Theres just air in the system. If the T-stat was stuck open the car would be cooling perfectly fine. The purpose of a thermostat is to stop coolant flow to allow the motor to reach proper operating temps. If the stat was stuck open coolant would flow consistantly keeping the motor cool. Ive have some cars that require a few WOT punches to get all air out of the system. But first you can accomplish the same thing by holding the throttle at 2500rpms for a bit to help spin the pump faster. Position the *** of the vehicle higher than the front. Leave the cap off of the radiator while you let it run. And buy this..... it will be your best friend.

http://www.napaonline.com/NOLPPSE/(S...000_0089098696

 

well i got a new cap for it and i have dran it like three time i think it might be the radiator myself but i flush it. so im going to try a new radiator thanks everyone

 

Well Since this started to happen after you put the cam in and it happens when the car is under a load my guess is that the tune could be off and be a bit on the lean side.

 

LT1 porsche If the Tstat was stuck open the coolant would cycle too fast and not get enough time in the radiator to cool, making the car overheat. If removing the Tstat would make the car run cooler why wouldnt you take it out and keep it out then, wouldnt that make the car run better?

 

Not exactly, there are a bunch of old cars running with no thermostat to keep the radiator fluid constantly moving. I was considering doing this, but the electric fans would stay on constantly. On old vehicles, the fan is connected to the crank belt so it is always on.


P.S. LT1porshe, I love your Avatar!!!~

 

well it still getting hot after i did the radaitor so i donno maybe my tune off so it going lean when i drive it around i donno so im hopefully going to the dyno tomorrow so maybe that well tell me something

 

What coolant/water mix are you using. I always go 75% water/ 25% coolant with a bottle of Redline Water Wetter. Maybe the mix is off. It could be in the tune as well. If nothing else checks out. See if you can get someone to log your car to see what it's doing. I've seen to much timing to not enough fuel make cars run hotter.

 

Removing a thermostat or a stuck open thermostat DOES NOT make a car overheat. On a lot of cars with difficult cooling issues used to be resolved by removing the thermostat to allow coolant to flow consistantly at all times to keep the coolant traveling through the radiator where it is cooled off. To the O.P........ feeling the upper and lower radiator hoses. Are the both hot?

 

I completly agree! T stat open will not make it over heat. In modern cars the T stat has a certain diameter for flow amounts. Here in Fla I drilled little holes in my T stat. I feel there should be constant flow. My car is warm in 2 min.

I've seen a impelar fin break off and it was fine at ide but not under a load. We replaced EVERYTHING even thought it was the head but it wasn't. Over heating is a matter of check list.

You could try running the heater in the car and see if temps go down. That could tell you the Rad is bad.

Also keep in mind the LT1 rad is almost double the size of the LS1. Most people may not know this.

 

^^^^^ It is a LITTLE bigger. LS =7/8" and LT = 1".

 

I didn't measure it but it did look like 50% bigger. My temps did drop a bit over the LS rad.

 

Some obvious things to check as a result of recent changes you made that would be effected as a result of your changes (underdrive pulley).

You installed an underdrive pulley. As a result your waterpump will turn slower now than before. If your car used to run 190 with a 187 T-stat by default the temps will raise because the smaller underdrive pully spins slower spinning the waterpump slower as well. In hot climates 200-220 is not unreasonable in city driving but should back down to 190 on the highway if the air dam is still on and hasn't been removed. Since you have removed the AC you should be getting maximum ambient air temps flow through the radiator compared to heated air that has passed through the AC condensor if the AC is running.

Did your shop install the corrrect belt length or is it too long and might it be slipping?
Did they torque the bolt for underdrive pulley correctly or is it slipping at high speed?
Did they use a new bolt or the same bolt?
Was it a new under drive pulley or used and possibly defective?
Is the upper belt tensioner moving freely?
Is the belt routed correctly over the water pump pulley (black round drum)?

You removed and reinstalled the radiator.

Did the shop attach the steam vent line to the correct tube on the radiator? Or is it attached to the overflow tube? A shop criss-crossed mine. This will cause overheating at high speeds as the steam isn't being returned into the radiator to be condensed and recycled. It is stopped at the radiator cap inlet by the radiator cap.

Did you replace the cap on the new radiator? Is the gasket defective on the cap?
Is the wire attached correctly to the temp sensor on the radiator just underneath the radiator cap. It twists on and is locked in place with a spring wire.
Was the temp sensor clean or surrounded with caked and solidified DexCool?

By default in city stop and go driving the air dam isn't as effective as it is at 70 mph. Is it still on, not broken, or been removed?

You changed the under drive pulley - I would check it first.

One last thing: You must compare apples to apples meaning that your coolant mix ratio has to be the same if you are comparing temps before and after your changes. For example a 75/25 water to coolant ratio will draw more heat out of the heads than a 50/50 water to coolant ratio meaning you engine will run cooler with a 75/25 ratio. So if your coolant ratios are not the same before and after combined with the affects of the smaller under drive pulley it is reasonable to expect higher temps now than before.

With a 16-18 lb cap a 50/50 ratio will boil at a much higher temp than a 75/25 ratio. The downside is that you might have freezing in the winter dependent upon the climate in you live in so you might not want to run a 75/25 ratio.

 

If the engine is overheating at speed it is usually one of two things - insufficient coolant flow or insufficient air flow over the radiator. Replacing the cam only involves removing the water pump and removing the radiator (as far as cooling system goes). So unless you left a wrag or something in the cooling passage of the block, or have a piece of cardboard stuck in front of the radiator, the likely problem is air in the system (or the thermostat is bad). I would start by removing the cap, start it up and see if the coolant starts to flow when it warms up - especially watch for coolant running from the tube that connects to the crossover pipe from the heads. If it doesn't - pull the the themostat and check again, if it does, top off the radiator with coolant put the cap on shut it off and let it cool down. Then take the cap off, bring it up to temp again put the cap on. That should remove any air. BTW - your air dam is intact - yes?

 

as far as i knew 200-220 its normal the thermo opens at 180 but fans dont kick on until 200 and second one at 225 or when the ac pressure gets above 245 kpa