!High engine oil pressure!! But we're could the problem be ?
 

I have a c70 T5 coupe it's done 90,000 miles and been well looked after I've had it 13 yrs.
I have a problem and need some opinions to what may be the culprit
the engine oil pressure was hitting 86 psi at idol for some unknown reason
I've got it down to 48/50 psi by withdrawing some engine oil ( no it or hasn't been over filled with oil)
I'm pointing to the cylinder head because the camshafts have a chatter noise now this isn't really noticeable from looking and listening until you put your ear to the cam bearing cover this without doubt is mainly heard inside the car it's chattering from top of engine and heard through air vents across top of dash it doesn't get any louder if I rev engine and its definitely coming from engine top end
could this be a blockage of oil restriction to top end ?
Also could it be valve clearance (valve chatter)
what is causing such high oil pressure
could it be the Vvt pulley gear at fault

I will start with the condition of this engine oil flushed and changed ever 5000 miles,all compression is excellent over all 5 cylinders, pcv system has new pipes and flame trap,it has new oil pan o rings the sump has been cleaned along with pick up and the oil passes all inspected and blown through

Have you had the pcv system cleaned / renewed?

Blue 8 he says pcv and sump oil seals done... which would of been my first shout.....

Before you go further, once its good and warmed up, pull the dipstick and see if it is smoking out of it... this is a pcv pointer, which has been done, but were the ports into the block cleared too? Most likely a yes there, but thought worthy of a mench.

90k is a mere baby for these, does it do a lot of short journeys, maybe just needs a real good blow through motorway 'italian tune-up' type run?

If you have very noticeable valve chatter especially when revving harder when driving this is caused by the sump "O" rings between the two sump surfaces being dislodge or deformed and reduces oil to the head and camshaft bearings and yes, it will up the oil pressure accordingly......you may notice that the noise will suddenly go when high up in the revs sometimes but not every time as the oil pressure will overcome the blockage!

It is a very common problem on the 960 which i had with the very same problem.....the engines are identical except the 960 is the straight 6 cylinder but all same block components.

When mechanics rebuild the 960`s they always put two "O"rings in situ to make sure there is no extra room for deformation...

Oil level is not related to oil pressure unless you remove so much that the pump can't draw any through,then you won't have any pressure at all and you'll need a new engine about 30 seconds later, the big ends will start knocking.
You have a sticking pressure relief valve, probably once the oil's well warmed up it may free off and bleed off the excess pressure. You may get away with just changing the oil and filter and use the thinnest spec oil, a 5/30 grade.

Well guys some excellent thoughts there
Paul mention blow out from dipstick, there isn't any from top of camshaft where the oil goes in i have also had a latex glove over the hole and it sucks in so engine breathing system is good.I'm very intrested in the o ring situation in the sump I think it's going to be a good idea to recheck the seals

Volvo vida says 15 psi to 50 psi with blow off at I think it was 45 so therefore the blow off is at fault then if the pressure is rising above

A lot there which doesn't make a lot of sense ..

Firstly what are you measuring oil pressure with and how accurate is it ?

Where on the block are you taking the gauge oil pressure reading from ?


you said it is 86 psi @ idle , what is it at 4000 rpm at that same moment in time ? It could easily be 86 psi at idle with cold oil ,
what grade oil are you using ?

The only meaningful reading is with hot oil 100 C .. cool/cold oil can make the pressure considerably higher .

The only datum oil pressures quoted are MINIMUM pressures not maximum ...
the more pressure the better usualy, it means all the bearing tolerances are favourable . Why are you worried about it ?

You said you drained some oil out and got the pressure down by about half , oil level has no effect on Oil pressure in an engine , i suspect the oil had time to heat up in between your measurments .

Specification of the MINIMUM Oil pressure @ 100 C is :

800 rpm 0.1mpa ( 14 psi )
4000rpm 0.35 mpa ( 50 psi )

The oil pump pressure relief valve blows off at 0.48 mpa ( 69 psi )

The clattering is normal as there IS clearance between cam lobe and cam follower after model year 2000 when they did away with the hydraulic cam followers .

So basicly there is probably nothing wrong with your engine , and it will be fine for another 200,000 miles ...

Here we go ! I'm a dummy I guess or so you think what doesn't make sense

the oil pressure is measured with a oil pressure tester, expensive kit from work what is used on plant machinery .
The pressure is taken from the oil pressure switch take it out and screw in the fitting then attach the gauge.
The oil is 5-30 the pressure at cold was 85-90 psi once warm it was @70 psi I took some oil out and it was at 50 psi oil does matter cause if it was over filled then the engine pressure would pop the crank seals, so fare enough your saying 50 psi is fine relating to oil pressure ,I've had the motor a very long time and I know my engine the clattering is not normal maybe to you but certainly not to my engine why do you think the lubrication and breather system was serviced because of the chattering from head then the engine pressure was tested and believe the pressure is high and not feeding enough oil to top end

The problem is the noise from top end that's occurred for no reason so looking at the oil pressure it is ok then, like you said ,what is the chattering noise is it lifters or vvt gear or oil starvation