Oil leak at front of camshaft

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sgnimj96
Turbo Charger
Posts: 266
Joined: Thu Feb 20, 2014 2:08 pm

Oil leak at front of camshaft

Post by sgnimj96 »

This CY engine isn't very old but I don't know who built it.
Oil has been leaking out of the top since I first started it.
I thought it was the valve cover, then the head gasket, but
finally last night I had cleaned it up and did a short trip,
and was lucky to see it through the cam sprocket with a mirror right
on the middle of the cam seal.
Small black stream running down the bottom of the cam front seal.
It even keeps leaking for a few minutes AFTER the engine is shut off.

I probably ruined my valve cover gasket thinking that was it, overtightening,
but a new one is coming tomorrrow.

I'm thinking maybe the #1 cam cap doesn't have any sealant or the cam seal was installed wrong.

What's the correct way to do this? Remove the cap and give it a little hylomar spray?
Not much covering this topic.
Seems like the easiest thing to try first.
I see the torque is pretty low on those caps, and I better not put on backwards.

Also wondering if this has had an effect on my oil pressure.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
Fatmobile
Global Moderator
Posts: 7570
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Oil leak at front of camshaft

Post by Fatmobile »

You won't put the #1 cap on wrong.

There is a sealant, I'd have to check my tube but I think it is #2.
My mechanic used to call it aviation sealant.
It is kind of dark brown and never hardens.
I started putting a thin film of it on the #1 cam cap surface,
where it's metal on metal.
I used to always have a cam leak until Libby posted how he seals the cap pressure.

On the TDIs they put a channel in the cap that would keep the pressure from the bearings, from traveling between the halves and up beside the seal.

I used a TDI cam seal on the last engine.
It was skinny and sat way deeper and sealed in a different place than the worn area.

I also started putting some right stuff in the corners where the valve cover seal sits.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
sgnimj96
Turbo Charger
Posts: 266
Joined: Thu Feb 20, 2014 2:08 pm

Re: Oil leak at front of camshaft

Post by sgnimj96 »

Thanks for the help on this.
It's an oddly missed discussion of the IDI pages.
Sounds like Permatex form-a-gasket #2.

I can see how people miss this area leaking because it
is blocked visually by the sprocket, but shows down on
corner of the head. It wasn't till I cleaned behind the sprocket
with a thin towel, ran it, looked with a mirror AND the the seal
was visible because of the position of the sprocket. A thin line
running down the head from the bottom of the cam seal.


Up until then I thought it was leaking from the
valve cover or the head gasket
at the big oil drain in the corner.

I was already pricing head gaskets thinking that must be it..., yikes.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
Fatmobile
Global Moderator
Posts: 7570
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Oil leak at front of camshaft

Post by Fatmobile »

Right, that could be it. Permatex #2.
I always thought part of the problem was the cam tapering right up to the seal.
It doesn't look like the outer lip of the seal is even touching the cam.
So it was nice to see the TDI cam seal sit so deep.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
sgnimj96
Turbo Charger
Posts: 266
Joined: Thu Feb 20, 2014 2:08 pm

Re: Oil leak at front of camshaft

Post by sgnimj96 »

Sure enough when I got the #1 cam cap off
there was no sealant. Was so glad to to see that.
That leak is finally fixed ! Thanks for the verification.

Whoever built the head just didn't know. I guess it
is an unusal thing that a cam cap is on the outside of
the head like that? Seems like this would
be more discussed. Like a few others, all I found was an
obscure reference from Andrew from long ago.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
Fatmobile
Global Moderator
Posts: 7570
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Oil leak at front of camshaft

Post by Fatmobile »

Yep, that's how I first heard of it.
I thought I had a picture of the TDI cap setup and how it drains the pressure.
But can't find it.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
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