Hambisa

Over the past week I found oil dripping from the right cam cover below the pressure sender unit, which was very wet around the base. Then the OBC began flashing "sensor failure" messages, along with momentary heart-stopping 0 psi readings on the oil pressure gauge.
I searched this forum and found several references to similar situations, usually concluding with the dealer or indie replacing the unit. I purchased a sender from my indie ($55) and set about replacing it myself, as I wanted it done before the weekend. Here is what transpired:
1. The oil sender unit is located forward on the right side of the engine. In the first photo you can just see it behind the A/C hoses. The second photo is a closer view.

2. The base of the sender unit has a 19mm hex, and it was immediately apparent that a standard combination wrench of that size would never work in the space available (with the engine in place.) Thinking a crowsfoot wrench might be the answer, I headed to the local tool store. (For those in this area, Pat's Tools on El Cajon Blvd in El Cajon, CA, is a great resource for new and used tools of every kind.) The shank of a crowsfoot doesn't clear the base of the sender unit, so the counterman in the store went digging through boxes and bins for something that might work. He showed me the tool in photo #3, which I thought had definite possibilities, if I opened the end to the black mark so it would slip onto the hex from the side. It is 3/4", same as 19mm, and the 12-point fitting would facilitate working in a narrow confinement. They charged me $3 for the tool.

3. Back home, a few minutes of Dremel magic and a file to smooth the edges, I had a compact open-ended wrench that slipped onto the sender's hex. Photos 4 & 5.

4. I pulled the wires from the sender unit and, working by feel alone, with the tail of the wrench in the space towards the rear of the engine, easily (perhaps too easily) loosened the old sender and unscrewed it by hand. Replacing it with the new unit (which comes with a new sealing washer fitted,) I was able to get enough leverage for a secure mounting. I re-attached the wires - note: one wide and one narrow terminal, and cleaned off the dirt and oil around the base with a rag. Photo #6.

5. Ignition on, started the motor: normal readings on the oil pressure gauge, and a flashlight in the engine compartment to check that no oil was spraying around; so far, so good! My forearm wasn't entirely unscathed, however, as those tight confines have several hose clamps and other painful protrusions.

6. Like most enthusiast Porsche owners, I have been blessed with the necessary OCD, so, removing the right rear wheel, I proceeded to take off the coil shield and clean away as much of the accumulated oily crud from the cam covers and surrounding area as I could. It seems that the sender unit had been seeping for a while before the dripping made it apparent. After putting it all back together and doing a couple of hundred miles this weekend with no OBC messages, the bottom of the motor is bone dry!

I hope this DIY proves helpful to someone who, now or in the future, may need to replace the oil sender unit -- it doesn't require a Porsche shop or $400 P-tool to do the job. If a regular Rennlister needs it, I'll be happy to loan them my "priceless" tool. PM me.

P.S. Southern California + Early Summer + 911 Cab = HEAVEN!

DCP

Man, thank you for this. I needed it!

Very clever with the tool mod.

ivangene

+1 for tool tip !

function12

What about one on these?

Sears 19 MM Extreme Ratcheting Wrench

007DT

So how long did it take you... Just had it done on my car and the shop charged me 1.5 hours?

Hambisa

Once I had the tool modified, and not counting cleaning up the accumulated muck underneath, swapping the sender units took no more than ten minutes. Nothing else has to be removed to access it (except some skin if you don't avoid those hose clamps!) 1.5 hours seems rather "generous."

007DT

Strike 2 on these guys!

wross996tt

Ian, nice job. I'm sure this will help others save some $$$$.

deckman

I am trying to do this job right now. It's super tight down in there and the wrench I am working with is cut down to about 5 or 6". Unlike the OP, the sensor on my car is in on very securely. I can't seem to get enough leverage to loosen it. I'm tempted to take pliers to the top of the unit and try to get it loose but am afraid I'll just crush it. Then it would still be stuck and I wouldn't be able to drive the car.

Any ideas?

lotecredneck

Remove the right rear wheel and then remove the heat shield. You will then have a little better access to the sender where you can place the wrench on the hex part of the sender and use both hands or tap the wrench with a hammer to loosen the sender.

Tony

fpb111

They have been using that design sender since at 1969. I wonder if it is the same part # ? Probably not the old ones were single wire.

deckman

I did finally get the unit loose using a wrecking bar wedged against it and using my body weight against it. However....

This is getting comical. I rigged a wrench like the OP did, basically cutting open a box wrench and shortening it so it would fit in the confines. I'd take a pic to show you but....it is now stuck on the bolt attached to the underside of the sending unit. It wiggles up and down and left to right, but I can't pull it off to save my life. I don't really know what to do about it.

I tightened the unit back up and went to get new tires today. I am driving with a wrench in my engine bay. But believe me it isn't going to fall out.

Dharn55

OK folks here is the tools that makes this simple. A 19mm Crowfoot wrench. Use this with a 3/8" universal, extension and socket wrench and the removal is simple.

Jack up the car, put in a jackstand, remove rear right wheel, slide the crows foot wrench in from the bottom, you need the universal to get the wrench on due to the angles around the spark plug shield. A little twist on the socket wrench and it loosens right up. the just spin it out from the top, spin the new one on and tighten it down with the crowfoot. Really easy and fast.

Got the crowfoot at NAPA, here is a link

http://www.napaonline.com/NOLPPSE/(S...cf19m&Ntk=Part Number&N=0&Nty=1&D=ncf19m&Dn=0&Dk=1&Dp=3

Probably available from other sources. Made the job incredibly easy.

Schützenweber

Last night it happened to me ..

The OBC signaled an 'Oil Failure' message and my heart also stopped upon seeing the Oil Pressure Gauge dive from ~5 bar to zero while speeding down the freeway!

The Horror, the horror ...

I knew something was screwy as the needle intermittently bounced back and forth from zero to 5 bar; temp was normal and I check the oil ritualistically.

The Gauge started operating normally again at lower speeds and I didn't stop.

Good thing for the search engine here. I do hope it's the sending unit.

Time to see the dealer for some CPO warranty work!

Thanks for the valuable info.

deckman

When you take it to the dealer it won't show any codes when the check and they won't be able to repeat it so their normal reaction will be they can't find anything wrong. I did this twice while the car was under CPO. Tell them exactly what happened and tell them you know from research it is the oil pressure sensor part # 996 606 203 02 that needs replacing.