Oil Leak Diagnosis (with pics)

[shrouded]

So, I am finally going to tackle my oil leaks. I would love to have things sorted well enough to participate in a PCA or SCCA autocross at the end of the month... anyone know how strict they are about passing tech inspection with drips?

Anyway, this is what I observed under my very grimy car. Do my plans make sense?

This one is easy. I'm guessing a new S-hose is in my future.



Oil return tube, passenger side. I probably need to do the others as well, but they don't seem to be contributing to my current drips so they may wait a little while.



Valve cover, passenger side. There is a slight amount of wet oil (as opposed to dried grime) at the base of the valve cover. This could be contributing to the smoke I get when oil burns off of the SSI, but the oil here is minimal and could be coming from the oil return tube shown above (I think). The valve cover is going on the project list, but probably won't be done in the next couple of weeks. By the way... this is a standard (i.e. non-turbo) cover, correct?



Finally, the most problematic of the leaks. This one appears to be dropping the biggest volume. I can't see the source, but I traced it dripping from all over the bottom area (see the last picture) up through the area shown below, before disappearing. My original PPI showed an O-ring at the thermostat that hasn't been taken care of yet; is that a likely cause for what I am observing here?

[kach22i]

Originally posted by shrouded
By the way... this is a standard (i.e. non-turbo) cover, correct?

I think its a turbo cover.

Nice pictures, no flash - I don't see any hot/washed out spots.


Covers:
http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_911REC_pg13.htm

[ianc]

Regarding #1,

I think it is not the S hose that connects to the hard line under the cooler, but the one behind it. Mine leaked (oozed) out of the joint and I had to replace it too. It was kind of a bear since I believe it connects to the t'stat...

ianc

[smcdermaid]

Agree with Ianc, Pic one is probably the fitting for the line from the thermostat dripping down onto the S hose. I just finished this replacement myself.

[shrouded]

Thanks for the replies... both here & via PM. I'm making a list of what I need to order from Wayne.

It looks like the oil return line is a no-brainer.
Add to my shopping list

• 2 x OEM Expandable Oil Return Tube Kit, includes seals (seems good to have a spare)
• 2 x Circlip for OEM Expandable Oil Return Tubes Only (again, I like spares)

It sounds like I should go ahead and take care of the oil pressure sender. I think all I need is the part below. How likely am I to be able to do this without dropping the engine?

• Oil Pressure Switch, 911 & Turbo (1974-89) C-606-230-00

I suppose I should go ahead and get a couple of the thermostat o-rings now, although I will likely put this off if I can take care of the oil pressure switch without starting my first engine drop. Unless, of course, it is possible to replace the o-ring without dropping.

• Internal Thermostat O-Ring, 911/911 Turbo (1974-89)

Am I forgetting anything? What are my odds of getting through this without an engine drop?

[DW SD]

for installing the expandable return tube, check the archives. They are a ***** to install unless you use the correct silicon based lubricant. I thought motor oil would be fine. I used syl-glide. You'll need some hose clamps which you can use to clamp and pry against. I did mine with the Heat Exchangers out and they were still a good fight.
John Walker's tips were excellent! You shouldn't need an engine drop for any of this, I wouldn't think. I'd clean everything up with very hot tap water and laundry detergent or simple green. Might as well do it before so it is not so messy when you take everything apart.


Doug

[MBAtarga]

With an SC (CIS), you'll need to do at least a partial drop to replace the oil pressure switch and the internal thermostat o-ring. BTDT - I did a partial, and had to keep removing more stuff to get room to replace these parts, and then decided to clean up the area while I was there.

[copper]

The all-over oil spread on the underside looks much like mine did. Although I had leaks in the lower valve covers (original, now replaced with turbo covers), surprisingly, the majority of the underside oil was coming from the topside and running down. Due to the shroud, I wasn't able to see how much oil was actually leaking from the crankcase breather, oil thermostat and pressure sender. It was running under the shroud and engine tin and onto the top of the case, then down through all the pathways it could find.

A good way to tell without a drop, is to remove your fan and housing (with the alt) and look at the topside. You'll see if it is smeared with sludge like mine was. This is fairly common, and a good indicator of the origin of the leaks.

Being viscuous, oil will adhere, and flow along surfaces, so just because it coats a hose, doesn't mean the hose is leaking. It may be running down there or being pushed by air/gravity.

Try a bottle of flourescent, then black light it. You'll be able to see where it's originating from.

Here's a picture of the gunk on top of my engine. And this is after cleaning much of it. I'll try to find another and post it.


If your fan blades are fairly dirty, it can be a good indicator of an oil leak on the other side.

Jim

[copper]

Here's a pic of another members engine with the same source of leaks.



And here's the thread.
Oil on the top of the engine

Jim

[autobonrun]

In addition to the breather hose mentioned by Copper, check the overhead cam tower lines on both sides. Oil from them will make its way down to the bottom of engine. I just finished replacing mine. The one on the passenger side leaked badly and ended up smoking on my exchangers. That fix along with the valve covers cleared up the majority of my leaks.

[shrouded]

I need to go check the 101 Projects book again, but in the meantime... exactly how partial is a partial drop? As with every time I wrench on the car in a new way, I'm a bit nervous about the process.

[safe]

A partial drop is when you loosen the rear engine mount and drop the rear of the engine.
Just disconnect your shift coupler (if thats the word for it) under the hatch in the center tunnel first so you don't bend anything.
You will probably be able to lower the engine 4-6 inches (if not more) in the back.
Watch out for wires and hoses and the shift rod from the gearbox when lowering. You can probably loosen the transmission mount a few turns to relive some stress from the rubber mount.
I have not done this myself, I did a complete drop this winter to get on top of my oil leaks. My engine looked like the pictures above.
Unfortunately my engine still leaks on the passenger side heat exchanger, but the top of the engine is clean.

[randywebb]

you have the turbo covers already

it will be easier to figure out where oil is coming from after you steam clean or pressure wash the engine (use hot water if possible) use the orange oil type cleaners too. Then repost some pics after driving for a while.

squeeze the S hose at every spot and see if it is soft anywhere - if so, replace; if not it is probably ok