Oil pressure problems

MilesM · Post by **MilesM** » 07 Apr 2019, 19:35

My 2002 V70 non-turbo has The dreaded “no oil pressure, stop engine” error message. This car was certainly neglected before I got it. There was a lot of sludge in the bottom of the pan when I dropped it to replace the O-rings. Now, however, I’m still getting the oil pressure message.

I decided to use a can of liquid Molly engine flush to try and clean out all the oil passages. I ran that through, then dropped the pan again a second time and also replaced the O-ring on the oil pick up tube which I didn’t get the first time around.

No, from cold, I can run for about 20 or 25 minutes before I start getting the oil pressure light. If I pull over and listen to the motor, there isn’t any valve noise or anything like that indicating that there is any oil starvation at the top end of the engine. I do have a bit of a leak somewhere around the VVT solenoid though. It could be the cam seal, although the oil seems to be accumulating on top of the head just behind the VVT solenoid.

Any thoughts on what to fix next to get rid of this problem?

Thanks,

Miles

Post by **RickHaleParker** » 07 Apr 2019, 20:04

Have you considered, the Oil pressure sensor might be a liar or plugged up with sludge?

MilesM · Post by **MilesM** » 08 Apr 2019, 01:09

I wondered about the oil pressure sender way back before I dropped the pan to install the new oil rings, so I swapped one in from a scrap car and I still get the same error. It could still be sludge plugging the sender, but I did clean it out before installing. I bought a cheap manual oil pressure gauge a while back, but the kit didn't have a fitting the right size for the car (of course I never think of it when I'm in a store that might have one...).

I've been thinking maybe electrical; has anyone have wiring for the oil sender go bad?

Would a leaking cam seal have this sort of effect causing an oil pressure drop?

Thanks,

Miles

Post by **abscate** » 08 Apr 2019, 03:43

Pressure test ITV with a known gauge. If the car ran with lots of sludge, the oil pump could be worn out and will need replacing. Not too bad a job on Volvo. It lives behind the harmonic balancer on the crankshaft

Post by **jimmy57** » 08 Apr 2019, 08:05

Leaking cam seal or leak at CVVT solenoid will not cause this. If the gasket under CVVT was dumping the supply oil to the return hole then check engine light would be on.
Did the O ring on the tube to the oil filter housing get changed? The pipe with the one bolt holding it to the housing the oil filter sticks up into?

MilesM · Post by **MilesM** » 08 Apr 2019, 16:38

I'm looking at the price for a new oil pump - can these be rebuilt or new seals installed instead of being replaced?

@abscate Yes, I replaced all the o-rings and seals (plus the one for the oil pickup tube) as per instructions here: Volvo oil sump o ring replacement

@jimmy57 I'm not throwing a check engine light, so I'm thinking more and more it's the cam seal. I didn't think it would be enough to cause the low pressure error, but I'm glad to have it confirmed by other Volvo experts. I'm pretty sure it's the exhaust cam so at least that makes the job a bit easier on a non-turbo engine (no VVT on exhaust).

Does anyone know off-hand what size thread the oil pressure sender uses? I need to get a fitting for my pressure gauge so I can actually read the pressures...

Thanks,
M.

tardcart · Post by **tardcart** » 08 Apr 2019, 17:34

the sender is wishful thinking. its not the cam seals. Your last shot before switching engines is the pump, but you probably already have a hunch its the bearings. If you just want to use the car for several years put 20/50 wt or straight 30 lawn mower oil in. It might out live you.

Post by **jimmy57** » 08 Apr 2019, 17:49

If you have an old oil pressure switch you can knock the head off and drill and tap it for the 1/8 NPT fitting that are universal with oil pressure gauges. The thread size is 14x1.5 but it seals with a washer.

The oil pump is not rebuildable as there is no service kit, you replace it. Oil pumps are rarely the cause. If there is any oil in engine the the pump is lubed. Some engines have pumps that are problematic (Buick V6 and V8 for one) but these pumps are not usually it. If the relief has something stuck in it where it is dumping some of the pump output then that can be removed by disassembling pump. The adapter at bottom of the photo is the Volvo adapter shown in the oil pressure gauge kit.

Post by **jimmy57** » 08 Apr 2019, 17:57

I do agree with Tardcart, one of the mains can get wiped out and you will not have any noises but it will loose enough oil to drop the pressure under 9 psi idling. It is worth looking at pump and when you separate the two halves the relief valve is the bullet with the spring behind it down in a hole. If you remove the bullet and find something there like o ring bits or a big chunk of the sludge coal then you are in luck.

MilesM · Post by **MilesM** » 09 Apr 2019, 11:41

I hadn't thought of tapping an old sensor, good idea. I'll give that a go on the weekend and I'll have a better idea of what I'm actually working with...

I certainly hope that it's not the bearings, but I might just have to face the facts and start looking for a long block.