Oil leaking from Filler Cap

becdavies · Post by **becdavies** » 25 Apr 2021, 02:51

I’ve got oil starting to leak / pressurise out of the filler cap.
Originally I had a leak and found the cap o ring was very dry so got a new cap / o ring. It solved the issue.
But now a few weeks later I’m getting the same issue happening again. The o ring is fine however does appear to be moving very freely when I take the cap off so that could be it and not creating a very good seal?

I’ve done the Pcv glove test and it sucks in which is good and no smoke from dip stick or exhaust.
Is the O ring supposed to move freely when the cap is off or supposed to be fairly solid?

Are there any other causes of oil leaks from the Filler?
The only thing I’ve changed is had to change the oil to a 10W-40 to slow an oil leak from the cam seal for a month till I get it fixed (the oil is still recommended in the book)

XC70Rider · Post by **XC70Rider** » 25 Apr 2021, 07:06

The oil cap gasket is common to break and cause an oil leak. They're cheap and easy to replace with a pick or mini screwdriver.

https://www.fcpeuro.com/products/volvo- ... -1275379oe

With the filler neck being wide and shallow I also spilled fresh oil on my valve cover until I got this funnel a year ago. Since then the valve cover has remained clean.

https://www.fcpeuro.com/products/europe ... nospillkit

Post by **ljsommar1** » 25 Apr 2021, 07:50

IPD sells a Viton neoprene oil cap seal. It seals better and will probably last longer than the car.
Mine was leaking, I replaced the original about 10 years ago with that one, problem solved.

becdavies · Post by **becdavies** » 25 Apr 2021, 11:15

XC70Rider wrote: ↑25 Apr 2021, 07:06 The oil cap gasket is common to break and cause an oil leak. They're cheap and easy to replace with a pick or mini screwdriver.

https://www.fcpeuro.com/products/volvo- ... -1275379oe

With the filler neck being wide and shallow I also spilled fresh oil on my valve cover until I got this funnel a year ago. Since then the valve cover has remained clean.

https://www.fcpeuro.com/products/europe ... nospillkit

It’s not being spilt when I filled as it appeared after.
And the oil cap gasket break within a matter of a couple of weeks? I thought they would last longer than that? The seal looks pretty good but it does move around freely so that’s where it’s likely not making a good seal when put on.

cbpitt01 · Post by **cbpitt01** » 26 Apr 2021, 21:00

becdavies wrote: ↑25 Apr 2021, 02:51 I’ve got oil starting to leak / pressurise out of the filler cap.
Originally I had a leak and found the cap o ring was very dry so got a new cap / o ring. It solved the issue.
But now a few weeks later I’m getting the same issue happening again. The o ring is fine however does appear to be moving very freely when I take the cap off so that could be it and not creating a very good seal?

I’ve done the Pcv glove test and it sucks in which is good and no smoke from dip stick or exhaust.
Is the O ring supposed to move freely when the cap is off or supposed to be fairly solid?

Are there any other causes of oil leaks from the Filler?
The only thing I’ve changed is had to change the oil to a 10W-40 to slow an oil leak from the cam seal for a month till I get it fixed (the oil is still recommended in the book)

It sounds like the gasket ring you’ve used may not be the correct inside and/or outside diameter. I got half a dozen aftermarket ones from either ipdUSA or fcpEuro (can’t remember which) when they were on clearance for about 60 cents, and they fit very snug on the underside of the cap - they don’t wiggle or spin around at all.

Post by **MoVolvos** » 26 Apr 2021, 21:10

*
The gasket could shear / stretch or flatten slightly when all surfaces are absolutely dry / oil free when turning to tighten. Should have a little slickness when in use much like a little lubrication on an oil filter gasket when installing. Might be able to bend the tabs to provide a better / snugger fit. Shouldn't be moving / sliding unless you are really pushing or pulling hard.

*

darylrobert · Post by **darylrobert** » 27 Apr 2021, 06:08

try a new filler cap, the seal shouldnt be loose.

Post by **erikv11** » 27 Apr 2021, 08:43

A few things to consider:

- You could try bending the tabs on the fill cap slightly upward, which will pull the top of the cap down tighter when it is installed.

- Is it a really cheap-o gasket and moves more on the cap because it is thinner than normal? I've found the Volvo branded gaskets ($5 each) last about three times as long as the generic ones ($0.68 each), so quality indeed makes a difference. The Viton gasket sounds interesting, wasn't aware of that.

- A replacement fill cap is also not a bad idea given how easy that route is; I'd get one from the junkyard. All P80 and P2 engines (and others) use the same cap - almost any Volvo at the yard has it.