Help me fix my oil leaks!

[Nathans_Dad]

Hello, I was hoping to get a little expert advice on the source of my oil leaks. To give a little background, I have owned my 1984 911 coupe for about two years now. When I bought it it leaked a little, usually the drips were from the low point on the case. Nothing big. About 8 months ago it started leaking a LOT more. This seemed to coincide with the oil change I did. I don't think it had much to do with the oil change though, it is leaking a whole lot more than that.

The leaks are pretty bad, I lose about 1 quart of oil a month. To try and identify the oil leak sources I spent today power washing the engine and using Purple Power degreaser. I was able to get a LOT of grime off but there is still a decent amount in some of the nooks and crannies. Hopefully it's clean enough to see the leak sources.

I think there are at least three spots leaking that I can see so far.

The first is the connection for this oil line. What is involved in fixing this? Do I need an entire new oil line?


The next one is one of the nuts on the drivers side lower valve cover is wet with oil. I assume this is just a gasket change. The wet nut is the second one from the left on the lower row.


The biggest one I think is coming from the oil cooler. I noticed when I started the car to dry the engine after cleaning it that there were drips of oil coming down onto the passenger side heat exchanger. Is this likely the gasket for the cooler? If so, is that an engine drop to fix?

Here is the front of the cooler


Here is the back of the cooler (I had to shoot blind with the iphone so forgive the photo quality)


And here is the heat exchanger on the passenger side:


I also noticed that one of the oil return tubes on the drivers side is markedly loose. I can wiggle it back and forth pretty easily. I assume this also needs to be replaced.

My current plan is to do all four return tubes, do valve cover gaskets, replace that oil line or fitting, replace any oil hoses that are easy to do and then whatever needs to be done to address the oil cooler. If I need to drop the engine I would rather just do it at the start and get the entire engine really clean and all the hoses replaced, etc.

Thanks in advance for any and all help, I know my post count is high but those are all off topic posts, lol. Now I am going to actually learn to work on my car!!

[mreid]

I recently went through this with my 86 930. I ended up dropping the engine for a complete reseal. This may be your best bet. Do it once and do it right.

[Smoove1010]

That oil line looks like a candidate for immediate replacement. You may want to attend to the "triangle of death" which is a dicey prospect without removing the intake, but at least you'd be short of a drop. Having just done a drop, however, I can say it's nothing to fear, and it will give you a chance to get to the pulley and flywheel seals, check your clutch, all the other "while you're in theres..." Good luck!
GK

[schumicat]

the 101 projects book has a great article on fixing common oil leaks. i replaced that oil line and you do need the line and it's pretty expensive ($80 or so). mine was leaking where the rubber/metal meet. the oil cooler seals are covered in 101 projects. can be done without engine drop but much easier with.

[James Brown]

you can take that hose to a hose shop that can crimp on a new sleeve on new hose, a lot cheaper

[Nathans_Dad]

What is that oil line called? It looks to me like it is the fitting on the flexible line that is leaking which I believe is the line that goes to the oil cooler up front. I am hoping my hard line is ok.

[wholio94112]

leak number 3 - potentially from the oil cooler - reminds me of the leak i went on to fix - hopefully - by getting compression tests done, only to find out 3 of my cylinders were leaking all of my secrets, which prompted me to remove everything on top of the long block to tackle the triangle of death - only to learn i was in denial that cylinder rings were broken and the engine had to be dropped and, etc...etc...etc...
...i am a former automotive/mechanical moron that has learn that there is a distant second thing i enjoy doing with my dream car....taking it apart to marvel at the functional engineering of the germans, and learning how it all makes sense...about a week away from being ready to piece it all back together, and as always with me and my hung-ho projects, i am sick of working and ready to drrrrive!!!
...but look deeply into that 3rd leak...it is a pain in the rump, and intimidation as all hell, but not that bad in reality, and not as hard as your mind can make it out to be!!!

[SchnellSchweitz]

To me, it looks like the oil is coming from above and not from the lower unit hose itself. Before removing the large hose for inspection, eliminate the chain guard housing, oil pressure sensor, small chain tensioner oil hoses at the front and near the top of your motor. Do a search for the "triangle of death" to find the common leak locations. You may find a very small puddle up top that is leaking all the way down. Those leaks travel.

