SOS - What would you do in my case/ on the fence?

[BrianJD]

What would you do with this xc90 if it were yours? ..I recently got a 2006 XC90 2.5 T5 from my boss..for free. He said it needed a battery and alternator. I had it brought home on a flat bed tow truck and changed the alternator $280 and recharged the battery (which was brand new last year.) runs and starts good.

He bought it new but it's now got 438,000 kms on it. It came with a TON of maintenance receipts and repairs from the local Volvo dealer. In fact there's probably $25 or more spent on it since new..including a new $4k transmission (last year), new angle gear @ $1800, suspension work, 2 new cats and O2 sensors, new struts - brakes pads rotors tires, new heater fan.. and list goes on and on...BUT! I checked the compression yesterday and it's not good.
110 110 110 70 & 105 for cylinders 1 - 5. and the turbo tube has oil in it.

The DTC screen on the dash was working when I got it (I've only driven it 15 km) but has since gone scrambled. When I scrolled thru the DTC messages it showed the following codes were set:
ECM - DEM - DIM - DDM - CCM - PDM - PSD - REM - UEM and BCM - SAS & SRS ready - TCM & ICM were checking.
Last time I saw it work it said "low oil pressure - stop engine" message.

I realize water intrusion/ corrosion into the CEM under the wiper cowl could cause all of these codes (and I also had the rear hatch handle removed as well). I read/ saw that cleaning the CEM connection pins can resolve a lot of these DTC issues.
A/C has a leak and needs repair. Heater, stereo, windows, mirrors and heated seats etc all work - no rust - a few tiny dents in the body. ..will need tires.
Some of the above work was last year and some it was 5 years ago or more. There's a lot of positive things that come with it but an worn out engine is not one. The PCV valve is also good too.
What should I / would you do with it? Should I sell it for parts/ as is?
I don't have room here to pull the engine and get it rebuilt. Your opinions are welcome ..please and thanx.

[RickHaleParker]

A low Battery or noisy Alternator would trip lots of codes. Get Vida-DiCE setup, clear the DTCs, see what comes back.

[oragex]

As above. Once codes clear, see what's with the oil pressure message. Either the sensor, worn oil pump, or worse failed oil pan o-rings or clogged pick up mesh. With the actual kms, all but a sensor replacement would be a no go for me. If the oil pressure light doesn't return, I'd run it until it dies spending the least money on it - enough to keep it safe and running. With all the money already, 500K km is about the most of the usable life on these. I've seen one dead with exactly the same kms and seen on internet a few others with even more kms - but no doubt money was spent on them.

[BrianJD]

With nothing to lose, maybe I could try letting it sit for a week? with 4- 5 litres of diesel fuel in the the crank to dissolve the sludge from the oil passages, pickup/ oil pan. I could add some on top of the cylinders as well. If I crank it over once or twice every day with the spark plugs out it might loosen up the piston rings and oil passages. Do you think this would dissolve the deposits in the oil pick up without ruining the seals? or will it sound like a can full of hammers when I start it?
If that doesn't work what can I expect to sell it for$?

[SuperHerman]

The answer to your question involves how much work you want to put into the vehicle.

My concern is the oil pressure warning - it could be just the oil pan o-rings. Most of the time that is the issue. It could also be sludge which will be addressed.

First thing I would do is drain the oil and look carefully at it for any signs of metal sparkle. Also look at the condition of the oil - filthy black or normal. If you have access to a camera scope I would remove the spark plugs and look down each cylinder, turning the engine by hand to examine the cylinder walls for scouring. If you find metal in the oil or scouring of the cylinder walls you need a new engine. Why go down this path? Low compression and oil pressure warning translate many times to driving the car with no oil and ruining the pistons rings and possibly the block. If it passes this test I would proceed as follows:

