V70R "No oil pressure" warning light

V70r carbon · Post by **V70r carbon** » 18 May 2018, 20:55

It's been 12k since Ive changed the head gasket (valve stem seals, planed the head, etc..etc.. and though I'm due for another oil change, I've been getting a " no oil pressure,,stop immediately" warning light flicker at idle after it's run for an hour or so.
When the head gasket blew out at a light and I smoked out traffic behind me, I got a " low oil level.. stop immediately" warning message and after pulling over the oil level was way over the top because of the coolant in the pan. Is it possible that the oil pressure sensor is the cause of the no oil pressure warning message that I'm getting now or is it worse than that?

Post by **SuperHerman** » 18 May 2018, 23:09

Based on your description it sounds like the sensor is working correctly. At idle low pressure and light flickers, hit the rpms and pressure increases and oil light turns off - this sounds like a working sensor. Possible sensor issue, doubtful but possible.

Generally on higher mileage older Volvos the problem is certain O-rings in the oil pan. The get hard and leak causing a lack of pressure. Changing these and making sure your PCV system is clear where it mates to the block usually resolves the issue. You will find write ups on doing this job - if you shop around you can find the O-ring kit for under $20. It is not a fun job, but not bad. If you do the job yourself use the proper anaerobic sealant and not RTV/Silicon. If you look at the similar topics that pop up at the bottom of your post, you will see the material you need. Read all the posts on this one:

viewtopic.php?f=9&t=59855

Yes you may have an oil pump issue, yes you may have some serious engine bearing issues if you cooked the engine during the head gasket blow out. Other possibility is you have thrown a "clot" into one of the oil passage galleries. Most likely the O-rings.

Did you do the head gasket work? If so you should be able to determine how much sludge you had, if any, and then exclude a "clot".

KurtL · Post by **KurtL** » 19 May 2018, 09:17

I had the exact same problem. After getting the o rings on the pan replaced and the pcv system serviced it went away. I also use Mobil 1 High Mileage Synthetic 10-40 oil which helped.

Post by **cn90** » 19 May 2018, 11:24

- The key thing about oil pan job is to park the car inside your garage (if you have one), drain the oil overnight.
It will be much more pleasant to do it the next morning.

Canadian Moose · Post by **Canadian Moose** » 21 May 2018, 16:36

Replace o-rings and clean all the oil passages that may be blocked. Possibly replace or clean the pick up tube. Change the oil and filter about 1000 miles after doing the o-rings as there will be sludge accumulated in the filter after cleaning the passages.

Post by **SuperHerman** » 21 May 2018, 21:12

After the pan is removed I spray carb cleaner around the inside of the engine block walls and let it drip into the pan. I do this a few times to get as much oil off as possible so that when I am about to assemble I avoid any oil runs that will ruin the anaerobic sealant. After the oil rings are installed (I like to use thick assembly lube - Vaseline will work - to make sure the o rings stay in place), I apply the sealant on the pan which has been cleaned and wiped with brake fluid rag, wipe down the inside walls and mating surface with a cloth, then the block mating surface with brake cleaner and make sure it is clean. Final check for oil drip - if any go at it again - then with a helper (after checking the O-rings one last time) I put the pan on and tighten up. You need a helper to hold the pan in place or you can rig a rolling jack as you tighten the first four corners.