While the engine is out?

tevake · 04:26 AM

I currently have the engine and trans out of my S C to fix an oil leak.
It's been a few years since the last drop, but a slow leak onto the heat exchanger has driven me to try to fix it before I have a fire.

The source of the leak is the oil cooler. Once I got it off the seals look ok, but there is a lot of oil on the fin section of the cooler. So following suggestions from members here I immersed the cooler in water and pressurized it to around 10/15 lbs. just blocking the other port with my thumb.

No signs of bubbles. Does this seem like enough pressure to get a good check for leaks?
In looking closely at the oil pattern on the cooler there is some sign of possible blow by at the bottom seal. I'm wondering if it's likely that oil leaking from this seal would be able to migrate sideways and then up onto the fins of the cooler?
I hate to put it all back together with new seals and find that I missed the actual source of the leak.

Here is a look at the cooler, some smudging has happened from handling.
Ah, the pic is lower in this post.

At first I thought the oil had spread from the fin area around to the mounting face side
But after pressure testing the cooler it seems that the leak may be from that lower seal.
Any insight would be appreciated.

Also after the last engine drop, when the motor and trans mounts were replaced, there seemed to be a noticeable increase in engine vibrations getting into the cab.
Now in looking closely at the area just in front of the trans, there are signs of rubbing from the trans on the cross member . You can just see the shiny spots on the crossmember.

So I'm looking closely at the motor mounts to see how the engine and trans have moved forward to come in contact with this crossmember. And How do I get it to a position a little more aft to get clearance?

Here is the oil pattern on the cooler.

tevake · 12-04-2016, 04:23 AM

Dang each time I post a pic, then try to continue the text. It cuts off the last section of the pic details, then deleting the image. RATS!

At any rate, how to get the engine/trans to sit a little more rearward to get clearance at the front of the trans?

One other question, is it safe and a good idea to sandblast the engine fan and shroud?
I sanded and sprayed it clear last time and the clear coat has not done well.
So now, can I blast it clean? And what is a good way to keep it clean of corrosion and looking good long term?

Cheers Richard

tirwin · tirwin's Garage

Richard,

A few thoughts...

The top two openings in the oil cooler are the only ones under pressure. The bottom one is gravity fed only (no pressure). When I did this I found there were a few discussions about problems with certain replacement sealing rings. If memory serves, the green ones are bad and the reddish brown ones are the ones you want to get. I can't remember where I got them but it was a little tricky to find them. Maybe it's in one of the threads. I can try to look back through my invoices if you need me to.

Porsche issued a TSB on oil leaks by the oil cooler. This has been covered a few times and should come up in a search. If you look at where the oil cooler attaches to the engine case you will see a line where oil has leaked. You'll see a little dimple and that's the problem. Clean that area with a degreaser and then fill the dimple with JB Weld and you won't have a problem anymore. EDIT: I looked at your oil cooler pic again and that looks to be EXACTLY your problem. See where you have a big spot of grime near the big opening at the bottom. That is exactly where the dimple is that needs to be filled on the engine case side.

Check the triangle of death area on top of the engine. It's possible you have a leak at the oil pressure switch or maybe the hose came off the case vent and ran down that way. Or the seal around the case vent is leaking. Or the thermostat o-ring is leaking. All 3 are common culprits.

If you really want to clean up your fan, consider sending it to Mark Motshagen. Search for my thread "Mark Motshagen is a real craftsman" to see his work on my car and others.

jlex · jlex's Garage

There was a post a week or so ago about someone testing his oil cooler. Turns out, coolers experience a lot more heat/pressure than the 15lbs you're using to test. I might be wrong, but it sticks in my head that they were saying testing should be done to around 60lbs. As I recall, they sent it to a radiator shop for testing, but the consensus was even the radiator shop wasn't using enough pressure to test it properly. I believe it turned out to be a leaky main seal that was throwing oil that made it look like a bad oil cooler.
Maybe you can find that post...

fanaudical · fanaudical's Garage

The on-engine oil cooler sees full oil pressure all the time. I recommend testing right up to value of your oil pressure relief valve. However, this won't let you know anything about corrosion or possibility of near-failure.

For some peace of mind, I'd send it over to Pacific Oil Cooler Services. They will pressure test, inspect, and clean for a reasonable fee. Money well spent, in my opinion.

I do think that Tirwin is on to something in his post above.

Flat6pac · 12-04-2016, 09:32 AM

This is a cooler being tested using stompsky racing tester
Got to pressure 70 to 80#
Bruce

tevake · 04:13 PM

Thanks guys for the tips, details, and pic.
Looks like I should revisit the pressure testing, is 60/ 80 psi the consensus?

Not sure I want to look at the masterwork fans. What was the turn around time and cost? Isn't there an oil that soaks in and keeps the surface nice?

