850 oil pressure issues, no oil in valvetrain

GregO · Post by **GregO** » 12 Dec 2005, 15:57

Recently changed oil and filter on my non-turbo 850, using Castrol 10-40 and OEM oil filter. Several days later, my oil light came on, stayed for a minute or so, went out. Now it comes on on every startup, goes off after a minute or so. I looked into oil filler cap, no oil in valvetrain, but dipstick shows full. Haven't driven it, just trying to figure out the possible problem. I've read a little about a plastic relief valve in the oil pump, but that's about all I can find that may lead to the problem. Any other ideas? It's almost time for a timing belt, so should I plan on perhaps an oil pump as well? Any help is greatly appreciated.
Thanks, Greg

Guest · Post by **Guest** » 12 Dec 2005, 18:24

Update: Just following up on a couple of suggestions regarding my oil pressure/no oil in valvetrain issue. Started the car, oil light went out normally. I took off the filler cap while engine was idling, and there was oil in the valvetrain this time. Earlier when I did this, the valves were dry as a bone. What could be giving intermittent oil pressure like this? I am totally baffled. Anyone have experience with this problem, or suggestions for causees? Help!

Post by **matthew1** » 12 Dec 2005, 22:39

Upstairs in my brain I have a bunch of cobwebs. In between two cobwebs in a certain dusty corner lies a bit of info that seems it may relate to this problem: clogged oil (sump?) line, where it draws from the oil reservior. Might be an o-ring. Sorry, I don't know the technical term, have never seen one, and have never gotten down there on my 850 or any car actually. Maybe someone who actually knows about this problem can chime in.

BTW, my cobwebs are not confusing this with the turbo oil return line, which is a very accessible, easy repair, but has entirely different symptoms.

saltydog · Post by **saltydog** » 13 Dec 2005, 05:55

anybody who has been watching this forum of late is familiar with my whining about my 2001 xc70 with no oil pressure, but having dealt with this for well over a year now, I consider myself somewhat of an expert on this issue. First, it seems too good to be true (& usually is) but replace the sending unit. It's the cheapest fix, & these things are suseptable to small hunks of sludge that can be stirred up when removing thigs like the drain pleg, filter, etc. It's a simple & inexpensive experiment that everyone will suggest you do first. Next is the oil pump pick-up. There is a gasket where the pick-up tube meets with the block (inside the pan obviously) that cracks & allows the pressure to drop, particularly at idle. This was common to the old B21/22 motors in the 200/700 series & the tradition continues in the 800 & recently a tech bullitin on the current model. Volvo makes a complete pick-up gasket update kit that I believe sells for 30 bucks (Canadian). Oil pump on these things are almost burn out proof - I've replaced mine & it made a small difference, but not worth the investment. When you pull the sending unit, try a manual pressure test. I spoke with Volvo's tech representative lately, & he hinted that these things don't do well with synthetic oil, which I find rather strange. He felt that going back to mineral oil will improve the flow through the engine. Have yet to switch back - will advise. The 2.4 only runs at 9 psi at idle warm. If you have more than that (& most do) YOU"VE GOT SLUDGE! That flame trap (should call it the flame booby trap) is probably plugged solid. Pull your dipstick when the car is warm & running & if you see oil smoke coming out of the tube, you're systems plugged & you could very well have what I've got - plugged oil galleys to the head. The cure for that is to boil your motor - rebuild. My experience with EVERY known internal engine cleaning process, mechanical or chemical, is that once the sludge takes hold, you're finished. In case you're wondering, my wife still drives the car, I purchased a platinum CAA membership & told her to ignore the light until the car stops running....so far, still ok, no additional smoke or blown turbo seals or anything like that, so I'm starting to think that this may not be as fatal as one might think.....we'll see. Good luck & let us know the outcome.

