1994 Volvo 850 Turbo Cam cover Vent hole plugged....

jackwagon · Post by **jackwagon** » 26 Jan 2016, 23:02

I recently bought a 94' 855 turbo and have been updating everything due to necessity. unfortunately I knew nothing about engine mechanics before I bought this car and still have learning to do. Any input is appreciated.

I replaced the PCV system as there was a lot of blow by and even after there was continued blow by. Ran Seafoam through the gas tank and crank case which appears to have solved the dipstick blow by as of tonight after a bit of driving today.

My question is in regards to this plugged hole in the top of the engine. I am the 3rd owner and have had to fix a lot of the previous owners jimmy rigging (why anyone would do the work on a car just to make more for themselves I have no clue) and see this as a possible addition to the list. After new PCV and seafoam treatment the dipstick blow by is not present, but there seems to be oil still leaking in the plug cover area and around the seems of the engine (probably the Head Gasket). If I unplug this hole will that reduce bad engine pressure and improve efficiency? or will it increase leakage and cause more shop time or jack stands?

Car runs fine as of right now. just leaky oil and low compression. 169xxx

here's a pic:

Post by **erikv11** » 26 Jan 2016, 23:50

That hole just has flat head surface underneath it, that poty is not used on these engines and not really a hole. In some 93 and/or early 94 setups it was used, but I have sketchy knowledge of those engines, and clearly it is not used on yours. If the cam cover is sealed properly then there is no leakage out of that location.

: one clean engine

You may have one of those DIY gems where the cam cover is sealed with RTV silicone instead of anaerobic sealer? Check the edges of the cam cover.

Post by **tryingbe** » 27 Jan 2016, 05:19

Your oil cap seal needs to be change. If you decide to get a new oil cap, STAY AWAY FROM MOTORAD CAP, it will leak from new.

Post by **dosbricks** » 27 Jan 2016, 09:35

Welcome to the forum, jack.
I agree with tryingbe, your oil leak appears to be primarily due to an old hardened oil filler cap seal. The Volvo OE seal will outlast all others:
https://www.fcpeuro.com/products/volvo- ... 850-940096

This is considered a regular maintenance item to be changed every 40-50k.

jackwagon · Post by **jackwagon** » 07 Feb 2016, 12:38

Will look into another oil cap, the one I have on her is new so if its cruddy that may be the case. The sealant seems to be red/pink/orange from the looks. Another problem I have considered is this....

There are miss match bolts in the cam cover and some have a 13mm hex head with 10.9 rating. The others are what appear to be reused head bolts. If anybody has any insight on how likely missthreadin is in this situation it would be appreciated.

I need to turn on notifications for this site. Wish I saw these replies sooner haha

jackwagon · Post by **jackwagon** » 07 Feb 2016, 12:44

dosbricks wrote:Welcome to the forum, jack.
I agree with tryingbe, your oil leak appears to be primarily due to an old hardened oil filler cap seal. The Volvo OE seal will outlast all others:
https://www.fcpeuro.com/products/volvo- ... 850-940096

This is considered a regular maintenance item to be changed every 40-50k.

I got a Stant cap which came with the seal. Not sure if thats a good one or not.

Post by **erikv11** » 07 Feb 2016, 16:14

That is definitely silicone there in the hole. It is not needed but is not harming anything, I would just leave it there.

But around the edges of the cam cover, is it the same rubbery sealant, can you tell?

The cover bolts are easily over tightened, but offhand who knows maybe they are on properly. Again I would leave them alone for now. Clean up all the oil real well then see where it is coming from. No opinion here on the Stant cap, have never used one.