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1991 420SEL, 1989 Porsche 928-S4, 1973 Lincoln Continental Town Car, 1960 Lincoln Continental Mark V
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Discussion Starter #1
I replaced my valve cover gaskets last weekend because, after smelling burning oil more than once inside the car when idling, I noticed oil drip lines in a couple of places to the headers. Replacing the VC gaskets wasn't too much of a pain, but got it done in about 90 minutes.

Idled the car, and didn't see any oil around the VC.

After driving the car about 10 miles the next day, however, I noticed I was being followed by a HUGE cloud of blue/gray smoke. When I stopped, blue/gray smoke came out from under the hood, grill, and upon inspection, the entire underside of the car was bathed in oil.

I rechecked the VC gaskets, and no apparent leaks there. I double checked under the air cleaner - no obvious oil. There is obvious oil loss on the oil dip stick (no big surprise, since it's obviously on the undercarriage or burned off).

What could I have possible done while changing the valve cover gaskets to cause this kind of leak? Is there some kind of oil tube I might have pulled in removing a VC (particularly the drivers side, since that on is really sandwiched in)?

Help? :confused:
 

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Depends on the day!
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13,337 Posts
it's pinched somewhere..take it back off and re-seat..

Jonathan
 

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1991 420SEL, 1989 Porsche 928-S4, 1973 Lincoln Continental Town Car, 1960 Lincoln Continental Mark V
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Discussion Starter #3
But, if it was pinched, I'd see a leak around the VC at the pinch, right? I'll check again, but I from what I saw before, the top of the block is clean of oil, and no leaks around the new gaskets.

I also couldn't see any run marks from the valves down. :(
 

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2X check it by taking the covers off..there really isn't anything you could have done outside of pinching the gasket that would cause that kind of leak.
 

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1991 w126 420SEL, 1986 w126 Euro 560SEC (option 822), 2000 E55, 2003 E55, 2003 SL55
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512 Posts
Could be like my trans. One seal at a time in 3 weeks I have chased leaks:)
I think he is right on the pinch. I had mine off a few weeks ago and saw nothing else that would cause it except that unless you have the above happening. Touch one thing on a 25 year old and you will touch more ;)
 

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2001 E55 AMG
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I've done these hundreds of times...it's very easy to catch the gasket and pull it off round the back while you are trying to get the VC back in place.......Little tip...stretch the gasket a bit before fitting .
 

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'83 380SEC AMG'ed euro, '92 500SL, '91 190e 2.6 5-speed
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2,389 Posts
I've had the same symptoms after a VC gasket change. I checked twice for a good fit and drove a mile and came back, HUGE oil leak. As Jono said, take off the covers again. It might be a tiny pinch towards the firewall (As it was for me). Also, the pressure that you tighten them back down at is crucial, over tightening causes them to bow out making them leak onto the exh. manifolds.
 

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1991 420SEL, 1989 Porsche 928-S4, 1973 Lincoln Continental Town Car, 1960 Lincoln Continental Mark V
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Discussion Starter #9
Sorry for the delay in updating; computer problems, sick, Murphy. :) Just to update for future DIYers;

Part of the problem was the gasket that had slipped off - it was the top front edge, virtually invisible under the fuel rail and stuff. Oh for a simple cork/paper gasket squeeze! It was on the driver's side, and I just couldn't get the gasket to stay in place while guiding the cover through the A/C lines and fuel rail.

There just wasn't enough room to get my hands to reset the gasket on the top part (of course, the curved edge) of the VC after getting the cover in place. I finally had to use a SMALL (as in infinitesimal) amount of form a gasket (blue stuff) to "glue" the gasket onto the VC. That finally kept the gasket in place so I could secure.

After all of that, it was still dripping - but with so much leaked before, I had the engine steam cleaned and then checked later. Unfortunately (for me :(), there is still a small leak at the back of the engine (I'm afraid it's the dreaded Rear Main seal).

Woe is me! ;)
 

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560SL,380SL
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I've found this VERY difficult to do right the first time, even though I have and use a 1/4" torque wrench and always install new crush washers. There are a lot o places to fail, and it only takes one little spot.
 

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Cleaning was not mentioned. If it's a small leak it may be dirt. After many miles and years dirt, varnish and grunge form around the outside of where the gaskets seal. Then since the valve covers can be moved around somewhat under the bolts, the new gasket could now be on this stuff. So replacing the gaskets includes taking a single edge razor blade (or whatever) and solvent and cleaning all around the edge of the head..
 

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1991 420SEL, 1989 Porsche 928-S4, 1973 Lincoln Continental Town Car, 1960 Lincoln Continental Mark V
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Discussion Starter #13 (Edited)
I did clean the valve head (?). There was no debris, and no scuffs, grooves, or gouges that I could see. Just oil. The head was nice a shiny alloy all the way around, and the area inside where the VC would have been was tan from oil staining. I used a lint free shop town to wipe it before inspection, then again before replacing the valve.

I did tighten the screws (obviously), but what torque should I use? I just tightened them until they were tight, but not so they could not turn anymore if I tried. I know that sounds weird, but I knew not to over tighten and risk snapping a bolt head off.

As for crush washers, thats just a simple brass washer, right? Not a lock washer? The yahoo behind the counter didn't know what I was talking about, so ... I know that sounds imbecilic, but that's always worked with other projects.
 
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