odonnell

May be a coincidence, but I had nothing but crappy luck with Wahler fan switches on my '83. Literally ~6 months average lifespan, and I would wake up to a dead battery because they would fail open. To this day I have no idea what was happening.... coolant temps were always fine when in use and the fans came on like you would expect. Nothing was obviously wrong with the fan setup. End game was putting the fans on a relay controlled by my standalone, which gave me programmable cooling fan activation as a side benefit.

marc abrams

Mike, I've had bad luck with Wahler fan switches also. But not with the fans staying on but coming on later. Letting the ECM control the fan was a good idea. We just need a ECM controlled thermostat. I wonder if anyone has tried putting a thermostat in the upper water outlet.

marc abrams

I receive both thermostats last week 944-106-129-05 and 944-106-019-00 and took measurements of both with a pair of dial calipers and for all practical purposes they were identical with the exception of the 944-106-129-05 is stamped 80c and 944-106-019-00 is stamped 83c. I tested both of these using a VOM with a temperature probe and infrared temp gun. The 944-106-129-05 should have started to open at 176 degrees. It started opening at 182 degrees. The 944-106-019-00 should have started to open at 181 degrees. It started opening at 188 degrees. With that said, when I got the first thermostat 944-106-129-05 a few months ago it was stamped 83c were it should have been a 80c. I installed it anyhow thinking it's only a few degrees different. Now I have a understanding what's going on. Obviously all 3 Wahler's are defective but the first one was also box incorrectly. Although the 944-106-129-05 is listed for the early water pump (I have the later water pump) I went ahead and installed it. The car's temperature gauge now indicates a temperatures of 90c-95c (194-203). Not exactly what I was hoping for but I can live with that. And although the Stant thermostat I received was also box incorrectly I'm going to try a Stant thermostat next time I need one. One thing I did notice, the Stant not only open when it's supposed to, it also fully open quicker. I don't race so the smaller opening shouldn't be a problem. So what's up with these Wahler products? Usually I just chuck these parts in the trash but this time I'm going to return these parts and hopefully someone will take notice.

Tom M'Guinn

The early water pumps placed the thermostat 4.5mm deep in the big throat opening, whereas the later pump's placed it 7mm deep. At the back of the throat of the water pump, there is a seal for the pump's internal bypass (to recirculate the coolant when cold). The outer end of the thermostat is designed to form a valve against that seal to close the bypass when the engine is warmed up. I've never compared the two thermostats, so not doubting your info, but I would expect the external dimensions to be identical, with the only real difference being how far that rear seal part on the thermostat open/closes to actuate the bypass. When hot, the other sealing end of the old-style thermostat would need to extend 2.5mm deeper (assuming the throat on the old and new are in the same location, which I've never confirmed), so it seems possible/likely that the old-style would "work" in a new pump, but would open 2.5mm less (and therefore flow less) than it's it should, and potentially bind/fail because it wants to open fully but can't. Consider this speculation since I don't have an old pump to confirm, but if this isn't the reason, I'd still have to believe there was some reason Porsche updated the thermostat when it updated the pump. By the way, you can get those Wahler thermostats (new style) in a variety of temp rating, so no need to use the old style just to get the lower temp rating. 944online has them in 71 and 80 for example.

marc abrams

Tom, when I measurements both thermostats I did take the by pass valve into consideration and although I took the measurements cold I can't see the travel of the by pass being 2.5 mm less. Your do make a valid point and I could be wrong because I didn't take any hot measurements . But regardless if it's stamped 83c it should start to open at 85c at the latest and definitely not at 87c. I'm not done with this. I just don't have the time to devote to it right now.

Tom M'Guinn

For what it's worth, Stant's website says the thermostat should start to open within plus/minus 3C of the stated value, so if that holds for Wahler, you're just outside of the stated range -- though you have to wonder if the water was just getting hotter faster than the spring can open... If you ever get the change to test how far they both come out on the bypass end, please post. Would be good info to add to the collective braintrust. Something must be different between the two... Hope it works out now. Changing the t-stat is a special kind of fun

marc abrams

The water is definitely getting hotter than the thermostat was opening. At 195 degrees it was Open-barely. I doubt there was enough flow to cool down a *** .049. Anyhow those thermostats are gone now so I can't measure them hot. I would love to Know myself.
Which part, the snap ring or the antifreeze runing down your arm?