89magic98

I replaced my oil pressure sending unit (928.606.203.01) with a new one from Vertex. The replacement did not come with a new crush washer.

The old crush washer did not come off the old sending unit cleanly. I tried to reuse it on my new sending unit. Unfortunately, I've got a small leak now.

I can't find the part number of this washer on my microfiche. Actually, I don't see a washer at all on the microfiche. Does anyone have a part number for the washer? Was it supposed to come with the sending unit?

I don't think I'd have much luck getting what I want at an auto parts store.

Thanks for your help!

ERAU-944

i need to replace this as well. also, i'd like to try replacing the one on my oprv. anyone have part numbers? or will i be to the local parts stores with the old ones trying to match them up...

-Mike-

89magic98

Bump.

pete944

PET doesn't show a crush washer for the sender. That's wierd, I know there is one.
The one for the OPRV is 043 815 3.

89magic98

OK, I found a replacement copper washer (for oil pan drain plugs) at Pep Boys (package of 2 for $2.79).

The washer that is the best fit is an M18 (see below). The fit is better than the picture indicates.

I will send another update when I get this installed, to confirm that this fixes the leak.

pete944

Let me know if that works. I think my sender is leaking, too.

Hans

The washer should seal, if not you might want to aply a little tod of teflon PASTE on the sender thread close too the washer.
Not too much: you dont want that junk in the sender or in the oil.
TakeCare

Zero10

Holy crap, throw that sending unit in a parts washer. Mine looks like new now =)

I used a copper washer as well. I couldn't find an aluminum one. Same on the little plug beside the sending unit.

89magic98

Oh, that's the old (broken) one. It probably got a fresh coat of oil on it with every oil change.

The new one looks much better. Thanks for sharing the info on the copper washer.

z3bra

Copper vs. Aluminum shouldn't be an issue, if anything I'd prefer the copper one as they tend to seal better since copper ones are a bit softer usually.

Zero10

Umm... * thinking* I think aluminum is softer, so I just tighten copper washers a little tighter (maybe 10% of reccomended torque values).
Worked fine for me.
I have to crawl under the car to check for a coolant leak, so I'll tell you guys if all my copper washers are leaking =)
So far oil level stays right on full.

Good to hear you're not re-installing that sender, lol.

I will take a picture of my sending unit while I'm down there =)

z3bra

Really it depends on the alloy, obviously something like 7075 isn't as soft as pure copper but copper alloyed with metals often has a hardening effect (Dunno why, I'm not a metalurgist). I believe the alloy used in the aluminum washers is 5716 which is about 30% copper anyway. To me it seems like I usually have to tighten the aluminum ones a little more but hey as long as it seals it's all good. Also copper has much better heat transfer than aluminum so if you're sealing something in an application that sees higher temperatures it will keep them closer in temperature to one another than an aluminum washer will. Different temps can cause varying expansion and potentially leaks.

Pure copper ones can be reused too if you anneal them, when you crush them it work hardens them. Heat them red with a blowtorch and then let them cool to the ambient temperature on their own. Just don't go crazy with a MAPP torch and melt em or anything. Softens them up nicely. Technically this works with aluminum ones too but copper is easier to gauge when it's the right temperature by looking.

You don't use copper on fuel contact seals since it will react wierd and and cause sludge to form. Also don't use aluminum washers to seal an aluminum flange, they tend to weld to one another and turn into a real pain in the *** down the road.

So in summary, copper washers on aluminum is the preferred type, aluminum washers on aluminum is bad, Copper washers on fuel system parts is bad. Take your chances with aluminum washers in that case even if it's on another aluminum surface. And lastly, copper washers are generally reusable many times unless the mating surface gets messed up provided you anneal them.

Oh and as for the original problem, I was asking about the seal on the sender when I picked up the other crush washers at one of my local Porsche mechanic's shops since nobody else in town had any. The guy at the shop said that the seal on the sender is part of the sender (sorta crimped on) so that's why there's no listing for it separately in PET. So the best choice if your sender seal gets bunged up is to just source a generic one that fits the diameter.

And on a related note, it seems that it's nearly impossible to get a 24mm crowfoot so you can actually torque that thing to spec, unless you want to buy one from Snap-On for big bucks. All well and good if it's something used regularly but that's a lot for something that won't see much use. I looked just about everywhere with no luck. The only ones I could find any cheaper were the ones that occasionally show up in the cheapo 10 dollar sets sold on Ebay. Had to resort to just torquing it down with an open end wrench and hoping that I got it tight enough to seal properly.

89magic98

OK, all this good information got me looking at the shop manual, so here's some more information to copy for use in this thread:

1. The exploded diagram in the shop manual shows the sender an washer as separate items. Maybe the sender you'd get from the dealer has the washer included. In my case, the washer was not included.

2. The sender thread is M18 x 1.5.

3. The recommended torque for the sender is 35 Nm (25 ft-lb).

4. It states that the seal should be replaced every time. "Install oil pressure sender with a new A 18 x 24 seal. Tightening torque: 35 Nm."

...

I could get a regular craftsman 24mm wrench into the opening to break the nut and do final tightening. Also, a Craftsman 6" adjustable wrench will clear the power steering pump without having to remove it like the Clark's Garage manual.

I've re-used the washer on the oil pan drain plug many, many times without a leak.

The original aluminum washer was extremely soft, and probably not reusable.

I will go and put that copper M18 washer in now, make another post on how it turned out.

z3bra

Mine was copper as well and I reused it without annealing it first, doesn't seem to be leaking yet. I also german torqued it since I didn't feel like springing for a 24mm crowfoot right now. If it becomes a problem maybe I will but I'm more worried about overtorquing it than tightening it down enough to make a good seal.

89magic98

I never heard of the phrase "german torqued". I bet I can guess though.

When it comes to tools I might use 1-2 times, harbor freight is not a bad choice - here's a 10 piece crowfoot metric set for $12.99:

http://www.harborfreight.com/cpi/cta...emnumber=47928

(Edit: these won't work because they are flare nut, not open ended.)

But I agree that you'd be screwed if you over-torqued it and stripped the threads.