RyanPerrella

yeah, i wish i had this thread 2 weeks ago, i replaced a thermostat and it ran at the same temp. A shade below the last white line and with ac and in 100 deg weather a shade over.

I remember reading in about 2003 that ferrari had released that their F1 engines had an operating temprature of 230-240 deg for those that care about what an F1 car runs at.

PorKen

The hotter the engine, the less heat energy is wasted heating coolant.

Hot engine, cool intake!

Sab

It's not the engine or the thermostat in most cases. It is the old radiator.
Leave the stock thermostat but make sure you have a fairly new radiator.
A new radiator will allow your car to run 20% cooler. Then once you have the cooling capacity you can change thermostats to change the desired temperature.
If you are running on an old "clogged" radiator your temperature will increase at the track because you are at full cooling capacity. If your radiator is new the temperature will be determined by the thermostat.

Sab

My GT does not reach the second white line, not even on the track. And it runs some positive manifold pressure...

Cameron

Based on a tip, I got a deal on a new in the box BEHR rad (sub $500) and since I track my car, I went for it. I used to think that it was normal for the car to run at or near the right most white line. And to run almost red on the track. Not any more. I was at Homestead DE two weeks ago in 90 degree South Florida June heat and on the track the car ran just over the white line with the new rad, no where near the red like it did in the past. In normal driving with A/C on, near the middle of the guage.

One thing that I found was that my original rad was down about 15-20% on capacity due to blockage from leaves and debris that had found its way inbetween the A/C condenser and the rad near the bottom of the rad. I could not see this before the old rad came out. Had I known, I would have probably tried to clean the old rad out of debris first and then checked to see if there would have been a difference. I suspect so.

Anyway, I am very happy now to be near the middle of the guage under normal driving in hot south forida with A/C running and I am even happier to be able to run hard on the track and be just above the right white line. I agree with Sab. If you are always near the right white line, you are down on cooling system capacity. Pull your rad, check for blockage. If that doesn't fix it, get a new rad.

Jim R.

My boosted '89 GT runs between the two white lines, has never gone over the second one with the stock t-stat and a 3 year old behr radiator. That was the same before the SC.

Jim

Ispeed

I have a different radiator than stock: it has a modern Behr core that has 4 coolant passages front to back instead of one thin one like stock, and is 1/4" thicker too. It has the stock end tanks with a separate piece that crimps the tanks to the core (made of copper), and it uses the stock top and bottom pieces of the radiator to catch the fan shroud.
It works well and seems to run at a cooler temp than the old original, but I have no temp data to support that. The radiator guy estimated 30% increase in cooling capacity. I have both belly pans and good electric fans.
My '87 has a different looking guage than the '89 and newer cars, and the later ones had temps marked on them as well.

dr bob

928andRC51: Got more info on the radiator core you used? A part no or application info would help a lot.

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My car runs three needle-widths below the third line in most all driving. I speculate that this is the thermostat-open point give or take. Yesterday, in 100+ temps with the AC cranking, it was cruising at one- to two- widths under that mark. For the last two miles to the house, uphill pull, and in first/second the last half a mile, it crept up to just above that third mark. For only the second time since I've owned the car, the cooling fans stayed on for a couple minutes after the engine was shut down. First time was 7 years ago, after a hard 80+ pull from the California central valley, up the Grapevine hill to Fort Tejon, in 110f heat. So I know that the new manifold switch is working. And the radiator is spilling a lot of heat into the engine bay...

Gretch

I have the same experience to report as Jim and Dr Bob. I clime "hills" where I live and that is the only time the temp moves up close to the third white line...........