Attacking oil leaks...

[tirwin]

I’m getting back to attacking oil leaks. Thought I might poll the forum to get some thoughts on my plan of attack.

Good news is I previously addressed the triangle of death leaks and leaking crimped fitting from the left side oil line to thermostat.

Bad news is I have a new leak where the oil tensioner line goes through the right cam cover. Thinking I can’t get the engine tin out of the way without at least a partial drop. Thoughts?

Cam cover gaskets will need to be replaced. Opinions on dry or RTV? Seems like this is 50/50 split each way from what I can tell.

I inspected the underside of the engine and definitely have some wet oil in places. A while back I had cleaned it up so I could better determine what’s leaking.

Possible leaks at cylinders 5 & 6 cam towers. No broken head studs. Thoughts? Any chance of sealing?

Looks like old oil on and near the oil return tubes. Appears oil return tubes have been replaced with the ones that are prone to leak at some point in the past. I have a set of the good billet aluminum return tubes. Not sure the tubes are a problem but since I have the parts already why not replace and eliminate another possible leak source?

Looks like there is weeping at the valve cover gaskets (currently using the red silicon ones, but never again). Will be replacing the valve cover gaskets with the old school thick ones that John Walker recommends. Also will be checking the rocker arm seals for possible leaking.

Anything else I’m missing?

Thanks in advance.

[steely]

Dude I think you covered it.
Watch out for the tensioner/tower lines, there's like a dozen different PN's over the years. I didn't have to drop mine, but maybe yours is different.

[T77911S]

if you are talking about the seal that goes under the cover on the end of the cam, behind the tensioner, I just did mine on the 930. not sealant. there is also an Oring on that cover.

I think I lowered the tail of my engine. not a big deal, just the rear mounting bar bolts.
I don't think I took the rear tin all the way off. I probably cant do it because if the turbo, just don't remember without looking.

you may have done this, pressure wash the engine very well to verify oil leaks.
maybe your cam tower leaks are just rocker shaft leaks.

I use the orange(red) reusable valve cover gaskets without issue. I love them.
both surfaces need to be very clean and NO sealant. I thought mine was leaking, turned out to be the cam line where it attaches to the cam tower. very hard to see the leak. it ends up down on the bottom bolt of the valve cover.
use a thread chase on the studs and clean them up. the key is not to over tighten the nuts. if you see the gasket squeeze out then they are too tight. the nuts are barely snug on there.
hey, if you don't want them, send them to me. I will give them to my brother for Christmas!!

[tirwin]

Originally Posted by steely

Dude I think you covered it.
Watch out for the tensioner/tower lines, there's like a dozen different PN's over the years. I didn't have to drop mine, but maybe yours is different.

The leak appears to be the o-ring where the tensioner banjo bolt goes through the right cam cover. I thought the cam cover has to come off to replace it. Assumed the engine tin would prevent removing the cover. I would be happy to be wrong — that would make it a lot easier.

[tirwin]

Originally Posted by T77911S

if you are talking about the seal that goes under the cover on the end of the cam, behind the tensioner, I just did mine on the 930. not sealant. there is also an Oring on that cover.

I think I lowered the tail of my engine. not a big deal, just the rear mounting bar bolts.
I don't think I took the rear tin all the way off. I probably cant do it because if the turbo, just don't remember without looking.

you may have done this, pressure wash the engine very well to verify oil leaks.
maybe your cam tower leaks are just rocker shaft leaks.

I use the orange(red) reusable valve cover gaskets without issue. I love them.
both surfaces need to be very clean and NO sealant. I thought mine was leaking, turned out to be the cam line where it attaches to the cam tower. very hard to see the leak. it ends up down on the bottom bolt of the valve cover.
use a thread chase on the studs and clean them up. the key is not to over tighten the nuts. if you see the gasket squeeze out then they are too tight. the nuts are barely snug on there.
hey, if you don't want them, send them to me. I will give them to my brother for Christmas!!

Yep, that o-ring is leaking. Will go back dry with the new gaskets.

I’m hoping it is the rocker seals but I suspect it isn’t. Just a guess though.

Noted on the gaskets. Might not get done in time for Christmas though.

[tirwin]

Could leaking rocker shaft seals show up as oil near the exhaust ports?

[yelcab1]

These are typical oil leaks and all can be addressed without dropping the engine partially. You just need to remove enough to get there. The gasket and oring behind the tensioner housing is the most difficult as it means you have to retime the cam. The valve cover gasket goes on dry for an SC engine.

[tirwin]

Originally Posted by yelcab1

These are typical oil leaks and all can be addressed without dropping the engine partially. You just need to remove enough to get there. The gasket and oring behind the tensioner housing is the most difficult as it means you have to retime the cam. The valve cover gasket goes on dry for an SC engine.

