Okay, this is how my Sunday went.

The weather outside was stormy - inside my garage my nice and warm thanks to my new propane heater. (Those things rock.) Changed the oil in my '91 90. Tightened down the valve cover as best I could (save gasket job for summer) to see if that would stop my oil leak. Thought I would install new switch for temp gauge and also crankcase breather. Well, a couple hours later I had replaced the breather hose. Of course I also had to jack car back up again, crawl underneath, and take splash guard off to retrieve dropped socket and hose clamp AND had to stop and put band-aid on finger from cutting through my fingernail trying to cut off old breather hose (sharp knife!)

Couple questions -
1. When I removed old breather hose (yuuuck) - I noticed gunky oil on both ends which I wiped out as best I could. What's this thing do again?

2. Multi-function switch. I took top radiator hose off to give me some more room. 20v repair site says to use an open end wrench. haha - yeah, right. What size? Biggest I have is a 1 inch SAE --IF I could even get at the switch. Should I remove air conditioner compressor? Or what's the thing bolted to the manifold just behind switch/hose? (Sorry for my ignorance here.) It's just a couple bolts - couldn't I just remove that? HELP!!!!

The thing behind the multi-function switch is probably the vacuum pump, there should be two 13mm nuts to take that off maybe alittle oil will leak out but not much. It is spring loaded and runs off a lobe on the cam. If it wants to push out turn the engine so it does not want to.

The multi-function switch, I used a 1 1/8" opened end which I had to "tap" on slightly to get to fit. Good thing those are brass, probably not the best way though. A big Cresent wrench, would work.

The breather hose is just an opening for pressures to equalize as long as it is not blocked totally it will work.

Jim Bush
Holland, MI

When you say "if it wants to push out..." are you saying I should watch out? My luck, (and good thing I asked), I'll turn the bolts out and springs and parts go aflyin'. What if I don't turn the engine over - won't be able to get it back on? I'm confused!!!!

There is a shaft in-between the cam and the vacuum pump. The vacuum pump has a spring (or something similar) to keep the shaft pressed against the cam as it is spining. When you loosen those nuts, if the pump feels as though it wants to pull away from the head by itself, that is the spring under tension. Just turn the engine by hand until there is no tension on the pump (less then half a turn). You can do it either way it is easier to remove that "pressure"

Nothing will come flying apart, well it shouldn't.

Jim Bush
Holland, MI

I've got 3 years experience w/ Honda/Chrysler and still can't think of what this "multi-function switch" is responsible for?

Audi follows their own rules...sorry for the dumb question

by DOT law you gotta burn crank air.

Multi-Function Temperature Sensor (F76)
The multi-function temperature sensor is located in the coolant flange on the cylinder head. This sensor has several functions:

When coolant temperature exceeds 119°C (245°F), the boost pressure is reduced.
Engine temperature guage.
Engine temperature warning light.
Climate control compressor clutch operation.