Chain Housing Leak-any recommended sealant?

[rrichar]

I am about to tackle the chain housing leak on my 2.7. I seem to have a leak from the flange around the cam. I haven't removed it yet but after cleaning and watching for the leak's source it seems to be coming from there. As you know I can't really see up between the housing and the cylinders. The leak continues as the engine just sits. It has leaked since I rebuilt the engine. It was put in without any sealant. I have a new gasket but wanted to insure no further leaks. What sealant would you recommend I use with the new gasket? Is there some other insights to help make sure it doesn't leak again?

[Flat6pac]

The problem is probably the rubber O ring around the retainer. When you built you might have crushed the rubber and that is the leak.
I use lots of lube on the O ring, grease and spray lube and carefully watch the rubber suck into the groove.
I coat the paper gaskets with 574, just to make sure it isnt a leak but the potential of the O ring to leak is primary

Bruce

[E Sully]

If your talking about the small paper gasket, I had a similar problem because the edge of the gasket had folded over on first install. I installed a new gasket dry and had no problems after that, but I occasionaly use a very light coat of 574 on the thin paper gaskets.

[mca]

I absolutely swore that I had a chain housing leak on my 3.0. Many times I cleaned up all of the oil from the cover and housing and watched for leaks. Still came to the same conclusion - chain housing.

Upon closer inspection (even after buying new housing gaskets) I found that it was actually leaking at the pressure sender where the sender block meets up with the engine case. Might want to take a close look here. Just a thought.

[lindy 911]

I'd bet it is the gasket; easy to get it fouled. 574 or aviation gasket maker on the thin gasket works. Be careful when you put it together and make sure its lined up before you tighten it up.

Lindy

[snbush67]

An experienced Porsche mech showed me how to trim the corners of the gasket so that it doesn't catch a corner when seating. Just clip the edges with some fingernail clippers.

I also used a thin film of 574 as mentioned above, no leaks.

Shane

[Walt Fricke]

Rob

Say a bit more here: is this a biggish leak, the kind that leaves a trail of oil when you drive the car slowly from place to place? Or is it an annoying leak, which you could ignore for a while (perhaps you have been ignoring and just cleaning up periodically)?

How long has it been this way, and is it related to any rebuild recently?

I once failed to tighten the three bolts which hold piece which has the gasket and O ring on it in place. That left a trail of oil driving the car down my driveway and into the trailer. I would think that a serious issue with the triangular gasket or the O ring would put out rather a lot of oil, but perhaps not always? The silver lining here is that this isn't a super painful fix: After you pull the muffler and the rear sheet metal, you can pull the chainbox cover, remove the tensioner, pull the gears off, and deal as needed with the cam seal parts. If you are really lucky (I was), the cam timing may not even have changed (though you'd want to check that).

If your oil pressure sender screws into a biggish steel block, all those parts are held in place by a hollow bolt, into whose end the lines to the cams are attached. Being hollow, overtorquing can crack the bolt, leading to a leak. The more you tighten, hoping to get the crush washers to work, the worse the leak at that point. But my experience has been that such a leak shows up around its local area, not back by the back of the chain boxes in where exhaust ports are.

[ChrisBennet]

I use some of that red "high tack" spray to hold the paper gasket in place on the side of the cam carrier. I believe John Walker was the origin the (high tack) idea.
Once, in a pinch, my buddy/helper made one of these gaskets with gasket material and scissors. To punch the bolt holes we used an empty .223 cartridge case as a punch!

[rrichar]

Thanks for all the ideas and suggestions.

Bruce - I will be putting in new O rings as well and will be extra careful to get enough lubrication and double check the positioning. Is Dow 111 the product of choice on the O rings?

MCA and Walt since you both mentioned it I will check the pressure senor block again, but don't think that is where it is coming from.

Walt - The leak is NOT a big one that is seen when the car is running. It is rather one that shows up after the car has sat for days. The leak is more of a garage floor problem than a serious one. Over a period of a few months there is definitely a measurable amount of oil in the drip pan on the floor.

Shane - When you say clip the edges, are you referring to the three edges/corners where the bolt holes are? Why does that help?

More than one has mentioned the folding/fouling of the paper gasket. Its been a while since I put these in: why is this happening? Isn't the gasket held in place with the three bolts as you tighten the flange?

Thanks again; more help is always appreciated.

[snbush67]

Originally Posted by rrichar

Shane - When you say clip the edges, are you referring to the three edges/corners where the bolt holes are? Why does that help?

More than one has mentioned the folding/fouling of the paper gasket. Its been a while since I put these in: why is this happening? Isn't the gasket held in place with the three bolts as you tighten the flange?

Thanks again; more help is always appreciated.

It helps if you trim just slightly so that the gasket doesn't catch an edge. You can see where this is possible as you eyeball the gasket in place. Look ath where the edges can catch and trim just a hair.

Shane

[lindy 911]

When the cam carrier is installed with the three bolts, it's important to tighten the bolts evenly. Tighten each bolt finger tight and then add a little torque to each evenly. If you tighten one all the way and then the others, the gasket can get pushed out especially if it has sealer on it to facilitate a slip. I think this is what happened to me.

Lindy