[pete3799]

I would do an engine/tranny drop. Much easier to get to all the places you'll need to address
Have the oil cooler pressure tested while you have it out.

[Nathans_Dad]

Some good news! I decided to get a leak down test done before I drop the engine just to make sure the leaks were not related to any cylinder issues. I took the car over to Mayo Performance, which is only about 20 minutes from my house. They did the leakdown and it was between 4-7% for all cylinders! So, at least that's one less thing to worry about.

I have to say, the guys over at Mayo are great. I've had my car in there a couple times and every time it seems they do a great job and the cost is less than what I expected. I'm lucky to be so close to them. Plus, they always have some cool cars in there! Today there was a 1967 911 S which was getting a full motor rebuild. Serious cash there.

[RWebb]

congrats - I'd postpone the engine drop pending fixes to the other items above

also, clean the engine carefully so you can see the beginnings of the oil leaks before they spread much

the seals for the oil cooler will not last forever so will need to be replaced... someday

if the rubber oil hose is really old then maybe a new one is in order

[dshepp806]

Yeap,..that hose looks like it's getting it from "above" somewhere....how does that "triangle" look?

Sounds like you're on the right things to check (and sealed). A pressure check of that oil cooler will give you piece of mind.

Best!

Doyle

[Nathans_Dad]

I removed the air cleaner and mass air intake and took a look at the triangle with a mirror. It's dirty but really not terribly wet. Certainly not what I would have expected given the size of the leak. So, I am thinking it may not be anything back there.

Unfortunately there has not been any visible leakage since I did the cleaning/degreasing which makes me think the oil is accumulating somewhere before it starts dripping again. I just can't tell where! The oil breather hose was a tiny bit wet but I can't imagine that's the source.

Here is a pic of the triangle area, best I could do blind.

[Joe Bob]

DO a degrease and then run it....when clean it's easier to find the source of leaks.

[rusnak]

check your crankcase breather hoses, and also the air box drain hose. You can get some leakage due to blow-by. I would suspect the thermostat o-ring or oil pressure switch if the leak was dripping oil onto the exhaust pipe crossmember. Due to the fact that oil is leaking onto the pass side heat exchanger, I would suspect the oil cooler o-rings, which would most easily be replaced by dropping the motor.

[Nathans_Dad]

Originally Posted by Joe Bob

DO a degrease and then run it....when clean it's easier to find the source of leaks.

I degreased it yesterday, I can't get back there to degrease very easily. Wouldn't there be a risk of getting water into the intake since I have to pull the air cleaner and mass flow sensor to get back there to clean?

[Nathans_Dad]

Originally Posted by rusnak

check your crankcase breather hoses, and also the air box drain hose. You can get some leakage due to blow-by. I would suspect the thermostat o-ring or oil pressure switch if the leak was dripping oil onto the exhaust pipe crossmember. Due to the fact that oil is leaking onto the pass side heat exchanger, I would suspect the oil cooler o-rings, which would most easily be replaced by dropping the motor.

The more I look at it the more it seems it might be the oil cooler.

Either that or the oil return tube that is loose, I rotated it 180 degrees today to see if it would start leaking again.

It seems like it would be a pretty tough go on the driver's side to replace the tubes without dropping the exhaust??

[RWebb]

you could try carb cleaner

also, can you close off openings to the air cleaner & MAF with plastic?

[Nathans_Dad]

Originally Posted by RWebb

you could try carb cleaner

also, can you close off openings to the air cleaner & MAF with plastic?

Yeah, I could try that. Maybe I'll pick up some carb cleaner tomorrow and give it a shot after work. It would be nice to be able to see some actual metal back there, lol!

Part of me wants to drop the damn thing just for a good cleaning!! I don't think it's been out of the car in a while from the looks of things.

[rusnak]

you say this is a 3.2 911?

Remove the air box, the air flow meter, and unbolt the AC compressor if installed. You now have acres of room to work and stick a flashlight back there. I use aerosol electronic parts cleaner (kinder to plastic and rubber than other solvents), scraping, and paper towels to clean that area up with the engine in situ. If the oil return tube right above the leak is loose enough to rotate, then logically that is the area to focus on. Below the engine, you can use stronger solvents and higher water pressure. You might take it to a coin op car wash if your pressure washer is not strong enough.