Thanks.

Just to clarify that we’re talking the same thing... I’m not talking about the gasket behind the tensioner housing (although that could be another leak... hmmm). I’m talking about the o-ring where the banjo connects on the front side of the cam cover. That’s my leak source. Cam cover has to come off to install o-ring on inside of the cover — or so I’m told. So new cam cover gasket too. Valve cover gaskets are definitely going on dry. Question was whether the cam cover gaskets should be dry or not.

Question is to get the cam cover off seems to require removing the front engine tin piece (and maybe A/C bracket — can’t remember). I think removing the tin will require a partial drop of just the crossbar mounting bolts to get enough clearance.

[HaroldMHedge]

Replacing the oil line restrictor seals will not require pulling the front engine tin see the How To link below.

How-To: Replacing a 911 Cam Oil Line Adaptor
A Tutorial by Peter M. Zimmermann

[yelcab1]

I have removed the engine tin without a partial drop. Even if it needs a partial drop, it is not a big deal. In fact if I was faced with this, I would take the engine out. It is really not a big task for a 911SC.

[tirwin]

Originally Posted by HaroldMHedge

Replacing the oil line restrictor seals will not require pulling the front engine tin see the How To link below.

How-To: Replacing a 911 Cam Oil Line Adaptor
A Tutorial by Peter M. Zimmermann

Thanks but unless I’m missing something that is the other end.

Here is a picture. This is on the bottom of the timing chain housing cover, not the one at the upper valve cover. The oil is leaking around the banjo bolt. The aluminum washers on the banjo were already replaced. So the only thing left is the o-ring on the inside of the opening the banjo goes through.

[T77911S]

tim,
would look at the oil line to the cam housing first.
looks like that oil trail comes from up top. air flow can blow the oil around.
replace those 3(?) washers then clean it all off and check it again.
also look for "wet" rubber in those oil lines too. if wet they are leaking

been thru the oil leak thing. you gotta keep things very clean and check after short drives.

the one behind the chain housing was a questionable one for me. turned out it was leaking.

you know what REALLY sucked for me? I did all this, even replaced the 2 seals on the output shafts a few years ago because there was "trace" oil leaks. then once all was fixed the small seal for the shifter output on the tranny started leaking. had to pull engine for that one.

[T77911S]

BTW, just dropped my front cross member on my BMW to drop the oil pan to fix and oil leak.

[HaroldMHedge]

Tim,

Your correct, I thought you were talking about the other end.

You could replace the O-ring inside the timing chain cover but I'm not sure it would fix your problem. If you think about it the O-ring prevents oil from leaking between the cover and tensioner and if it were to leak it would be inside the timing chain cover.

To replace the O-ring you would have to remove the muffler and rear engine tin. 911 Carrera Chain Tensioner Installation covers this.

Before going that far I would replace the banjo bolt sealing rings again and check to make sure the line is not cracked, sealing surfaces are clean and good.

The factory installed supports on the later tensioner oil lines to prevent leaks from the lines. So are these installed?

[OsoMoore]

Originally Posted by tirwin

I’m getting back to attacking oil leaks. Thought I might poll the forum to get some thoughts on my plan of attack.

Good news is I previously addressed the triangle of death leaks and leaking crimped fitting from the left side oil line to thermostat.

Bad news is I have a new leak where the oil tensioner line goes through the right cam cover. Thinking I can’t get the engine tin out of the way without at least a partial drop. Thoughts?

Cam cover gaskets will need to be replaced. Opinions on dry or RTV? Seems like this is 50/50 split each way from what I can tell.

I inspected the underside of the engine and definitely have some wet oil in places. A while back I had cleaned it up so I could better determine what’s leaking.

Possible leaks at cylinders 5 & 6 cam towers. No broken head studs. Thoughts? Any chance of sealing?

Looks like old oil on and near the oil return tubes. Appears oil return tubes have been replaced with the ones that are prone to leak at some point in the past. I have a set of the good billet aluminum return tubes. Not sure the tubes are a problem but since I have the parts already why not replace and eliminate another possible leak source?

Looks like there is weeping at the valve cover gaskets (currently using the red silicon ones, but never again). Will be replacing the valve cover gaskets with the old school thick ones that John Walker recommends. Also will be checking the rocker arm seals for possible leaking.

Anything else I’m missing?

Thanks in advance.

My SC had a leak along the oil tensioner lines, where the flexible line crimped to the metal part. Quick and easy to replace with no engine drop.

My car also has the red rubber reusable valve cover gaskets. They work great and have at least 7 years of use and many removals with no issues. Make sure you properly torque the bolts on them: too tight or too loose and it leaks. Very easy to over-tighten.