I'll take a close look for demples etc.

What are any thoughts about the front end of trans rubbing that crossmember ?
Is there any position adjustment in the motor/ trans mounts that I'm not seeing?

That pressure tester setup looks sweet.

All of the trio look clean dry and tight.

I probably will peak at those fans ��

Cheers Richard

tirwin · tirwin's Garage

Here's a pic of the leak at the case.

HaroldMHedge · HaroldMHedge's Garage

There is a TSB on sealing the case leak. A copy of the TSB is in this link.

911 SC Oil leak from notch above oil cooler on case.

tirwin · tirwin's Garage

I circled the spot with the 'notch' or 'dimple' to make it more clear. See how that spot lines up with the grime on the picture of the oil cooler? Clean above that spot and oily below it.

tirwin · tirwin's Garage

Corresponding spot here.

tevake · 12-06-2016, 03:01 AM

Thanks Tim, for bringing my attention to this probable leak point.
In looking closer that spot does seem to be where my leak is coming from.
Is that a flaw in the casting or what is that opening for?

At any rate, it doesn't seem hard to get it and the forward one also filled and sealed up.

Such a relief to locate a clear correctable issue like that. Makes me feel much more comfortable putting the engine back together and back into the car. With the expectation that the leak should be dealt with. MAHALO TIM.!

Now I'm thinking again about the contact at the front of the trans with the cross member just in front of the trans. Up to this point I've been focus on the motor and trans mounts, as they were changed just before this issue developed.

Any thoughts as to why the trans is not clearing this cross member and how to get some separation there?

Here is the demple under the cooler. And the wear points on that cross member in front of the trans.

Cheers Richard

Flat6pac · 12-06-2016, 03:47 AM

I would think the trans moving off location would correspond with weak motor mounts.
Bruce

tirwin · tirwin's Garage

Yes it was a problem with the casting.

I've been thinking about the rubbing. There is a little play with the motor and trans mounts but I'm not sure it would account for that. Is there any chance the crossmember on the front of the engine is slightly bent? If it was, I suppose that would cause the motor and trans to sit further forward. I'm not sure how the trans mounts would line up though. Maybe when you put the engine back in you can find someone to help be a spotter to see if you can align it a little further back.

tevake · 07:05 AM

This contact between the trans and the crossmember started right after replacing the mounts. The mounts seem simetrical so I don't see them being in backwards. I'll pull them off to see if there is any other way to bolt them in, that would affect the position of the engine.
I'm going to have a close look at the crossmember and it connections to the tub, to see if there are any signs of movement there. The clearance does not have to be big, just enough to keep them apart.

I took the oil cooler to a radiator shop that has done some good work for me. They said they would have to fab a plate to be able to test to the 75 psi . This will probably cost close to the test piece shown here earlier. So I may look into finding one of those test pieces for myself.

Cheers Richaed

tevake · 12-06-2016, 07:09 AM

I'm working in my nomad garage, so have to wait for warm enough temps to get into it.
Cheers Richard

tevake · 03:41 PM

Had some nice weather today, and did some cleaning and looking around.
In the service notice Porsche mentioned sealing the casting demple that is inside the space that the cooler fits into. I'm wondering if it's a good idea to also fill the corresponding demple on the aft side of the cooler.

Also, while in there Im looking at doing a heater back date. The blower and most hoses were removed before the car came to me. This was fine in Hawaii. But now some heat seems like a good thing.

I've found that our host does offer the right side shroud outlet port, but I haven't found a pass thru piece for the tins to get to the heat exchanger. Any leads for that piece?

This is a plugged piece that is in place.

I made a troubling discovery while cleaning the built up oil on that side of the engine.
Found evidence of an old crack in the case that has been touched in the past.

I've not seen leaking there, but then I hadn't noticed this crack before either.
What should be done about this crack? Put back in the car and watch it.
Find someone that can weld it, would the engine have to be completely disassembled to do welding in that spot?

Thanks for any input.

Cheers Richard

pmax · pmax's Garage

^^^
Looks like it's cracked in two places (?)

Is there any other visible damage to the case ?

Flat6pac · 12-09-2016, 11:48 AM

I believe it casting flaws.
Bruce

75 911s · 75 911s's Garage

Wow! That crack is heinous. Curious to see if something like that can be repaired. I think if it were mine,(and being that I'm on a certain budget) I'd put it back in and drive and see if it leaks or any other major issues appear. Then I'd start looking for a new case for a future replacement.

As for the block off plate for the heat back date, can you remove that plate, I see a gap at the bottom. Sand it down and have the tin powder coated satin black. If the plate is part of the whole piece, place a WTB ad in the classifieds. Tons of engine tin out there.