The long story - I bought my 02 XC70 used a few months ago. I got a great price on it with 130,000 miles so I knew there would be some issues. Notably, it was leaking oil and the instrument cluster didn't work. But it started right up after sitting a year and drove like a champ. I added fuel and oil and drove it home.
When I arrived at home and let it sit in my driveway, I realized that the oil leak was significant [front and rear Cam Seals]. So I took it into the local shop (not a Volvo shop) to have the Cam Seals replaced along with the Water Pump, Timing Belt, and Spark Plugs. Plus Lube (non-synthetic oil) and Filter of course. Discovered crack in washer fluid reservoir too.
Drove it for a few days and realized that not having an Instrument Cluster was not going to work for me personally. So I ordered a pair of used Clusters off ebay and was going to try to solder them myself, but surprisingly one worked so I just upgraded the LEDs and popped it in. I gained 50,000 odometer miles in that fix, but you can't win them all.
Once I had a functioning cluster I realized that I had some warning messages waiting for me. Airbag, Adjust Bulb, Alarm, Fill Washer Fluid. All of these were common that I'd seen in forum posts or had known causes and solutions. However after driving a few miles the 'Oil Lamp Icon' and 'No Oil Pressure Stop Safely' message came on. I immediately stopped and checked my oil level. Then decided to drive it home and call my mechanic. He made me an appointment and after describing that there wasn't any sign of no oil pressure other than the light told me it was possibly a sensor that was out, that they didn't catch since the cluster didn't work when it left the shop. He suggested I keep a keen eye and ear out for signs of no oil pressure, but told me it could be driven if I wanted to. My appointment wasn't for a few weeks so I drove it to work a few miles a day. I ordered a new oil cap seal just to rule out that possibility. A few days before my appointment I was bored and decided to drive my car 20 minutes up into the hills for fun. I drove up to the top of a dirt road and was so impressed by the handling and ability of this car. When I reached the top of the hill I noticed white smoke coming out of my tailpipe. I thought it might be from the cooler temperature meeting the heat of the exhaust. I drove back home and noticed the smoke trailing behind me all the way back. By the time I reached my house I was fearing that I blew out the main seal with the amount of smoke pouring out. I looked into the symptoms and the oil level seemed at the top looking like honey, my coolant reservoir was dry, and there appeared to be no mixing in the oil. I determined that it must be the Turbocharger failing. Took it into the mechanic and he confirmed that the Turbo did fail, and according to his measurements I was down a quart of oil too.
Got a used Turbocharger installed and he replaced the Oil Pressure Sensor as he originally planned. The warning message was gone and my car was running like a champ again. I decided to drive it at highway speed to a nearby town 30 miles away to get a feel for it. When I arrived in the town the 'No Oil Pressure Stop Safely' light had returned, but was coming on and going off intermittently. I stopped and checked my oil and engine, it was all good, levels good. What could be causing this message? I haven't had any leaking oil since the Cam Seals were replaced. Is there another common cause for this warning? It is a terrifying message to have to ignore. Experts please bring some knowledge and experience to this concern.

 

two thoughts - it can be the sensor (ie wiring or the sensor itself) or you actually have low oil pressure. Causes of low oil pressure can include wrong engine oil weight, an after market oil filter that's too restrictive, debris or gunk in the oil pick up, failing oil pump.

you are correct to not ignore the warning. Stop driving the car immediately and have a shop properly diagnose the cause. They would likely need to drop the oil pan if they can't find a fault with the sensor/circuit or if they in fact measure low pressure via a tool like VIDA-DICE.

 

Called the mechanic to verify that they had checked the pressure [they had]. I also confirmed the oil type used was SAE5/30. I will bring it in Monday or Tuesday so they can have another look. The light was sort of flickering on and off last night when I drove it out of town (60 miles roundtrip - message came on at 30 miles driving 60 mph). This morning I drove it up the hill for about 15 minutes and it came back on solid until I was back home. I drove it into town a few times (less than 5 miles round trip), and no light came on. It almost seems like I could drive it in town for shorter trips without ever seeing this message. Unfortunately that does not meet my expectations for this vehicle. I'll keep posting as this continues.

 

the pressure test should be done on a test drive to see if it fluctuates with load/engine speed/road speed. You have some oil pressure - since your light goes out. The question is what makes the light go on... Still could be debris in the pick up etc so the only way to be certain would be to either find the cause an errant signal or do some data logging via a smart OBD2 device to see what's going on when when the light flickers.. I had an intermittant oil light on my VW CC and the dealer was only able to reproduce during a test drive while logging data. They dropped the pan and there was debris in the pick up. (got a new long block under warranty as part of the repair since the car only had 48K miles at the time).

 

I agree with you. I didn't mention it in the original post, but previously the oil light was coming on after about five minutes of driving or even idling. So I think the Sensor did fix that problem. The mechanic has a solid reputation around here. My guess is that we are going to end up dropping the Oil Pan and cleaning out some debris. The fact that the Turbo went out, and the overall lack of maintenance by the previous owner seems to point in that direction. If I go that route I'll ask for some pictures for the forum.

 

cool, good point about the turbo failure possibly throwing something that has gotten to the oil pickup. Good sense to drop the pan and have them clean out any gunk as well - even if its just for peace of mind. post up how you make out.

 

I would not dismiss the oil problem as a sending unit. The only way to deal with this for sure is to drop the oil pan and pickup tube. Often on a vehicle of this age, the two O-rings that seal the pan's pickup port to the oil pump have begun to disintegrate along with the seal for the oil pickup tube. This fault allows air to be drawn in and lowering the oil pressure.

While you do the job, have the pan and oil separator drain cleaned in a jet wash at a machine shop. Have the oil pickup tube cleaned that way too.

I wrote a thread recently about cleaning the drain channel in the pan. You also need to replace the entire PCV box when you do this job along with the associated hoses.

 

yep Tony, I think that post is worthy of a sticky. I need to figure out if I can do that as a mod.

 

https://volvoforums.com/forum/volvo-...service-96198/

 

So I heard back from the mechanic today. They attached an analog oil pressure gauge up to the engine and confirmed that after a certain amount of time driving the oil pressure does in fact drop to zero. His suggestion was to replace the Oil Pump. He thought that with the miles on the engine, crossed with the likelihood that the previous owners drove many miles with no pressure [while the instrument cluster was non-functional], that replacing the engine might be a more favorable long term solution for me. Furthermore he's backed up for weeks, so I may have to tow it to the Volvo guy in Spokane [45 miles]. He was skeptical of my debris clogged Oil Pan Pick Up Screen suggestion due to the zero pressure reading, and agreed that that may only fix my peace of mind. I'm heartbroken and mulling over my options through the weekend. I need a solid commuter/daily driver, so I may have to let this one go. Tempting to roll the dice and toss in a used engine. I do love this car... However, I am approaching my budget on this project already.

 

This could end up being a simple fix. Someone has to drop the oil pan and look inside. I would not replace the oil pump. I would start with removing the pan and pickup tube, then installing new O-rings and clean up what you have.