Cam seal leaking after replacement

[Eyebrows123]

My front cam seal has always leaked since owning my Volvo 940 1996 B230FK but recently it's got slightly worse. Long story short, it's caused the water pump seal to once and it's now about to go a second time (lasted 1 year). I replaced the cam seal about 2 years when I did the head but it still seems to leak a little. 2 years ago I used an aftermarket seal (when I did the headgasket), it seemed to leak a bit so I replaced it 2 weeks later with a genuine Volvo one, however, it's still leaking so I really need to do something about it.

What would cause them both to leak, am I putting them in wrong? From memory I put them in gently with a perfectly fitting socket (all oiled up) until about 2 mm below flush. Also may be worth noting I replaced the PCV breather box as well. Could I somehow have too much crank case pressure something be wrong? (When idling there's a vacuum at the valve cover, it pulls my glove in fairly strong).

Should i just go ahead and replace the seal and hope that solves the problem or do we think something else is causing it?

Hope someone could help, would be very much appreciated

[TonyS9]

Blocked or collapsing breather system?

Is it a turbo? They tend to push oil out on the dump because there is no check valve, especially if you are running extra boost.

[Eyebrows123]

Possibly. Where is it likely to be blocked/collapsed and how could I check it? As mentioned before the breather box was replaced about 2 years ago so would be surprised if it was gummed up already.

I'm not running extra boost but again, what's the easiest way to check or sort this?

[TonyS9]

-Is there a wear lip/dent on the cam seal area? it maybe better to avoid the area and leave it flushish. Or maybe flush is the requirement and the seal lip is missing the end of the cam. Unless the cam is damaged it should not be a big problem.

-There is no one place for blockages with the turbo engines, but if you are getting suction at the oil filler it should be ok in normal running.

-During power you might get collapsing of some breather pipe if it is very soft, the big pipe should be semi rigid vinyl and should not collapse.

-I've fitted a 16mm check valve to mine in the big pipe to stop the dump pressure getting in the crank case, makes the engine much cleaner generally. But I am running over boost and getting oil splashing the egnine bay in every seal area (eg the cam cover and oil filler), but I am using a soft pipe and it is collapsing so I need the vinyl one really.

[Laird Scooby]

Originally Posted by Eyebrows123

My front cam seal has always leaked since owning my Volvo 940 1996 B230FK but recently it's got slightly worse. Long story short, it's caused the water pump seal to once and it's now about to go a second time (lasted 1 year). I replaced the cam seal about 2 years when I did the head but it still seems to leak a little. 2 years ago I used an aftermarket seal (when I did the headgasket), it seemed to leak a bit so I replaced it 2 weeks later with a genuine Volvo one, however, it's still leaking so I really need to do something about it.

What would cause them both to leak, am I putting them in wrong? From memory I put them in gently with a perfectly fitting socket (all oiled up) until about 2 mm below flush. Also may be worth noting I replaced the PCV breather box as well. Could I somehow have too much crank case pressure something be wrong? (When idling there's a vacuum at the valve cover, it pulls my glove in fairly strong).

Should i just go ahead and replace the seal and hope that solves the problem or do we think something else is causing it?

Hope someone could help, would be very much appreciated

This might be a silly question, but which way round are you fitting the seal? With the lip of it pointing inwards towards the cam?

Are there any burrs on the leading edge of the cam (perhaps the keyway for the pulley key?) that could snag the seal as it's fitted?

Also have you checked the surface of the cam where it enters the seal, not just for a groove worn in it as suggested already but for a build-up of gum/varnish from oil over the years? IF so that needs cleaning off as it might be that causing the leak.

If you think it may be the keyway snagging the seal as you fit it (it only needs a tiny nick out of it to leak) wrap some insulating tape round the end of the cam to protect the seal from the keyway, obviously removing the tape after fitting the seal.

If all that is as it should be, maybe you've just been unlucky with the seal but it sounds as if there is something there that is causing a repeat problem.

[lnparry]

My 940 has leaked from the front seal since I bought it 4 years ago. I tend to wipe down the area every few weeks but have been considering changing the seal for a while.

Some good tips above but is this common on 940s? My 740 never lost a drop of oil from here in 13 years ownership.

LeeP

[lnparry]

Should have added it is a late '97 LPT and I cleaned out the breather system when I first got it as it was clogged.
LeeP

[Eyebrows123]

Thanks for all the replies. I might try have a go at it today.

The cam seal fits lip side inwards correct? (Just checking it's not me doing something stupid here!)

I'll check for any burrs and snags but I didn't see any last time from memory. I'll check once more, it could be that it just slipped a bit far or something nicked it. Hopefully anyway!

[Laird Scooby]

Originally Posted by Eyebrows123

Thanks for all the replies. I might try have a go at it today.

The cam seal fits lip side inwards correct? (Just checking it's not me doing something stupid here!)

I'll check for any burrs and snags but I didn't see any last time from memory. I'll check once more, it could be that it just slipped a bit far or something nicked it. Hopefully anyway!

Yes, that's correct on the seal and why i asked the question. Seen some strange things over the years and just wanted to check.

Also after doing a bit more checking myself, there isn't a Woodruff key in the camshaft to align the pulley, it's a dowel in the end of the cam that aligns the pulley so you can also discount the suggestions of tape over the end of the cam when fitting the seal.

I'd suggest fitting the next seal flush, rather than tapping it all the way in, just to move the lip further forward on the cam and prevent any possibility of the seal distorting through being compressed where it wasn't designed to be. If everything is spotlessly clean, new seal well lubed, no obvious marks/burrs etc on the cam then i think you've just been unlucky with the seals.

[Eyebrows123]

Thanks, yeh as I thought really

Just a thought, could it be to do with the point where the bearing cap and head meet? The shut line there may let oil around or is it unlikely?