2004 V70 2.5T, 196K miles. This is my son's car that has ben parked in my yard for two years. His Toyota recently died from lack of oil so he is flying in to drive this car 1,700 miles cross country. He had an oil change less than 1,000 miles before parking the car here, and it was having intermittent stalling problems in wet weather. He believed it to be from the computer connections getting corroded which when he cleaned them would resolve the stalling problem but it would come back. In prep for his cross country drive I changed the dead nine year old battery and filled the tires with air. Today I took it to Valvoline (half hour drive one way) to have the oil changed and fluids checked. About 2 miles before I got there the oil light came on with a message that said "no oil pressure stop safety" I was at a red light when I noticed the light. I pulled over and checked the oil, it was full and very clean on the stick. I happened to have my code reader and checked codes the only code was P0027. I restarted the still warm car and drove to Valvoline, they changed the oil (vacuumed - did not drain) and filter and checked all fluids. They said all fluids looked good and remarked at how clean the oil was. When I restarted the car the oil light was off but the check engine light was on, I drive 1/2 miles to the Grocery store and letting the car idle while I checked the codes got P0027 and a code about an evaporative system leak. I cleared the codes and went inside to do some shopping (abt 20 min) came back out and the car started with no problems, no CEL or oil light. Drive 2 miles to Wal-Mart (shopped for about 40 minutes) and again the car started with no problems. Both times starting the car after shopping the temp gage was between 1/4 to 1/2. When normal driving/idling the temp gage is at 1/2. While ideling and checking codes the temp gage was at 1/2 and my code reader reported the temp at 200. The 1/2 hour drive home was uneventful (the last 10 minutes has a 8% grade from 750 ft to 1850 feet - which the car made easily) as I pulled into my driveway I noticed the oil light was on and when I parked the car the message center said "no oil pressure - turn engine off". I turned the engine off and then turned the key to on so I could check codes there were no codes. I immediately restarted the car and let it idle for about 5 minutes the oil light did not come back on. There are no volvo techs (or even euro techs) in my area. My son is wondering if this could be related to the computer contacts being corroded? Regardless, we will be trying to resolve this on my gravel driveway before he drives 1,700 miles cross country.
Has anyone had this SAME issue (oil light comming on after driving and then "resetting" when turning the car off and back on) and what was the remedy? Or, where should we be looking first to resolve this?

 

If you get a "reset" by turning the car on and off, then that suggests there's a wonky relay somewhere. I'd start by checking system voltage after a restart and again after the light comes on. If that's normal you can rule out the voltage regulator (which has relays) and then consider it may be the CEM or a stand alone relay. For CEM diagostics, check out the XeModex web site. The only other thing about oil pressure is whether you trust the sensor or not A shop may be able to put a manual guage on it temporarliy to do some diagnostics or even throw a new sensor at it - worst case is you have some debris in the oil pick up or weak o rings on the pump that will diminishs the oil pressure. Best way to check is to drop the oil pan and inspect for bits in the oil and check if the pick up is clean.

 

What is normal?

 

A common cause of low oil pressure is a build up of "sludge" in the oil pan. A charcoal like substance forms in the engine and partially clogs the oil pick up tube. With 200k on the engine - I'd bet the PCV system is clogged and the oil pan is full of sludge.
Keep in mind the turbo is fragile - and very susceptible to low oil pressure. (which you have had for a while)

What would I do before driving across country in a 22 year old 200k Volvo? To be honest I wouldn't, if i had to I would ship the car. But some items to consider for starters -

When was the PCV system changed? if not recently do it now. You will need to remove the oil pan to be able to clean the oil drain in the block for the PCV system. At that point you will find an oil pan full of crud and an oil pickup tube that will need to be changed to the new style "tulip" shaped pickup. (that is less likely to become clogged. )

If the PCV system is clogged even partially - you will find the car broken down on the side on the expressway when the uncontrolled internal pressures from blowby have pushed the front cam seals out and dumped all your oil onto the cam belt and front of the engine. If lucky you will catch this before the timing belt comes off and totals the car.

When was the timing belt changed? When was the transmission oil changed? (with the correct fluid) Does the ac compressor still work when it gets hot? How old is the alternator? When was the radiator and water pump replaced? (if it's AWD has the angle gear fluid been checked or changed?)

These are all items I have seen fail many times on customers cars when they get many miles on them.

 

Update
Thursday (April 16th) I changed out the oil pressure sensor and took the car for an hour long drive simulating all the same conditions that had given me the oik light previously, the light did not come on and the temp never rose above 194 degrees. After doing some errands I drive the car home and when I started up the mountain (8% grade, 1,1000 foot climb up a twisting road) drove it HARD! (I alowed a 300Z with racing wing to pass me and stayed on his tail all the way up-driving 50-60 mph. Most ppl drive 35-45 up that stretch.) About halfway up the temp rose to 200 as I was nearing the top the temp was 215. Just as I crested the top the oil light came on. I pulled over and turned the car off and restarted the light was off but the temp was still at 215. I only drove about 100 feet and the light came back on. I then turn the car off and let it sit till the temp dropped to 200. I restarted the car and drove the last 2 miles home (@ 55 mph with rolling hills) the light did not come back on the car ran well and the temp dropped back down to 194.
We picked up my son from the Airport Friday night and Saturday we dropped the oil pan. The oil that drained out (less than 250 miles) looked good with no grit or burnt odor. However, when we dropped the pan there was some slight milky streaks and alot of carbon grit in the bottom of the pan and packing passages and the oil pickup screen. We throughly cleaned and recleaned the oil pan and pickup in a degreaser tank, with a power washer, air compressor, and car cleaner. We were abke to get a new gasket set Sunday (but not a new pickup) and get it back together. My son drove the 1,700 miles through the Wyoming and Utah Rockies Monday and Tuesday with no issues. He reported that the car ran well and the oil looked good at every stop. time will tell how long the car lasts.

P.S. The AC is working great there are no codes.

 

This doesn’t sound like a computer or connector issue. The pattern points to a real intermittent oil pressure problem when the engine is hot, likely from engine wear, a restricted oil pickup, or possibly a bad oil pressure sensor. The P0027 code also fits with unstable oil pressure affecting VVT operation. A mechanical oil pressure test should be done before any long trip.