Thaddeus

There's a round rubber doughnut gasket at the back of the thermostat housing that the thermostat plunger rests against at some point in the thermal cycle. Mine was all chewed up. I ordered the part from 928intl, and am wondering about how to secure it. Is it a press-fit part? or is there some special Porsche adhesive made from Black Forest Unicorn sh*t that I need for this?

Thanks in advance.

Thaddeus

Kevin in Atlanta

Press fit. Find a socket and use it to tap it into place.

Thaddeus

Thanks

Garth S

" is there some special Porsche adhesive made from Black Forest Unicorn sh*t that I need for this?"
Yes and No: Yes, there is a special adhesive as you describe, but no - this is not the correct application!
86_5 is correct re. a press fit. The ''barrel' of the gasket that inserts is ribbed such that it inserts easily - and is difficult to remove.
If you haven't yet removed it, don't waste time trying to carve it out ( you have one guess as to how I know). The insert is moulded over a mild steel ring: to remove, drive the edge towards the center with a (factory approved) screwdriver. It collapses quite easily.

Thaddeus

Well, the new thermostat is in. While removing the old gasket ring at the back of the thermostat housing, I had one of those "O lord what have I done" moments..

I was collapsing the ring as in the post above, and it came free. Then I heard a "kerplunk!" sound and it was nowhere to be seen. It had fallen down the coolant passageway into the front of the block... stuck my fingers down there, nowhere within reach. I was thinking: "How long will it take that thing to work its way to the impeller, destroy the water pump, and break the timing belt if I leave it in there? How much of this engine will I have to take apart now? Arrrrrrrrrrgh!"

HOWEVER I lucked out big time! I bent a wire coat hanger and went a-fishing. I snagged it on the first try!

Rufus Sanders

thadd,

Dude, you are doing the trial by fire, but good! Keep at it man. You'll be SO proud of all the work when you're done. - Ruf

John Struthers

So...
I posted a question about this several weeks ago and though
I recieved two replies neither of them physially showed when I clicked
on the post threads ???
Anyhow, when I went to install the new thermostat from 928 INTL there was NO aft end extention - well it's shorter- that fits into the recess that you described.
What I was wondering was: If the thermostat was a different heat range than the original - I forget now if I ordered the 75deg C, or 83 deg C
thermostat - is the body of a different design?
Seems to me that the thermostat has a function to serve by being
located in the aft recess, not to mention that the thermostat would
appear to be stabilized with the tail end being in the recess.
For visual reference if you have Vol. 13 -2004, page 18, bottom right is
the one I just installed. It is much shorter than the original and the aft
end disk is smaller in diameter. While it did come with the large O ring it did not come with the paper(?) gasket that was originally placed between the Gooseneck face and housing. So I made one.
After installation I lost about $40.00 of DexCool due to two events well after cooldown -unwitnessed- there was no pressure on the system and the tank cap was removed to check level then re-installed. I used a rubber plug with a small hole in it, an inflator spike (football/basketball) and a tire pump. Could not force a leak anywhere. Looked everywhere after the leak downs, no fluid in the 'valley', around the heads, tank, radiator, coolers, hoses ... . I did find a dried fluid trail beneath the coolant tank but no start point.
I filled the system a third time and level has remained stabile,no leaks,
and temp gauge climbs to just under mid-point and stays ther irregardless of temperature, duration of trip, or engine/road speed.
I'm at a loss for a reason for the earlier overflow/coolant loss.
Any ideas to fluid loss, paper gasket, thermostat shapes?

Garth S

Thadd,
Good catch! You must have used a regular screwdriver - the 'factory approved' ones are magnetized to prevent such incidents.
John,
I flashed back to your post, and there are 4 responses sitting there. The 83 C pellet is the only one to use IMHO: If supplied by any of the Big #, it's 99.9% correct: well, nobody's perfect.
The disc/flange on the tail end extends when hot to seal against the opening in the block: it does not fit into that opening. When 'opened' by warm coolant, the rear disc 'seals' that opening to redirect flow to the rad, a reverse engineering to almost everyone.
If on installation, the thermostat was placed in first, with the disc leading the way - then the O-ring laid on top, everything is correct. The O-ring must be on top to allow the disc to extend far enough to seal correctly when opened. No paper gasket is either supplied or required - the O-ring is the seal for the housing .

maddox

Thaddeus - I took the housing off to do this job due to leaks at the base of the housing. However I used a silicon grease on the seals etc. that was sticky as hell - In your case this may have stopped it from dropping inside .

sstrickstein

I am doing this same job right now. I installed a prestone flush system today. I decided to replace the stat with a cooler one at the same time. Once I got the old stat out the rear seal was missing. My cars symptoms are running up near the 2/3 mark while in traffic or sitting idling for 5 or more minutes without moving. Can that seal being missing cause this? I tried to use a socket to install and could not get it to go. Wondered if I had the right seal. It looked correct. I will give it a try again this weekend. Any suggestions on this would be appreciated.

Tom. M

Sometimes it looks like the seal is missing but in fact it's just corroded in place and looks like part of the block... Make sure it's gone... The new seal should just push in with a little force..

sstrickstein

I did check. I could see the recess in the lip where the seal would sit. There was no corrosion on the housing at all. I just read the factory manuals and there was no mension of this seal. What can happen If its not there? Will enough coolant flow be altered so that the car will overheat? I am going to try to find a correct seal press but my fingers are scared and raw from trying tonight to press this thing in.

Tom. M

If the seal at the back isn't there, I think some coolant would get diverted to the rad, but it would likely still probably not be as efficient as if there were a good seal. So chances are that is what is happening on yours. The thermostat expands as it heats and blocks that hole so the coolant flow will be through the rad. Yours sounds like it was "leaky"..so you probably had coolant cycling in the block with some going through the rad.

I had the opposite problem. my thermostat was "stuck" on that seal so all my coolant was always running through the rad....and car never warmed up when driving....

Mike Frye

SStricktein,
I think you need to rethink the cure for this issue. The temp of the t-state indicates how soon the water starts circulating through the full system. Once it's up to full temp the t-stat isn't going to make anything run cooler.

I think you have a fan/circulation/radiator problem, not a t-stat problem, but that's just me.

Tom. M

The T-stat is part of the circulation problem...if some of the coolant is being returned to the engine (since it's not sealing at the back seal)...it will run hotter when sitting since he's not getting the full "flow" through the rad.. If he replaces the seal ....and still has the same problem..then yes...look at the fans and rad...

2/3rds' on the gauge isn't that bad..as long as it doesn't go overtemp...you'll be ok..