I recently had a new ls3 longblock installed in my 2008 corvette. It's an a6 Z51 car with a aftermarket transmission cooler and a 160 tstat. I've been monitoring my oil/coolant/trans temps and noticed they are quite a bit higher than my old motor.

Old motor 24200 miles
Engine Oil temp: Never seen it go above 245
Coolant temp: At the track in the staging lanes high of 215-220
Trans temp: High 190s drag racing

New motor has 1100 miles
Engine Oil temp: 268 after a few freeway pulls in 60 degree air
Coolant temp: 230
Trans Temp: 220

On the new motor with the 160 tstat the coolant temp always gets really hot when I turn the car off. If the car was sitting at 230 and i turn it off for a couple mins the coolant temp goes up to about 250s. The old motor never did this. It does make sense that the coolant temp would climb as there is no coolant flow. Just confused as to why the old motor never did that.

For the coolant temp it seems to me that the oil is causing the raised coolant temps. On both the old and new motor cruising on the freeway at night it would stay around 180 regardless of oil temp. So I guess this leads to why is my oil temp so much higher than the old motor. I've done back to back pulls with the old motor and never saw above 245 degrees but the other day cruising around town with the new motor it got into the 240's.

It all just seems hot to me unless im just over reacting as it is different than before and would really not like it if something breaks again. And if my oil temps are too high what are my options as far as oil coolers go. It seems the z06 cooler is what most everyone does but I have my transmission cooler mounted in front of the condenser. For you auto guys out there running a oil cooler and a transmission cooler where did you mount your coolers?

 

There has to be more friction in the new shortblock somewhere to explain the higher temperatures. I'm not claiming that it's harmful - it could be that you have tighter clearances in the new shortblock compared to the previous one.

You didn't mention any change in oil pressure. Have you seen that?

Does the engine seem to rotate slower when starting? What about throttle response when there's no load on it? Does it seem to freely rev like the old one when it's in neutral or park?

I would send a sample of the oil out for analysis to ensure that you don't have any significant and unusual wear materials in the oil.

Steven

PS - What's your A6 cooler setup? I've been considering that for mine.

 

I went from an LS2 M6 to a 416" LS3. Upgraded to a Z06 oil cooler, a Z07 radiator and 5W30 Red Line oil. Water temp is around 200 and oil is 210 on a normal 70 degree day at 70MPH. On cold days, I actually have an insert to block air going into the grill to get oil temp up. The additive package in motor oil works at 100C, so I needed temp.

Don't laugh, but what oil are you using? if you are using a heavy oil, it may be trapping the heat in. I work for Red Line Oil and they are in Benicia, not far from Tracy.

 

Oil pressures are the same but as the heat rises the pressure drops thats when i noticed the heat issue. Im running moble 1 5w30 synthetic. Pressure at idle is around 24-35psi depending on oil being hot or cold. Starts the same. Revs the same but this new motor is definenetly stronger so i guess the clearances are tighter. My old motor was kind of a slow pig when it was stock. 12.8@113 was the best it could do. I can already tell this motor is stronger. Im going to take it to the track this wednesday to see what it can do.

Im just running a ebay cooler i got for about $35 bucks. Had it on for about 6 months now. Works alright for a cheap cooler. I may end up going with a bigger one deending on trans temps with this new motor.

 

you will notice temps will drop after the engine is broken in this may takke quite a while with synthetic oil. my last one stayed high for about 20,000 milles

 

Is it a stock LS3 or has the compression ratio been bumped up a bit with the new engine.

KW

 

Bone stock ls3 longblock. So it seems as the motor breaks in over time the temps should slowly drop?

 

That was my experience the last time

 

Alright we will see how the temps are at the track. Any guesses on times? Last motor did a 12.8@113 bone stock on street tires. Has a ss4000 stall in it now but going on street tires. Stock other than the stall. 285 street tires.