jwbeck17

Does anyone know where this goes to? I believe it was unplugged before I removed the expansion tank, but not 100% sure. Just want I make sure I didn't do any damage.

Schocki

Connector for pressure sensor....

jwbeck17

Great...now where's that? I was looking around the area and couldn't find it. It looks like this is the end that connects to the hood switch, but I don't know where the other end is. I have been unsuccessful in finding it in the manuals.

Bertrand Daoust

On one of the two lines on top of the expansion tank.

Bertrand Daoust

...

Schocki

The infamous pressure sensor...

jwbeck17

I guess it is so infamous that it doesn't exist on my car! I checked the two hoses, and one is solid all the way to the expansion tank. The other has two hoses connected together directly where the sensor would be. I guess it is not needed? Never had an issue before.

Thanks for the help! Merci and Danke!

Bertrand Daoust

Bienvenue Jason.

In the diagram, you can see a nipple (#42) near the switch (#8).
My car as a switch but no nipple.
I guess they put the switch there sometime between "87 and "91.
But there's nothing mentioned in the PET.

ammonman

Can you post any numbers from the connector? I've been trying to determine a part number without success.

The pressure switch was first installed in MY1984. The switch works in conjunction with the coolant level switch. If the coolant level of a cold engine is too low, the low level switch will send a signal to the dash after a 20 second post-start up delay to indicate low coolant level. As the engine warms the coolant expands. If the engine is stopped while warm and re-started the low coolant warning will not be triggered. If the low coolant level switch was activated, then on subsequent start the low cooling system pressure switch is activated the central warning system will store this sequence of events and maintain the low coolant warning even after the coolant has expanded due to heat and the low level switch is no longer triggered. In other words when starting the engine again the warning lamp comes on even though coolant level appears correct. If the coolant tank cap is opened (to add coolant for instance) the pressure is released and the pressure switch circuit opens. The Central Warning system interprets this as coolant has been added and turns the warning lamp off. It is intended to save on troubleshooting, but typical to much of the CTO (compulsive Teutonic over-engineering) it is often removed if it fails and not replaced.

Mike

Bertrand Daoust

So that's probably what someone did on Jason's car as it is an "89.

I also looked for the connector's part # but with no luck.
Curious too. Anybody?

Thanks for the explanation Mike.

Ed Scherer

I don't have a Porsche part number for the connector in question, but it looks like this viewed from the bottom on my '90 S4:



"9656"

Hmmm... actually, it might not have a separate Porsche part number, as it's probably just part of the harness:

soontobered84

CTO: I like that! It explains a lot!

Q:"What is that?" A:"Oh, that's part of the CTO"

the flyin' scotsman

Just looked on the GTS and the part is there.......I'll go get the super flashlight and extreme Parka and investigate......its cold but not going to stop me.

SeanR

As with most parts of our cars, they break with age. Mine was started to leak compromising the system pressure, leading to over heating. I pulled the connector and put a fitting in place of the sensor. All good.

the flyin' scotsman

The device is in line with the hose that's between the coolant reservoir and the top of the rad. per the pic Bertrand posted. The device on the GTS is again is as Bertrand pic with part # CTO928$$$




hope that helps as its -15c in the garage and Im not going back