nikkev

We have a '95 Trans Am, and we are slowly but surely saving her from a previous owner. The motor is great, but everything else needs work. The car is camm'd with roller rockers (not sure what size) and I ""THINK"" the computer has been re-programmed because the fans come on at 160*, or shortly after you start the car. Something I noticed the other day was that our temp guage wasn't working, so I grounded the wire and the guage needle went to full temp. I replaced the temp sending plug and now I am not sure the new one is working. The engine temp never rises above around 162-165* on the guage. I thought the guage was still broken, so I opened the radiator and dropped a thermometer in there. Sure enough, the coolant temp in the radiator was showing 168*. I have 2 questions;

Will a thermometer in the radiator show an accurate temp of what the coolant in the engine is at?

If it is an accurate measurement, will it running this cool hurt the motor or performance?

Thanks for any help you can give. We are currently moving 400 miles away and we will post the story of the car once we get settled. Thanks again!

Kevin

96 TA

Kevin,

On my 96 TA when i first bought it i had the same issue. Thinking my T-stat was stuck open i bought a new one and when i removed the T-stat housing it turned out that there wasn't even a T-stat there, just the gasket. Not saying that's what is up with your car but at least it's a possibility.

nikkev

Definately a possiblity with this car. Not to tell the whole story, but here's 2 fixes we have done already:

-ABS light on.........plug on passenger side wheel was un-plugged.
-Cruise Control didn't work.........ground wire was just hanging.

We're finding all kinds of things like that on this car. And we've fixed most of them. Once I get my computer set up in our new house, I'll post pics of the 2X4 bumper setup it had when we bought it......

And..... if I don't have a thermostat in there, what temp should we get? Apparently the fans come on at around 160*.....

96 TA

I think the fans come on too soon. Id run a 160* T-stat and have the fans come on at 175-185. If the fans come on at 160* and the car never gets hotter then 168* id bet there is no T-stat in there at all.

96 TA

but to answer your question id put a 185* T-stat in there.

Injuneer

Stock t'stat in an LT1 is 180*F. No reason to bump it up to 185*. The 160* works well, with the correct fan on/off temps, and a tweek of the iginition timing. AS you've already noted, his fans are programmed to come on too low.

nikkev

So stock thermostat until I can get the car re-programmed?

Injuneer

If you put a stock 180* t'stat in with those low fan on/off temps, its going to be a mess. The t'stat won't even begin to open, it will overheat, the t'stat will crack open and the fans will run all the time, shutting the t'stat right back down.

96 TA

Thats what i would put in for now until you get your fans reprogrammed, but ultimately it's up to you.

I run a 160* and have my fans come on around 195* and off at 185* some people have there fans come on sooner. Ive never cared about my motor running super cool, im happy as long as it stays under 200* you'll just have to do some searching to find out what you think will work best for you, and thanks Fred for clarifying what the stock t-stat temperature is.

96 TA

thinking of it that way makes sense. Do LT1's run better cool or with a little heat in them like say between 185-195* VS 160-175*?

I was thinking they were happier a little warm and suggested a warmer t-stat so it could heat up some. If his fans come on at 160* i don't think they will ever shut off no matter what t-stat he runs. At least as long as it's July and 90* or higher outside.

Injuneer

When we set my engine up an an engine dyno, we found the best results with a 195* fan on temp, along with the 160* t'stat. But that's a specific, modified engine.

Coolant temp has several impacts. The more heat it removes from the combustion chamber, the more it reduces power. Its the heat that stays in the combustion chamber that gets converted to power. So hot coolant increases thermal efficiency.

BUT.... if that coolant is also heating up the air that is entering the combustion chamber, its costing you power. Then there's the issue of spark advance. Lower head temps allow a bit more timing advance. That MAY net you more power.

So its a tradeoff - and the LT1 dyno tests seem to indicate that the 160* t'stat, along with revised fan on/off temps and a couple degrees advance, can be good for as much as a 10HP gain, indicating that the colder inlet air and added timing advance more than offsets the lost thermal efficiency.

96 TA

Good info! Thanks again Fred, i learned something

nikkev

Thanks very much to both of you! After we're moved in and settled, a dyno tune is in our near future so we'll make sure to get the fans re-programmed.