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I recently purc a couple of repl thermo's (one 8v & one 16v) from a site sponsor. Both Wahler brand (better than Waxstat imho), ironically BOTH were too short (yes I'm sure). One also had a stamped manufacture date of 2000!
I'm assuming a deal was had on a very large quanty purchase, but damn...10 yr old rubber seals simply aren't going to provide good longevity. Regarding the "too short" comment, I'm refering to the distance between the large upper sealing plate to the bottom of the small lower plate. In this case, it was 4mm shorter than the distance needed to seal off the recirculation port in the cylinder head. I've seen this before...prob Volvo or Bmw applications.
Here's something I posted about two months ago (skip to the end if you're in a hurry). Btw, the only difference between 8 & 16v thermos that I can discern is an presence of a relief hole in the lower plate - as to which is which I don't know bc the part #'s on each box didn't match up w/the invoice (Doh!):
"Thermostat compatibility...8v/16v & a good tip too...."
I'm not so proud that I can't ask for help on mundane stuff.............so are Saab thermostats all the the same or not? I've collected a bag full in my 20+yrs of Saabing, from both 8v & 16v engines & they all look the same to me. There are some minor differences...some w/relief valves on top, some w/valves top & bottom, some w/none. Mostly Waxstat & Wahler (which definitely seems better made), w/a few lesser known brands.
I just boiled up all the units I had (that weren't obviously shot) & several tested within spec...all of these were Wahler, incl one made in WEST Germany. Most of the Waxstat units failed to close properly & all of them varied widely in opening/closing temperature (as did the lesser knowns). I'm strictly a Wahler man from now on.
For those of you looking for solutions to overheating issues, read on. I've removed a couple of thermostats here & there that were too short. Prob VW/Volvo/Bmw applications installed in error. Something worth investigating if proper cooling cannot be achieved. Parts counter guys (site sponsors included) are only human.
I'll share some knowledge I just learned troubleshooting a cooling malady on an old 8v'er (16v prob the same...or not?);
On the thermostat housing attached to the cyl head, the distance from the thermostat seating surface to the lower cavity port (where coolant is recirculated back to the head when cold) is 40mm. The distance measured from the actual thermostat seating "disc" (the big one) to the lower port "disc" (the small one) is 35mm...when COLD. If you have or buy a thermo that measures less than that...it's the wrong application & will not extend far enough to seal off the recirculation port when it heats up. In this situation, some percentage of the (hot) coolant flow will be diverted from the radiator & go right back into the engine. The "normal" (the average I noted while testing a batch of thermo's on the stove) thermostat opening distance is +- 5mm...which is JUST enough to span the distance referenced.
FYI
posted by 76.118.12...
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