2000 C70 Oil light stays on

Joppadad · Post by **Joppadad** » 29 Mar 2014, 20:53

At 77,000 miles the turbo went, shaft separated, Flame trap was clogged, car had it's own smoke screen. I replaced the flame trap, and the turbo, pulled oil sump, cleaned, replaced seals with Victor Reinz kit and flushed oil with cleaner; changed filter and oil. Replaced oil pressure switch when sump was off as it was much easier to get to. The anti freeze was clear and the oil had no milky tint to it so I assume that the excess pressure from the faulty flame trap did not affect the head gasket. After putting it all back together the oil light was out on startup and while idling for about three minutes but when I took it out on the road it came back on. I will add that there is no noise ( lifter tap, squeeling, etc.) Can a oil cap gasket cause the light to come on? I plan to buy a oil pressure test kit; what should the pressure for the 2.4L be?

Post by **rspi** » 29 Mar 2014, 22:28

I will step out there and say no on the oil cap gasket.

Post by **abscate** » 30 Mar 2014, 06:50

All data reports at 4000 rpm minimum oil pressure of 0.35 MPa is spec.

At 800 rpm, 0.10 MPa is spec

All pressure are with oil at 100C, or after 15Minutes driving.

I'll need another cup of coffee to convert but 1 MPa is 10 bar or 140 psi.

Your sender is supposed to close at low oil pressure of between 5.6 and 8.3 psi, check that first!

Joppadad · Post by **Joppadad** » 30 Mar 2014, 13:55

Thanks Abscate, so your saying that at idle the pressure should be 14 psi? I replaced sensor, although new does not necessarily equate to working properly. I don't believe it would be advisable to drive it for fifteen minutes with the oil light on. According to the VADIS conversion utility .35Mpa is 50.76 PSI. I had read in a tutorial for Oil sump cleaning that the oil cap gasket could cause loss of pressure, but that seemed unlikely to me. Is it possible to change the gaskets in the oil pump, rather than replace it?

Post by **abscate** » 30 Mar 2014, 14:10

I think once you got through the trouble of getting the oil pump out, you would replace it. It lives inboard of the harmonic balancer on these cars, so it's a timing belt removal job.

Idle pressure above 14 psi, correct

Post by **precopster** » 30 Mar 2014, 14:32

Why did you replace the oil pressure switch? Was it tested faulty?

If you still have the old one perhaps place it back on to see if the new switch is out of range......costs nothing

Joppadad · Post by **Joppadad** » 30 Mar 2014, 17:46

@ Abscate I said I removed the Oil Sump and replaced all the O rings after I cleaned it out. @precopster I replaced the oil pressure switch as the engine was making no noise that would have indicated starved lifters/etc. and when I removed it it was caked with sludge like all the other surfaces in the Oil Sump/Pan so for $12 I replaced it.
I guess the moral of the story is change the oil often, and when the oil light comes on check the oil pressure. I purchased a gauge and hooked it up this afternoon, following the procedure laid out in VADIS. I had more than enough pressure at idle; 22 over the stated 14 PSI, but it all went down hill after that. At 3000rpm the gauge had dropped to 16psi and showed no signs of climbing to the 50psi it should have at 4000rpm which mirrored the behavior of the pressure light. The oil gauge would have helped in the diagnosis, but the chain reaction pointed fingers at several culprits. However, I think the timeline went like this, flame trap plugs up and increases crankcase pressure which dislodges seals in the oil pump, starving the turbo causing it's impeller shaft to break destroying the bearings and pouring oil out the exhaust pipe. So I have replaced the flame trap, flushed the oil system, replaced the turbo which was several stages beyond a rebuild, removed the Sump and cleaned it,and verified that the pump is shot. For the sake of continuity I'll report back after I replace the Oil Pump.

Joppadad · Post by **Joppadad** » 18 Jun 2014, 19:31

alright replaced the oil pump...I haven't attached the oil pressure gauge but the car will run fine for about a mile or so and the light comes back on..I guess the next step is to pull the pan and head and do some internal cleaning.

traxcavator · Post by **traxcavator** » 16 Nov 2014, 13:18

I'm having a similar problem with a car I bought. I've changed the o-rings and cleaned out the oil pan. Now it goes about 6 miles, and then the oil pressure light comes on. Let it sit for a while, and it will go a few more miles and then turn the light on. Swapped the pressure switch which confirmed that the oil pressure really was dropping.

What I've found is that the oil filter housing has large amounts of sludge in it after only a few miles. I believe the engine (history largely unknown) was very poorly maintained so lots of sludge was created. When I replaced the head gasket, did the pan and o-rings, and then filled it with clean oil, it started washing the sludge from everywhere it had collected.

My plan is to keep replacing the oil filter every time the light comes on until it stops coming on. (Replacing the filter by the side of the road isn't that big a deal.) Then I'll change the oil every few thousand.

Getting a good look in the filter housing, and observing how much sludge is in the bottom of the housing, and how much is caught between the pleats of the filter can tell a lot. If there is a problem, it's a good idea to clean the housing very thoroughly at each filter/oil change.
John

Post by **abscate** » 16 Nov 2014, 16:58

I successfully desludged a turbo Beetle 1.8 liter using Bells automotive group desludger for about 4 oil changes in a row.