Title: PCV a possibility? Post by: newman on July 02, 2009, 03:01:01 PM Hi all, Have been noticing an excessive build up of white sludge from condensation I'm guessing, under my oil breather. I got the car in december and it wasn't there as the motor was only 15,000 mile old after reconditioning when I brought it, I have recently let my motorbike rego lapse and use the car to get to work(short distance) and I know I should walk but on wet days the car is the easy option. Can I hook up a pcv valve to fix the problem? I was thinking of coming off the back end of the rocker cover, out of sight if possible and into the intake manifold. Would this work??? Mick Title: Re: PCV a possibility? Post by: Ed on July 02, 2009, 03:12:12 PM My understanding was the PCV was a vent valve which depressurised the crank case as a result from blow by gases.
my most recent experience with white sludge under oil cap was oil mixing with water from a blown head gasket. A compression test also confirmed the head gasket was blown. get the pushy out! Cheers Ed Title: Re: PCV a possibility? Post by: newman on July 02, 2009, 03:31:45 PM I had ruled out head gasket as there is no indication of any milky residue on the dipstick, just as I said a milky brownish residue under the oil breather. I have always found tell tale signs on the dipstick when head gaskets fail, is this wrong? Title: Re: PCV a possibility? Post by: CraigA on July 02, 2009, 03:44:28 PM Do you do a lot of short trips? Possibly its just condensation forming under the rocker cover due to the difference between ambient and engine temps, and then does evaporating because the engine (or motor) isn't running ong enough to burn it off completely.
Like Ed says a compression test combined with a cooking system pressure test should tell you if its a blown head gasket or not. If its a newish engine did it ever have the head retensioned? Would be worth checking by putting a torque wrench on them and checking the head bolts are set right. Besides all that, its a Holden 6 so you just keep driving it until it stops. Then you fix it. Title: Re: PCV a possibility? Post by: CraigA on July 02, 2009, 03:45:29 PM That'd be cooling system, not cooking system............ :P
Bloody no edit function. Title: Re: PCV a possibility? Post by: Ed on July 02, 2009, 03:50:46 PM Newman, Would also depend where the gasket breaks. In my case between 2 cylinders and water jacket. No milkiness on the stick, drove and idled reasonably well just a barely noticeable milky residue when cold under the oil cap. Knew it was probably broken since it was losing water, so verified with a compression test showing a 30psi drop on 2 of the cylinders.. bingo.
but as Craig says could be just condensation from very short trips. Cheers Ed Title: Re: PCV a possibility? Post by: newman on July 02, 2009, 03:53:29 PM Craig and Ed,
Guilty as charged, the drive to work is only 2k's and I do warm the grey up for about 5 minutes so YES it is doing short trips. Would a pcv valve help with the condensation issue? I will do a compression check but the motor really does go well so I'd be surprised if it is down on compression (But it won't hurt to check and establish a set of reference figures for any future compression checks) Mick Has anyone got a pcv setup on their grey motors????? Title: Re: PCV a possibility? Post by: Ed on July 02, 2009, 03:59:04 PM No i dont think a PCV will help.
just drive it longer to burn up the moisture. Title: Re: PCV a possibility? Post by: newman on July 02, 2009, 04:11:32 PM Thanks for the input guys, I will use the car less for going to work and walk, and I'll do that compression check this weekend. ;) Title: Re: PCV a possibility? Post by: Ed on July 02, 2009, 04:13:02 PM re-reading your original post...
the air going in thru the breather on the rocker cover is an intake (letting air in to equalise), while simultaneously blow by gases are exhausted via the "walking cane". you shouldnt be getting excessive pressures up in the rocker area if your cane is not blocked, so a PCV plumbed here would not do anything. Pressure is built up in the bottom end (below the rings). you need heat to evaporate off the condensate. Cheers Ed |