Hai gebissen

I got a new hose because the PO cut the old one at the nipple on top of the radiator. I installed it and...it is an inch or two short of reaching the expansion tank. In this area, there is a two wire terminal housing plugged into nothing, with nothing around to plug it into. The wires are blue/red and brown.

My brother (Courtshark) has this same two pin terminal plugged into something in line with this hose on his '88. Can someone please tell me what this thing is, and do I need one? For now I will have to use a section of my old hose and a junction to lengthen it to reach the expansion tank.

Sorry I don't have a picture, but my brother has one of his if he'd be so kind as to post it here.

Thanks in advance.

dr bob

It's a pressure switch, used in conjunction with the coolant level switch in the reservoir top to alert you when there should be higher coolant level in the reservoir. They are fragile and often get damaged accidentally when working in that area. A few years ago they were getting onto the NLA list every once in awhile. Many people decide to just leave them out. A short piece of 8mm or 5/16" hose is all you need. I used high-press fuel hose to replace both of those vent hoses completely, been good for about 6 or 7 years now. The factory hose wasn't on the shelf at my local supplier at the time.

westija

There are two sensors : one for coolant level and one for pressure in my car. You might be missing one of them.

Check this site for additional info:
http://jenniskens.livedsl.nl/Technic...1/MyTip125.htm

On an old post from Wally: "Each sensor has a blue/red wire and a brown wire. The brown wires are simple chassis grounds. The blue/red wires are joined together at terminal M11 at the Central Electrical Panel, so the blue/red wires should read the same thing at each sensor.
Wally Plumley
928 Specialists"

And another there:
"From the "service information model 84" document:

"The central warning system has a pressure switch located in the return line to the expansion tank which works in conjunction with the coolant level switch. If the coolant level of a cold engine is too low, this will switch on the coolant level warning light after a delay of approximately 20 seconds. Coolant will expand as the engine warms up and the coolant level will rise. If the engine is stopped and started again, the warning will go out. This happens even though the cold coolant level is too low. To avoid unnecessary troubleshooting, the pressure switch senses the pressure in the cooling system and sends this information to the central warning unit. Now if there had first been a warning from the coolant level switch and afterwards from the pressure switch, the central warning system will store this signal sequence and maintain the warning, even after the coolant has expanded and the coolant level switch has an opened circuit. In other words, when starting the engine again the warning lamp comes on, even if the coolant level appears correct. If the cap at the expansion tank is removed (to add coolant), pressure escapes and the pressure switch circuit opens. The central warning system, with this indication, assumes coolant has been added and turns the warning lamp out."

Hai gebissen

Wow. Gotta love German cars.


Thanks guys.

Hai gebissen

Anybody have a part number for this pressure sensor?

Tom in Austin

Gee, I always thought the pressure switch was to indicate a failing head gasket pressurizing the cooling system.

Figures those guys had a much more involved solution in mind ...