Guest · Post by **Guest** » 13 Dec 2005, 09:47

Thanks to Mathew1 (great site by the way, thanks) and Saltydog for the info. I've owned this car for about four months, and there has not been any issue, including a trip from Salt Lake to Las Vegas and back, until I changed the oil and filter. Any chance at all that I could've been supplied the wrong oil filter and there's a problem with flow there? I know that may be a naive question, but I gotta ask since the time frame seems to coincide. It seems that about every third time I start the car, the oil flows to the valvetrain, other times it doesn't and light stays on. Going back to Saltydog's advice, could this be anything related to the sender? Logically, it seems to be more like the sludge or O-ring clogging issues, and maybe sometimes there is a problem and sometimes not. It always seems to clear eventually, but man, I hate to drive it with that light glaring at me.
Can you guys tell me where the sender is located, and what may be the best recommendation for cleaning the passageways-short of having the engine torn down. I gotta try it, right? I have only a Haynes manual - not much help, and am an hour's drive from Salt Lake, a good shop or even a Bentley manual! Thanks for listening.
Greg

Post by **robert213** » 13 Dec 2005, 10:35

A mechanical gauge will tell you whether there is a problem is oil pressure or a faulty oil sending unit. But, from all indication, it looks like you do have an oil pressure problem.

Do more research on PVC/Flame trap/ or whaterever it is called -- clean and replace whatever necessary.

I wouldn't drive the car, until I pulled the oil pan and did a visual check of oil pump and pick-up tube.

With limited knowledge of your vehicle, my wager is on a damaged o-ring around oil pick-up tube or clogged pick-up screen.

saltydog · Post by **saltydog** » 13 Dec 2005, 11:27

one thing I didn't mention because it doesn't relate to my car, is that the factory oil filter for the 850's (non-canister type) has a check valve to prevent oil back flow to the pan. Aftermarket filters either don't have the valve or they have one that don't work too swell. Get a factory original (although I think they're made by Hastings) & try that - you may find that cures your problem.

GregO · Post by **GregO** » 19 Dec 2005, 19:22

Thanks for all of the terrific advice on this problem. I've started the engine six times since my last post, and three out of the six, the oil light goes out normally, I see oil building in the valvetrain when I remove the filler cap. I wait all day or overnight until the oil drains down between starts, and then the other times, there is no oil coming into the valvetrain, and the light stays on, valves are understandably noisy etc.
Is this common with the O-ring at the pickup tube, or with sludge issues, or incorrect filter anti drain valve? I removed the flame trap, which was much cleaner than I expected based on the threads about it.
I am getting worked up to remove the oil pan (is it as straightforward as it looks?), unless these symptoms signify a bad oil pump or something. That's a bigger job than I can tackle, I'm afraid. Anyone else ever had these symptoms, or have other ideas? Is there any recommended product or process to diagnose or possibly remedy this oil pressure inconsistency?
On the positive side, I have found three different vacuum hoses with splits or other issues. It may not have oil pressure, but it's got vacuum now!
Thanks for the help!
Greg

saltydog · Post by **saltydog** » 20 Dec 2005, 04:53

dropping the pan's as easy as it looks if you can get underneath the car.....just make sure you grab the Volvo gasket sealer - find that stuff works well. the pick up & tube seal job is pretty basic, but slow & easy is the way, don't want to do it twice. as long as you've got the right oil filter on there, my money would be on this curing your problem.

GregO · Post by **GregO** » 20 Dec 2005, 08:01

Thanks Saltydog, that's what I was kind of hoping to hear. I know that's what was more or less said in earlier replies to my questions, but thought I would see if anyone had other ideas before I went that route. I think I'll get a new oil filter, just in case mine (which was from the dealer) is faulty or has sludge or whatever. Is there an actual gasket for the pan, or is it just sealer? I've read about the pan coming off in sections, so do I remove just the lower section? Anything else I should take care of while I'm in there? Anything to look for, relatd to this job or others? Thanks for leading the blind!
Greg