Disappearing Oil, 1998 V70t5

MisterLister · Post by **MisterLister** » 24 Jan 2007, 08:46

hi all
a bit of history
just before xmas the v70 head gasket had a leak and the upper heater matrix hose near to the engine block had a hole blown through it.
I have since replaced the following: head gasket plus all other head relating gaskets, head bolts, sparkplug well o rings, camshaft seals (even the one behind the exhaust variable timing pulley), both belts and tensioners, the pcv oil seperator, the heater matrix hose, oil filter and oil.
all the time giving all the compnents a full clean and inspection. including the turbo unit and ETM.

the problem
after a few weeks of running perfectly (even better than before because it use to hunt at juctions, lights etc, and be very smoky when putting the pedal to the floor) and still runs great apart from the oil is now disappearing from the sump into the coolant expansion bottle. the condition of the oil in the expansion bottle is as new it has not even starting to turn into milkshake.
the coolant system becomes over pressurized with the extra fluid and escapes through the cap, as it should.
the coolant system keeps its pressure even after leaving it overnight.
i am talking about 1 litre of oil for every 100 miles traveled.
there is no water within the oil system, i have drained this twice now thinking that if oil is going into the water it should also be traveling the other way but it is not. there is no smell or sign of oil in/from the exhaust system.

question: what is going on? why is there oil in the coolant system but not the other way.

thankyou for your time reading this, any help in solving this would be great. i am pulling my hair out (did not have much to start with) trying to find where the oil is entering the coolant system.

Mark

Post by **MadeInJapan** » 24 Jan 2007, 19:12

That's a tough one...I'll let one of our resident experts tackle this one...maybe Bill. My first guess is that you have a bad radiator and the oil is crossing over inside of it, or you have one of the lines routed wrong...oil return line to the coolant, for instance.

Post by **billofdurham** » 25 Jan 2007, 12:40

I'll let one of our resident experts tackle this one...maybe Bill.

Thanks, MIJ. Like Mark I have very little hair left and I have now lost more trying to solve this one.

Mark, I have heard of one way transfer of oil due to a problem with the head gasket, but it was not the amount of oil loss you are experiencing.

My friendly Volvo man has had experience of this but, again, not with such a large loss of oil.

He has suggested that there is a build up of pressure in the engine which is forcing the oil into the water. Normally such over-pressure would force an oil seal but he thinks that the head gasket may not have been seated properly, or the head itself was warped and the oil is leaving that way. He also said that over-pressure could be the reason water is not transferring into the oil.

Sorry I can't be more helpful but I can't find anything else in any of my, or his, books.

Bill.

Post by **MadeInJapan** » 25 Jan 2007, 13:24

Bill, over-pressure meaning a clogged PCV system?

Post by **billofdurham** » 25 Jan 2007, 15:16

Sorry. Yes, that would be the most likely cause.

Bill.

MisterLister · Post by **MisterLister** » 25 Jan 2007, 15:43

thankyou for the replies
i had replaced the oil separtor and cleaned all assoc tubes including the very thin one that come from the oil sep to the inlet manifold, which was so blocked that i had to put a drill bit through the build up.
i spent 2 hours measuring a number of places on the head and the top of the block for any warpage, the haynes manual says 0.5mm across the length and 0.2mm across the width; i found 1 point where i could measure 0.01mm all other places where spot on flat or so small the 0.01mm feeler gauge would not slide under. the head gasket went on fine, got it the right way up and all the holes in the gasket matching the head.
i have heard of over pressure in the oil system but i thought the oil pressure release valve was meant to stop that unless of cause it is faulty.
is there any way of testing it?

any suggestion on what gauge i could use to measure the oil system pressure, something that has a pointer that would keep the maximum pressure reached, so i could replace the pressure switch with the gauge, test run the car along a dual carriage way and then read the pressure when i get back.

Post by **billofdurham** » 26 Jan 2007, 12:16

The only way I know of testing the oil pressure relief valve is to use an oil pressure gauge. It screws into the engine block where the oil pressure sensor is located.

If you can lay hands on one the following pressures are correct for your car: 800rpm - 14psi; 4000rpm - 51psi and the pressure relief valve should open at 70psi.

One of the very few modifications I do to any car is to fit an oil pressure gauge. I do not trust oil warning lights because, by the time one comes on, you are usually painfully aware there is a problem as "the engine doesn't normally make that rattling sound."

By the way I wasn't trying to say that you had not checked and double checked everything. These were possible causes - what I usually call grabbing at straws in the wind as I had never heard of such a huge oil loss without an obvious cause.

Bill.

MisterLister · Post by **MisterLister** » 26 Jan 2007, 17:35

billofdurham wrote: By the way I wasn't trying to say that you had not checked and double checked everything. These were possible causes - what I usually call grabbing at straws in the wind as I had never heard of such a huge oil loss without an obvious cause.

Thankyou Bill for the info. i did not take it the wrong way its just the way it was typed.

I will try to get a gauge before i do any repairs to check what is going on with the oil feed then i will strip down the oil pump and relief valve; clean them up, refit and test. i will post any results i can get for those watching this thread.

MisterLister · Post by **MisterLister** » 07 Feb 2007, 02:14

i had removed my oil pump and checked it for damage and movement within the relief valve. the little plastic plunger that makes up part of the oil pressure relief was jammed it would not move.
i stripped the pump down and tried to remove the plunger it would not move, finally i had to tap it out with a hammer and pin punch.
the plunger and liner where grooved. inbedded in the plunger was a metal splinter.
i checked with my local dealer who tells me the plunger and spring are not servicable, the whole pump has to be replaced. for

Baker · Post by **Baker** » 07 Feb 2007, 10:41

If you are still interested in some oil pressure gauges go to Ashcroft.com.
These are industrial gauges (4.5 inch dials) and are probably to large and expensive but its a start. A maximum pressure memory pointer is an option.