Bad New Thermostat?
09-06-2020, 03:39 PM
#16
Rennlist Member
Thread Starter
George --
If you have drained the block via the two galley drain bolts, you may not see a lot of benefit from the extra flushes. If you don't remove those bolts, the block drains only to the level of the water pump inlet hole. The first time you pull those bolts is a little scary because the factory bolt torque spec is way too high. Put them back in with teflon thread sealing paste on the threads and the faces of the sealing washer, and try 16 lbs/ft torque when tightening them. Dave C (Worf928) started a thread highlighting the mistake in the factory number. A little searching will find that for you. It's a good read.
https://rennlist.com/forums/928-foru...-is-wrong.html
This one has some more background, including a recommendation for copper anti-seize. In my experience, copper is perfect for steel-in-steel fitups, but may be less than the perfect solution for the steel-in-alusil drain bolt situation. Meanwhile, because this is a wetted junction, the thread sealing compound keeps coolant out of the junction (threads), lubricates the junction, and also lubricates the faces of the washer, block and bolt to limit galling when tightening.
https://rennlist.com/forums/928-foru...ain-plugs.html
If you have drained the block via the two galley drain bolts, you may not see a lot of benefit from the extra flushes. If you don't remove those bolts, the block drains only to the level of the water pump inlet hole. The first time you pull those bolts is a little scary because the factory bolt torque spec is way too high. Put them back in with teflon thread sealing paste on the threads and the faces of the sealing washer, and try 16 lbs/ft torque when tightening them. Dave C (Worf928) started a thread highlighting the mistake in the factory number. A little searching will find that for you. It's a good read.
https://rennlist.com/forums/928-foru...-is-wrong.html
This one has some more background, including a recommendation for copper anti-seize. In my experience, copper is perfect for steel-in-steel fitups, but may be less than the perfect solution for the steel-in-alusil drain bolt situation. Meanwhile, because this is a wetted junction, the thread sealing compound keeps coolant out of the junction (threads), lubricates the junction, and also lubricates the faces of the washer, block and bolt to limit galling when tightening.
https://rennlist.com/forums/928-foru...ain-plugs.html
I only have one block drain on the drivers side, as the passenger side drain is JB Welded shut from exactly what you describe. The nipple broke off while overtorque-ing 10 years ago.
Not sure what the compatibility of G05 and Penafriost NF is, so I'm trying to get as much of the G05 out as possible
09-06-2020, 04:48 PM
#17
Chronic Tool Dropper
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Too bad about the broken boss, and I understand now why the extra effort on flushing is needed.
09-06-2020, 11:28 PM
#18
Rennlist Member
Vacuum filling is the ultimate solution. You need to seal the system of course, then fill from the bottom while pulling vacuum from the reservoir.
The 928 fills and burps pretty easily without a lot of fanfare with just the tiniest amount of care in preparation. There are other [not just] Porsche models that take a lot of effort to get burped and bled completely. Guessing that Pete has the vacuum fill system to support his 997. I use my home-brew version to fill my Honda Pilot DD cooling system, to make sure there's no air trapped in the top of the rear-seat heater cores. Lots of cars can benefit from this technique.
The 928 fills and burps pretty easily without a lot of fanfare with just the tiniest amount of care in preparation. There are other [not just] Porsche models that take a lot of effort to get burped and bled completely. Guessing that Pete has the vacuum fill system to support his 997. I use my home-brew version to fill my Honda Pilot DD cooling system, to make sure there's no air trapped in the top of the rear-seat heater cores. Lots of cars can benefit from this technique.
09-07-2020, 01:25 AM
#19
Chronic Tool Dropper
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Sounds so easy JIm. I have the venturi pump. I've been filling from a block fitting on the Honda. Sounds like a mr wizard fizziks experiment next time coolant is changed.
09-08-2020, 04:58 PM
#20
Rennlist Member
Thread Starter
Thanks again for all the assistance. After 3 full flushes, I think I got the old stuff out and filled with the new blue stuff. T-stat opened at about the right time and the test drive went well.
OAT was 83F and the needle sat a width below the 210 mark, which is what I usually see.
I had been having an idle issue as well. The engine was intermittently wanting to stall at stops unless I used the heel-and-toe method to keep some gas on it. I could then ease off the gas and it would settle.
I figured it was likely a vacuum leak, so I broke out my homemade smoke machine and found the leak at the left intake hose, the one that goes to the ISV/brake booster Y-fitting. A half a turn on the clamp took care of it. So I got that goin' for me... which is nice.
All this just in time for a road trip next week to WV for PCA Treffen at the Greenbrier, which includes a drive to the Back of the Dragon. Should be fun.
OAT was 83F and the needle sat a width below the 210 mark, which is what I usually see.
I had been having an idle issue as well. The engine was intermittently wanting to stall at stops unless I used the heel-and-toe method to keep some gas on it. I could then ease off the gas and it would settle.
I figured it was likely a vacuum leak, so I broke out my homemade smoke machine and found the leak at the left intake hose, the one that goes to the ISV/brake booster Y-fitting. A half a turn on the clamp took care of it. So I got that goin' for me... which is nice.
All this just in time for a road trip next week to WV for PCA Treffen at the Greenbrier, which includes a drive to the Back of the Dragon. Should be fun.
Last edited by GeorgeM; 09-08-2020 at 04:59 PM.