Expert: Ray Niemi - 2/19/2007

Question
I have a 95 850 non-turbo with 150K that had to have a new head installed
when I lost compression and the check engine light came on.  The mechanic
(a certified Volvo specialist) told me the valves and spark plugs were very
burnt.  The car was recently serviced before the incident, and was running
great.  It did use oil, about a quart every 1K, which I took to mean it would
need a valve job soon, so I was not suprised.  However, since then, the engine
makes noise that sounds like the tappets, under moderate or higher
acceleration, and only wile driving.  I cannot make it do it just with revving at
idle.  I was told that an oil supply problem is the likely culprit of the head's
demise, and that i should have the oil pan o rings and sump replaced to
prevent the new head from being damaged.  I took it in to a mech (not a
Volvo Spec) that checked the oil pressure, but only at idle, and it came up
very good.  I have had the fuel system cleaned, thinking at first is was
knocking/pinging, and use 91-93 octane premium always.  So, my question,
do you think it is the (lack of) oil supply causing the noise, or what?

Thanks a lot!!!
Confused and desperate...

Answer
Andy,
Oil pressure maybe up to par, but is it able to supply the upper engine with all the oil needed. That may mean that the pick up seals are not sealing and sucking air in and not suppling the needed oil. One test is to get engine fully heated (like a test drive) and idle the car remove the oil cap and see if there are any bubbles in the oil.