Oil Leaking from a 3.2 liter

[Tom Oxner]

I have an 85 3.2 liter with Motronic in my 72 911. I did the conversion over 15 years ago. It has been a really enjoyable car. The engine now has 85,000 miles on it. It has started to leak oil on the passenger side. I removed the heat exchanger to get a better view of the leak. The oil seems to be coming from the bottom mating surface between the head and the cylinder on the cylinder nearest the front of the car (the one next to the engine oil cooler). I checked the usual suspects of oil pressure sending unit and oil return tubes and they are dry. Any suggestions as to what is causing this oil leak? Thanks for your help.

Tom

[DRACO A5OG]

Cam Tower Lines???

[dentist90]

Leaks can frequently occur from the crankcase breather &/or oil thermostat on the top of the engine. The oil will typically trickle down the passenger side, often around the area of the oil cooler (which can also leak at it's o-rings). If you take off your air cleaner box you might be able to get a peak with a flashlight and a mirror to see if it's wet on top of the motor.
A leak from the top will only leave a few drops of oil on the ground after each drive, will not continue to leak if parked long term as oil is not getting up there if not running. A lower case leak will drip at a steady rate even when parked. Just a thought as I am preparing to drop my motor to get at just such a leak.

[rusnak]

If you have the stock exhaust, and the oil is hitting the cross pipe, I'd bet good money that it's either the oil pressure switch (not sending unit), thermostat o-ring, or crankcase breather gasket. If it's not the oil return tubes, about 80% of the time it's one of these (the big three). It could also be a cracked breather tube.

Dentist is right. Pull out the airbox, air flow meter, and then stick your head up and into the engine compartment, and get a good look directly down on to the motor to see if there is fresh oil. You can't see well enough to try to peek under the air flow meter with all the other stuff in the way.

If you see fresh oil there, we have a lot of tips to help you do the fix.

[JeremyD]

Your on engine oil cooler is right there in the front too - check the lines that go into that. The thermostat is one of the prime suspects - front of engine (near gearbox) - under the intake.

[JeremyD]

Your on engine oil cooler is right there in the front too - check the lines that go into that. The thermostat is one of the prime suspects - front of engine (near gearbox) - under the intake.

[old man neri]

I had my oil pressure switch go. It's a super cheap part. It's going to go sooner or later so you might as well replace it if you suspect it. On my 3.2 I was able to replace it in a few minutes with only having to take off the airbox but I have skinner arms.

[dentist90]

I would prefer to try to replace the thermostat O-ring and breather gasket with the engine in the car, but I have this recurring nightmare about dropping dirt, or worse a nut, into the openings.

[rusnak]

dropping the engine is a big job. I'd say for most people you are more safe to just clean the top of the engine with some alcohol and a bunch of clean rags. The most crucial part is to not drop any old o-ring fragments into the engine case, but you can't do much to lessen that risk other than to just go slowly.

One of the risks in dropping the engine is....well, you might actually drop the engine.

[Mr9146]

85K? Probably leaking from the cam towers...