IanS

I did a pressure test today right before the intercooler and I found a substantial leak.

It appears to be I, the temperature valve, according to Clarks Garage(http://www.clarks-garage.com/shop-manual/fuel-15.htm). It is directly in back of M (vacuum delay timed valve?) on that diagram.

When I disconnect the front of the two lines, I can easily block that line and nothing else seems to leak. When I connect that line, the plastic valve appears to leak, but I can't tell where. I checked the rubber connections coming in, and both appear to be in good shape. Is it possible the temp valve itself is leaking? Also, there appears to be a small, 3rd nipple on the valve which is leaking, but its hard to tell if its that or something else on the valve.

Thanks, Ian

IanS

Here are pictures I took from the passenger's side and the driver's side of the valve. I have no idea why it would be leaking, since I can't find any obvious holes. There is a bit of wiggle to the rear nipple, so maybe that is the issue.

Has anyone ever had a problem with this valve?

The first shows the two vacuum lines coming into the valve, and the second shows the valve itself sticking out of the metal coolant line below.

Theo951

Having a inside view of old type of this thermovalve 928 11 128 00 (from 951/ 86) you can see a minature hole among the two main pipes.
The new part 058 131 851 A which I have received from Porsche last year as replacement do not have this.
However keeping the old part the leak should be low & not an issue.
Ensure that the other black white ventil at test connector is not leaking throuth the metal valve to the intake of the MAF pipe.
Kr
Theo

IanS

Does that part just pop off, without me having to drain and bleed the coolant?

I think I'm getting a leak from the sides of that valve as well as the pinhole, because I couldn't stop it just by putting my finger on the pinhole.

Its enough of a leak that I can't hear any others when I'm trying to pressure test, so I'd like to replace it regardless.

Thanks, Ian

theedge

Its a screw in thing. Be careful with it, mine sheered off, making me replace that whole hard pipe. Not sure about the bleeding thing, maybe itll work out ok.

Theo951

IanS,
I was very lucky with mine, to remove it without drain coolant.
As theedge infromed you, work carefully without damaging the hard pipe.

IanS

Thanks, it'll be in my next order with Paragon.

-Ian

GPF

What does the valve actually do? The vac lines are disconnected from mine and I have not noticed anything untoward.....

Regards

Graham

'88 Turbo S

Theo951

Very briefly described,
it opens at coolant temperature of approx. 59 C and when the throtle is open even 1° or more ( vacum enviroment) its opens the black valve located at test connector.
Due to this & over the co-located & in series connected metal valve ( normaly is open but closes at high vacum) the MAF intake sucks all the vaporized gasoline from the tank system.
I see many setups were this function is deleted.
If you dontuse it, close the small hole under the throtle at intake.
Theo

IanS

FYI, I ordered this at Paragon today and the part number Theo gave me is a Febi part number at around $17. The real porsche part number rings up around $90, so definitely use the part number from Theo.

-Ian

GPF

Thanks Theo, that explains a few things for me!

So this is part of a fuel vapour purge system then.

Mine is a UK Turbo S and I don't think it has this system as I do not have the other parts on the inlet side of the engine bay that I have seen on other cars. I guess the valve I do have is just there to fill the hole in that water rail?

I will block off the vac connection under the throttle body as you suggest though. There was a vac line from there to that temp valve (via a tee with other vac lines) with the other port on the valve being blocked but the valve leaked. So when I fitted Laust's superb vacuum manifold (thanks Laust! ) I connected the line from the throttle body to it and blanked off both ports on the valve. I'll change that now I understand what the line was supposed to be for - i.e. nothing in my case!

Unless you know something else I don't?

Regards

Graham

Theo951

Yes,
It is better to block the hole at the botom of the throtle body.
Connecting it to Laust intake manifold you will raise your idle the same way as the screw of the throtle top makes.
Here is the system overview. The temp valve is in red.

IanS

I just replaced my valve, but after looking at your diagram, I think one of the largest problems is that I had the lines hooked up backwards before. Its possible that I wouldn't have had a vacuum leak if I had the valve hooked up correctly before. But the new valve seems like an improvement anyway, and the old one was a bit loose between the plastic and metal parts, so it seems like a worthwhile upgrade.

In the new valve, the two ports appear identical. Its a bit easier for me to connect them 'backwards' of what the diagram shows. Is there any reason that would be a problem?

-Ian

Theo951

It just oens at specific coolant temperature and there is no input of output on it.
You can connect it the way you like.
If oyu are so far make also sure that the black valve connect it this temperature valve is OK.
remove the vacum hose on the black valve ( comming from temp valve) and verify (use a vacum pump or blow inside) that is not leaking as well.
The metal valve is normal open.
Kr
Theo