H2

I just bought a new thermostadt (Porsche/Wahler). The PET shows different thermostadts:

928 106 129 16 (-89)
928 106 129 17 (90-)

My 928 is the '88S4 but the thermostadt I got is the 83 degree 928 106 129 17 (90-) which appears to be made for the 90 MY forward.

I've had some overheating and I want to get optimize my cooling. There must be a reason Porsche made two different thermostadts.

What's the difference?

Thanks,

H2

PorKen

The 16 is 75C. The 17 supercedes the 16 for all years.



The same thermostat design is used on other German engines. I would like to find a 92C part number, and try it combined with a intake/head insulator.

H2

Gracias, PorKen. Now I'll go out and install it.

Harvey

Glenn M

Harvey,
There is a seal behind the thermostat that usually doesn't get changed. Unless you know it has been changed you should do that also. Could also be part of your cooling problem.

Glenn

H2

Thanks, Glen,

The inside seal was still in like new shape. What looks suspicious is that the older thermostadt (Made in Germany, but not Wahler) had a smaller "plate" that was getting stuck in the seal. The new thermostadt has a wider plate that will not do that . I've tested it and all looks well. I also cleaned out the block. On Monday, I'll have it back together for a test run. I'm making a couple of small adjustments on the new radiator (custom made in Portland, OR. Based on Devek Style...only better...thanks to Dr. Ott's advice to the builder). It's a 1/4" thicker and that makes for some modified fitting.

I'd read in some other posts on Rennlist that, for some reason, the 75 degree thermostadt wasn't optimal for the 928. The former unit was 75, the new one is 83 degrees.

Little by little I'm working out all the kinks. Diagnosing the hard starting was a complicated one (but will be simple the next time around). Starts immediately now, even after 3 weeks sitting.

All it needs now is a nice Strosek Wide Body

Thanks, all.

Harvey

PorKen

Interesting. Maybe this was the problem with my '86.5 when I bought it. It would hover at just below the top white line, but rarely went any higher.

With a 83C, the needle is usually just below the midpoint of the two lines, and a 75C was just above the first line.