Am trying to get to the bottom of a diagnostic mystery on my 2000 V70XC wagon (70k miles) (and keep from getting further fleeced by the dealership.) We have an oil pressure light going on and off. Dealer says we have a dirty engine and low oil pressure and need a new engine. Our regular mechanic says the engine is clean, this wouldn't cause an oil pressure problem anyway, and the problem is probably electrical. We bought the car with 50K miles and have maintained it religiously. Car runs fine and sounds normal. So far we have only authorized the cleaning of the oil pan and I have serious doubts about whether we really have an oil pressure problem. Will be talking with the mechanic at the dealership tomorrow and need more information:

1. I do not have the specs for the car at hand, but I need to know what a normal oil pressure reading is for this car and what is considered a low oil pressure reading.
2. Is it proper diagnostic procedure for a Volvo dealership to conclude that a car has low oil pressure based upon the sound of the engine when they have never worked on the car before (both our regular mechanic and we think the car sounds fine) and because there is oil buildup on the oil filler cap of the engine? At least two other mechanics have told us that such buildup is normal and is not indicative of a dirty engine.
3. Is it proper diagnostic procedure to first determine that a problem is NOT electrical, before doing mechanical fixes? Although we asked the dealership to check whether the oil pressure light is on due to the switch, they didn't do that because "of the sound of the engine." That sounds fishy to me.
4. Is "cleaning and resealing" the oil pan an appropriate fix for an oil pressure problem and is 500 a fair price? I have no idea what, if anything, was done to the oil pump or oil pump strainer when the pan was off.
5. How much is a fair price to replace the oil pressure sending unit on this car, broken down by parts and labor?
6. I'd like to have a diagram of the engine, the sending switch and the oil pump in front of me when I talk to the mechanic. Is there a site where I can download this information.

THANKS!!!!

 

Did your other mechanic tell you there was low pressure or was it just the dealership? If your guy said it isn't low, I would go to a different dealer. A new oil pan for that car is 400. Cleaning and gasket for 500? Hmmm.

 

I may be a litte off on the pressure. Idle 750Rpm .10Mpa about 30 or 40 Psi 4000Rpm .35Mpa about 50 Psi.

Was the engine tapping at all?
What oil pressure reading did you get?

Was all the oil pan o-rings replaced?

 

thanks very, very much. Will let you know how it turns out. This is a great resource, by the way!

 

I have a question about oil pressure message on the display of my '01 v70xc. I read a lot about this problem on this forum and decided to replace "o rings" since everybody was pointing in that direction first.
Well, I installed new o-rings today and I still have the "no oil pressure-stop the engine" message and oil light on. It comes and goes, sometimes it's on with low rpm, sometimes it comes in at 3000 rpm's. Doesnt make much sense. Engine runs fine, quiet. When oil pan was down everything looked fine, there was no metal residue in the pan. Rings were not bad, little pressed but not too bad.
So, what would you guys suggest to be done next? I should have replaced oil pressure switch first, I regret that now. Where is it located on cross country anyway? I see eeuroparts is selling it for $10 and it's same part for majority of volvos.
What about oil pump? How hard to replace and how often it turns out being the reason for oil pressure loss on these cars?

 

Before I would spend too much money trying to fix it, I'd want to verify the sender and gage are accurate. On the older Volvo's I've had it was quite simple to add a tee to the port in the block so that the original sensor worked and then add a mechanical gage to verify the readings. I have these things laying around in my garage so it's not big deal and would think most garages would be similarily equiped to do this, or I'm sure you could do this yourself.

Jerry