 230* and my trans temp was 211* Tomorrow morning I am going to drop it off at the shop so they can go through everything. They said if it acts up on the way home I should turn off the ac and turn on the heater. what do you guys think?

 

Did you get the air out of the system? Also, when does the tuner have the fan turn on?

 

Most go with a 160 thermo.
You shouldnt have those high of temps if the car is moving at normal speeds on the road even if the fan isnt working properly. As said, it should be checked for air in system. A blockage of some kind might be so,mething to check.
Do you trust this shop?
If you start overheating turning on the heat full blast will help somewhat. Turn the vent so most of the hot air goes out the windows

 

How do you check for trapped air?

 

Just a thought... look up "Casper" they make a switch that just a plug in, & you can turn on your fan either "Hi" or "Lo" even with the engine OFF..

I have one that I use a lot at the track, with the engine "off".. however you can (I have) turn on the fan in traffic, I have a 160 T-Stat. and my car never goes over 195.. but I also had the computer tuned to race, they (Cartek) or any tuner can set you fans to go on at 192 deg.

The only thing you have to be careful is not to forget the fan in the ON position when you park and are going to leave the car for an extended time...

I connected a small RED light that will go on if I manually turn on the fan.. (I'm getting Old & Forgetful)

 

Definitely get heater running at full blast since it is just a small radiator runs on the same coolant.

I doubt air is the problem, it rises to the highest point of your cooling system anyway and doesnt block coolant. Looks like that little rock might have done it. Your fan should be wired so it turns on when AC is on or coolant reaches certain temperature. If it is not running then something is wrong on the fan side.

 

Put a 160 t-sat in. The stock is 187.

 

WOW! Good info, thanks!

 

Also, here is a good thread about the 160 t-sat.

http://forums.corvetteforum.com/c6-c...y-getting.html

 

The fan should have been on well before then. That's your problem. The thermostat is not an issue. Your stock thermostat (if functioning) is wide open already.

 

See item in red ...... needs to be addressed

 

A trick to get air out is to remove the small hose coming from the block (crossover pipe from head to head) to the radiator and blow in the reservoir spillover tube with the reservoir cap still on. Keep the engine off. This will slightly pressurize the coolant in the block forcing some, if any, air bubbles out. First time I had to refill the coolant I had a similar issue (temps up to 255+ F) and luckily got a big air bubble out using thius method.

Another idea is maybe a bubble made its way to the pump and it isn't moving any fluid anymore? This manual air purge method could work for this as well. Its cheap and easy to try, but gets a bit messy. Disconnect from the engine side and see what happens.

Good luck.

Sean

 

most decent t-stats will have like a little purge valve in them
that goes upwared, if they dont i personally drill a small hole to help with the air purging
once way to get the air out is to pour in the fluid slowly and having the front of the car up high
at the shop we use the two front legs on the lifts to get the front end up
also squeezing the rad hoses helps move the fluid and air out
but since your fan was not working due to a rock you should be ok
your AC, especially at idle should have come out warm or hot
that is one indication of no airflow

 

Found the problem, the plug for the fan failed. The shop said it is pretty common for the plug to melt around the power pin and that is what happened. They are going to remove the melted Delphi plug and replace it with a new one.