Camshaft seals keep going bad

[50313]

Camshaft seals keep going bad
I rebuilt my engine for my '03 P5 earlier this year (I'll spare you the saga) and all was right with the world.

A few months later I noticed that it was leaking a fair amount of oil. Since the leak was behind the timing belt cover, it was hard to tell exactly where it was coming from. Not having the time to diagnose and needing to get the car back on the road asap, I took it to the mechanic and they said the issue was the camshaft seals. I had them replaced, the oil leak stopped, and again all was right with the world.

Fast forward to a couple of days ago, and I again noticed a pretty decent amount of oil leaking from the car. Again, it looks like it's coming from behind the timing cover.

What are the chances that the issue is with the camshaft seals again? Is there a known issue with the camshaft seals on these cars?

If if is the same problem as last time I'd love to fix it myself and save some money. However I'd also like to fix it and not have it happen again. This could really get old if it turns into a quartly project.

Thanks,

-peel

 

[CheeseHelmet]

Maybe when the camshaft seals were originally replaced, one of the shafts was scored. If the scoring was bad enough it might be chewing-up the new seals.

If that is the problem (the only way to tell it by inspecting it yourself), I heard you can repair scores like that by filing-down the effected area, then filling the scores with JB Weld and finally filing it again until it's smooth.

 

[50313]

Hadn't thought of that but it makes perfect sense. I was having trouble figuring out what it would be that could be causing them to go bad, but I was thinking about the outside of the seal, not the inside. Since I didn't ask how or in what manner the seals went bad last time, I'll probably end up pulling the cover and checking them out myself tomorrow.

So here's hoping it's the seals, and the cause of the failure is somewhat obvious. If it's something else, it will certainly ruin my day (mad)

Thanks for the reply,

-peel

 

[MaxPower]

Did you remove the cam cap that goes over the cam seal? If so, it's pretty tricky to put it back on--if you just bolt it on, you'll probably get a leak from the sealing surface between the cap and head (the oil here is under pressure). And simply putting silicone on the sealing surface might not seal it correctly. Replacing the cam seals will not correct this problem. I'm not sure exactly how to fix it. When this happened to my car, my mechanic machined the head/cam cap and used some special sealant recommended to him by a machinist.

 

[CheeseHelmet]

Did you remove the cam cap that goes over the cam seal? If so, it's pretty tricky to put it back on--if you just bolt it on, you'll probably get a leak from the sealing surface between the cap and head (the oil here is under pressure). And simply putting silicone on the sealing surface might not seal it correctly. Replacing the cam seals will not correct this problem. I'm not sure exactly how to fix it. When this happened to my car, my mechanic machined the head/cam cap and used some special sealant recommended to him by a machinist.

Are you referring to those little spots of RTV that you're supposed to apply to the head before putting the valve cover back on? That's not a bad idea

 

[MaxPower]

Are you referring to those little spots of RTV that you're supposed to apply to the head before putting the valve cover back on? That's not a bad idea

[EDITED]
No, that's not what I'm referring to. You are referring to the RTV that is applied just adjacent to the cam cap, which seals the valve cover gasket/head.

There is a cap that goes OVER the cam seal. If it is removed, its flanges need to be sealed correctly when the cap is bolted back on or it will leak (the oil is under pressure here).

 

[CheeseHelmet]

Yes, but you have to be careful to apply the RTV correctly. I had applied RTV, but apparently the oil was still able to push its way through... I'm not sure exactly what I did wrong, but it did create quite an oil leak.

I followed the diagram in the service manual and so far I don't have any leaks.

 

[50313]

Thanks again for all the info. I didn't have time today, our refrigerator decided to quit working (looks like the thermostat bugged out cause the condenser was frozen solid), but I plan on tackling this tomorrow.

One additional question, what type of RTV should I use. The book just says Silicone Sealant, and I've never found a good guide that describes the differences between the different types of RTV or lists which one should be used for what. I've only ever found temp ratings on the packages that give any real indication as to the application.

Take care,

-peel

 

[CheeseHelmet]

One additional question, what type of RTV should I use. The book just says Silicone Sealant, and I've never found a good guide that describes the differences between the different types of RTV or lists which one should be used for what. I've only ever found temp ratings on the packages that give any real indication as to the application.

"Grey" RTV is what you need: http://www.permatex.com/products/Au...gid_High-Torque_RTV_Silicone_Gasket_Maker.htm

It's used for the oil pan gasket too.

 

[flash75]

I would use a sensor safe RTV. The grey RTV doesn't appear to be sensor safe.

http://www.permatex.com/products/Au...Sensor-Safe_High-Temp_RTV_Silicone_Gasket.htm

Clifton

 

[bucksatan]

I used "ultra grey", it is sensor safe. Been a year now and haven't noticed any oil leaks.

Also, remember not to tighten down the valve cover bolts too much, it will distort the cover and this will results in leaks. The torque specs are quite low on the cover.

 

[flash75]

"I used "ultra grey", it is sensor safe. Been a year now and haven't noticed any oil leaks. "

I wonder why the description doesn't say it's sensor safe? I would think it's advantageous to state
a product is sensor safe. I don't buy products for engine use unless it is listed as sender safe.

Clifton

 

[bucksatan]

I'm pretty sure the cardboard backing on the blister says it is sensor safe. Of course I no longer have the cardboard backing. But the picture I found online says it is.

Also, torque specs on the bolts is 60 to 90 INCH pounds. INCH, not foot. You can take my word on it that it is easy to snap one of those bolts if you tighten them too much.

Picture of the ultra grey package:

 

[CheeseHelmet]

I wonder why the description doesn't say it's sensor safe? I would think it's advantageous to state
a product is sensor safe. I don't buy products for engine use unless it is listed as sender safe.

Dumb question: what does "sensor safe" mean?

 

[flash75]

It means the product is safe to use in/on engines with oxygen sensors.
Normal RTV can contimate sensors, sensor safe RTV shouldn't affect sensors.

Clifton

 

[Dermen]

I used Ultra-Black for "Maximum Oil Resistance"

 

[MaxPower]

Misread the thread and had to make some changes to my 10-09-2010 posting.