BMW E46 Fanatics Forum banner

1 - 20 of 35 Posts

·
Registered
2002 BMW 325I with 175k miles
Joined
·
149 Posts
Discussion Starter #1
I'm sure there are a ton of these in here, but I felt like I did the valve cover gasket really well. I tightened them down well, got a new/used valve cover itself from an XI that had around 70-80k miles on it. And even used some RTV. But it's leaking from the back left and onto the sensor that's attached to the top of the manifold. Should I take it off and just put some RTV in that area?
 

·
Registered
2005 BMW 330i
Joined
·
713 Posts
What brand gasket
 

·
Registered
Joined
·
4,068 Posts
I'm sure there are a ton of these in here, but I felt like I did the valve cover gasket really well. I tightened them down well, got a new/used valve cover itself from an XI that had around 70-80k miles on it. And even used some RTV. But it's leaking from the back left and onto the sensor that's attached to the top of the manifold. Should I take it off and just put some RTV in that area?
The left side cover sit higher than the right side which all the oil pooled on this side; I don't see why the leak is on higher side instead of lower side. What sensor attached to the top of intake?

where did you add the RTV, and how thick?

Last week I removed the VC off my 2003 525iT to investigate a small leak at front right (on top of EX cam sensor); a drop or two on ground every trip. Turned out the PO added too much RTV on the area and all the half-moon pieces causing uneven sealing surface. I removed and cleaned all, reused the old gasket and added a thin RTV, on the head and not the gasket, at the half-moon pieces and the 2 seams where vanos contacts the head. Leak free now.
 

·
Registered
2002 BMW 325I with 175k miles
Joined
·
149 Posts
Discussion Starter #4
The left side cover sit higher than the right side which all the oil pooled on this side; I don't see why the leak is on higher side instead of lower side. What sensor attached to the top of intake?

where did you add the RTV, and how thick?

Last week I removed the VC off my 2003 525iT to investigate a small leak at front right (on top of EX cam sensor); a drop or two on ground every trip. Turned out the PO added too much RTV on the area and all the half-moon pieces causing uneven sealing surface. I removed and cleaned all, reused the old gasket and added a thin RTV, on the head and not the gasket, at the half-moon pieces and the 2 seams where vanos contacts the head. Leak free now.
Interesting, I took a microfiber cloth with brake fluid and cleaned off the surface and I only put a small dab of RTV at the Semi Circles.
 

·
Registered
E46 '04 330Ci convertible 760 K km
Joined
·
1,415 Posts
Elring gasket with new screws and washers and gaskets for the screws
Even low quality gasket, if new, will seal cover properly, it jsut won't last. Elring is good one.
If you replaced gasket AND all rubber grommets with new ones, and applied tiny amount of silicon sealer on corners of VANOS, then it shouldn't leak at all. Tighting nuts more won't change anything. It is possible that your cover has cracks. You probably should remove it again, clean everything and inspect closely. Do not use RTV anywhere else but those VANOS corners and on lines where timing belt cover mates head (as on that pic from google, just apply less amount)

919214
 

·
Registered
Joined
·
4,068 Posts
Even low quality gasket, if new, will seal cover properly, it jsut won't last. Elring is good one.
If you replaced gasket AND all rubber grommets with new ones, and applied tiny amount of silicon sealer on corners of VANOS, then it shouldn't leak at all. Tighting nuts more won't change anything. It is possible that your cover has cracks. You probably should remove it again, clean everything and inspect closely. Do not use RTV anywhere else but those VANOS corners and on lines where timing belt cover mates head (as on that pic from google, just apply less amount)

View attachment 919214
1) I think you forgot the rear 2 half-moon areas on the head -- just same as on the vanos.
2) One important point is don't wait too long or the RTV got firm then the gasket cannot flatten the glue, causing uneven gaps and leak. The reason to add RTV only to the metal surfaces and not to the gasket is easier to control how thin the added RTV.

This picture is an example of adding too much RTV and will cause gaps and leak.
 

·
Registered
E46 '04 330Ci convertible 760 K km
Joined
·
1,415 Posts
1) I think you forgot the rear 2 half-moon areas on the head -- just same as on the vanos.
I did forget, in fact.
And, as mentioned, as tiny amount as possible, excess won't help at all but can end up travelling inside engine.
 

·
Registered
2002 BMW 325I with 175k miles
Joined
·
149 Posts
Discussion Starter #10
1) I think you forgot the rear 2 half-moon areas on the head -- just same as on the vanos.
2) One important point is don't wait too long or the RTV got firm then the gasket cannot flatten the glue, causing uneven gaps and leak. The reason to add RTV only to the metal surfaces and not to the gasket is easier to control how thin the added RTV.

This picture is an example of adding too much RTV and will cause gaps and leak.
So put less RTV then on those pictures, and put them on the back of the valve cover too? Got it!
 

·
Registered
E30M3 Race F10 535 R1150Rt M Coupe
Joined
·
3,584 Posts
Curious as to why you needed to replace the VC itself.
Insofar as brands of gasket: Dealer, Elring.
For those that don't do this sort of thing everyday like I do, carefully move the O2 wires and SAP vacuum hose so they can't get in between. Lay the cover on the head and then take an inspection mirror and light and spend a minute (really a minute) looking around the back and the half moons. Look 110%? Press on.

Valve covers in general for the E46 are robust, could be a hairline crack. My money is on an old hardened piece of gasket.
 

·
Registered
2002 BMW 325I with 175k miles
Joined
·
149 Posts
Discussion Starter #14
Curious as to why you needed to replace the VC itself.
Insofar as brands of gasket: Dealer, Elring.
For those that don't do this sort of thing everyday like I do, carefully move the O2 wires and SAP vacuum hose so they can't get in between. Lay the cover on the head and then take an inspection mirror and light and spend a minute (really a minute) looking around the back and the half moons. Look 110%? Press on.

Valve covers in general for the E46 are robust, could be a hairline crack. My money is on an old hardened piece of gasket.
I replaced the original because it had 179k miles on it and I just assumed it would be warped. And the gasket is brand new, I don't think it's a hard piece. But before it definitely was, couldn't even get it off with putting a knife/screwdriver to the old gasket.
 

·
Registered
E46 F10 W204 W212
Joined
·
5,118 Posts
I'm sure there are a ton of these in here, but I felt like I did the valve cover gasket really well. I tightened them down well, got a new/used valve cover itself from an XI that had around 70-80k miles on it. And even used some RTV. But it's leaking from the back left and onto the sensor that's attached to the top of the manifold. Should I take it off and just put some RTV in that area?
Make sure you didn't pinch the oxygen sensor wire on install. It's happened to a few here.
 

·
Registered
2006 330ci zhp
Joined
·
2,046 Posts
I'm sure there are a ton of these in here, but I felt like I did the valve cover gasket really well. I tightened them down well, got a new/used valve cover itself from an XI that had around 70-80k miles on it. And even used some RTV. But it's leaking from the back left and onto the sensor that's attached to the top of the manifold. Should I take it off and just put some RTV in that area?
Are you saying left side as you are looking at the engine? The manifold is the exhaust manifold and the sensor is the O2 sensor? It does make more sense the valve cover would leak back there. That's where oil would sit.
 

·
Registered
2002 BMW 325I with 175k miles
Joined
·
149 Posts
Discussion Starter #20
Are you saying left side as you are looking at the engine? The manifold is the exhaust manifold and the sensor is the O2 sensor? It does make more sense the valve cover would leak back there. That's where oil would sit.
919275

Leaking right here onto this sensor. Probably O2
 
1 - 20 of 35 Posts
Top