[tirwin]

Made some progress...

Lower valve cover gaskets.
I'm not sure what happened to the left side lower gasket but it was totally destroyed (it was the red silicone kind). I don't believe I over-tightened it. I had the car at a shop to help me replace one of the thermostat oil lines. They did an oil change as part of the process. Maybe some well-meaning person tried to tighten. Pure speculation but the other one was fine so who knows? Another reason I'm not a fan of the silicon ones -- what happens when someone else works on your car and doesn’t know to use less torque?

Cleaned the mating surfaces again. Chased the threads on the studs. Used regular gaskets this time. Torqued to spec.

Rocker shaft seals
I took a close look at the rocker shaft seals. I didn't see any apparent signs of oil leaks there. There may have been a very slight leak on one but it was so slight I decided to leave well enough alone. If I have to do a top end then I will install the RSR seals.

Oil Sump Plate
5 out of 8 studs backed out with the nuts. Strange. 2 nylocks spun on the studs. Had to dremel the nuts off. Removed the rest of the studs. Chased the case threads. Cleaned the openings and blew it out dry with air. Locally sourced new studs with an allen head on the end. Applied blue loctite and re-installed.

I tossed the sump plate cover in the parts washer. When I pulled it out I realized that what I had always thought was a metal lip around the plate was actually a really old gasket! It was hard as a rock and tough to get off. After scraping it off I sanded the mating surface. At this point I realized that there were slight dimples at each hole. I suppose someone had just tried to tighten the nuts to stop the leaks and dented the openings. I used the ball of my ball peen hammer and a drift to flatten the dimples out. Then I did a final sanding, primed & painted the plate then re-assembled everything. I'm not sure if I fixed it or not -- time will tell. If not I'll have to buy a new plate.

"S" tube
Nothing was wrong with the S tube. It was replaced a couple of years ago. Old one was hard from age. I did, however, finally get around to installing the Rothsport check valve that I've had on the project shelf for a while, so that is done.

Oil return tubes
Not 100% sure if these are a culprit but I have 4 of the billet aluminum tubes made by Rauch & Spiegel sitting on the project shelf as insurance. Might as well install them now. I got 1 out of 4 done. My fine "made in China" circlip pliers snapped while trying to get the first circlip in place so that stopped progress. Tip broke right off. We were basically snowed in last weekend so I couldn't run to HF to buy a replacement.

Right bank of tubes is proving to be no problem. Not 100% sure I can replace the left side without removing the heat exchangers though.

Speaking of which, my heat exchangers are not in great shape. But that is mostly cosmetic as they still work fine. The part that worries me is the corrosion on the nuts. They are extra crispy and don't look like they are in good shape at all. I'm going to be holding my breath when the day comes that I do have to take them off. I fear broken exhaust studs are in my future.

Engine cleaning
I spent a bunch of time under the car with degreaser and rags. I'd say I'm about 60% done. Uwanna had a great suggestion. When I'm done cleaning everything up I'm going to dust everything with talcum powder before test driving. The idea is to make any leak sources more obvious.

To-Do List:
- Need to remove right timing chain cover and replace oil line o-ring
- Inspect tensioner oil lines for leaks
- Inspect top side of engine for any oil leaks that could be migrating below

Other Suspects List:
- crankshaft pulley leak (front of engine)
- cam tower to head
- timing chain housing to case

"Fixed" List:
- Crankcase breather vent
- idiot light switch
- oil cooler seals & casting defect
- internal thermostat
- flexible line between crossover hard oil line and thermostat
- rear main seal
- transmission shift linkage seal

[universeman]

Tim, good progress. If I could suggest a good pair of circlip pliers...they're invaluable when you need them. Don't get the HF - pay a little more to get a nice pair from AMZN ... regarding your sump plate stuff, be careful with that thing as the screen is NLA! Interested to hear how the Rothsport valve works out for you

[tirwin]

Originally Posted by universeman

Tim, good progress. If I could suggest a good pair of circlip pliers...they're invaluable when you need them. Don't get the HF - pay a little more to get a nice pair from AMZN ... regarding your sump plate stuff, be careful with that thing as the screen is NLA! Interested to hear how the Rothsport valve works out for you

My original intent was to get something quick to finish the job. But yea, I’m getting to the point where good tools is worth the investment.

These circlip pliers were Tekton brand from Amazon. So yea, maybe Santa will be leaving me something better under the tree.

My sump plate screen is the later style that is a separate piece. I just set it aside to work in the plate so no danger of messing it up.

[universeman]

I got the Channelock brand - they're awesome

[tirwin]

Originally Posted by universeman

I got the Channelock brand - they're awesome

Good to know! I was looking last night. The Knipex were $160+ for a set of four.