1) examine oil pump area, by harmonic balancer for signs of oil leaks - could cause oil pressure problems;
2) do a glove test on the PCV system on the oil fill cap;
3) drop the oil pan clean it up and any other areas that look sludgey then replace the o-rings (this should be mostly labor and about $30 in parts - use the proper sealant (not rtv) - there are plenty of write ups on the forum about this). Make sure the square drain tube from the PCV firebox is clear of crud. At the same time look for sludge - this could be the cause of your oil pressure problems. The best way to tackle the sludge is starting with the oil pan off. If you find sludge;
4) don't seal the oil pan, just install it (with new - o-rings) and do your diesel bath, you will have leaks, but it should be okay. You need to degunk the top end. Then drop the pan again and examine what you find. If you have huge chunks keep at it. Change your oil filter at the start. When you are satisfied drop the pan, clean up as required, install o-rings and seal it correctly.
[you could skip the step and seal it immediately with new o-rings and hope for the best - removing it with the sealant is not that big a deal and resealing it is not that difficult - your call]
5) once you are happy, change the oil and filter again - use some cheap oil and run the engine and monitor very carefully for low pressure warnings - you may throw some clots. Let it run for 30 minutes or more, sitting in the car paying attention. Put some SeaFoam or equivalent in it, run for 15 or more minutes and drain and replace filter and put in quality oil. Run if a few times for 30 or so minutes (all of these are in your working space/garage). If you have no messages go ahead and drive it.
6) keep an eye on the oil pressure lights and oil condition via the dipstick. At 1k miles, check your compression and change the oil. Add 1/2 can of SeaFoam and drive it normally. Keep monitoring oil condition.

The low compression, if not from engine damage, is from sticking rings and this takes some time to work through. Don't worry about oil in the tubes for the turbo - concern is if it starts smoking. Some oil is normal - smoke is a sign the turbo may have issues.

My basic thought is the oil pressure issue is the o-rings leaking on the oil pan. Doing your diesel bath will not solve this. As the pan has to come down to address the o-rings - I would do this first. If it is really sludgey - doing your diesel oil bath would work. I would turn the engine by hand and completely fill the engine - I mean to the point the head is also in the bath. VW has a system where they pump a solvent in that does the same and there is a filter attached - the engine is basically power flushed with solvent until it is cleaned.

The 2.5T is not known for being sludgey, but poor maintenance could cause it. Dropping that oil pan will tell you a ton. So - read between the lines and adjust what I have suggested based on what you find. It could be simply drop the pan, clean the pan, install new rings and go. A weekend and $30 bucks in parts, not including oil and filter, could solve your issues. Once you clear this issue you can address the other wear items.

[RickHaleParker]

The low compression, if not from engine damage, is from sticking rings and this takes some time to work through.

Seafoam poured directly into the cylinders and left to soak overnight will eat the deposits and unstuck the rings quickly. Deep black smoke after the restart is expected. It is the carbon burning off and can take up to 45 minutes to clear.

1. Pour Seafoam directly into the cylinders.
2. Stuff rags down the spark plug wells.
3. Let sit overnight.
4. Crank engine to push out any remaining liquid Seafoam.
5. Reassemble and start engine.
6. Let idle until it stops blowing black smoke.
7. Take out for a drive, keep doing hard accelerations until it no longer blows black smoke.
8. Let engine cool and retest compression.

[BrianJD]

The answer to your question involves how much work you want to put into the vehicle.

My concern is the oil pressure warning - it could be just the oil pan o-rings. Most of the time that is the issue. It could also be sludge which will be addressed.

First thing I would do is drain the oil and look carefully at it for any signs of metal sparkle. Also look at the condition of the oil - filthy black or normal. If you have access to a camera scope I would remove the spark plugs and look down each cylinder, turning the engine by hand to examine the cylinder walls for scouring. If you find metal in the oil or scouring of the cylinder walls you need a new engine. Why go down this path? Low compression and oil pressure warning translate many times to driving the car with no oil and ruining the pistons rings and possibly the block. If it passes this test I would proceed as follows:

1) examine oil pump area, by harmonic balancer for signs of oil leaks - could cause oil pressure problems;
2) do a glove test on the PCV system on the oil fill cap;
3) drop the oil pan clean it up and any other areas that look sludgey then replace the o-rings (this should be mostly labor and about $30 in parts - use the proper sealant (not rtv) - there are plenty of write ups on the forum about this). Make sure the square drain tube from the PCV firebox is clear of crud. At the same time look for sludge - this could be the cause of your oil pressure problems. The best way to tackle the sludge is starting with the oil pan off. If you find sludge;
4) don't seal the oil pan, just install it (with new - o-rings) and do your diesel bath, you will have leaks, but it should be okay. You need to degunk the top end. Then drop the pan again and examine what you find. If you have huge chunks keep at it. Change your oil filter at the start. When you are satisfied drop the pan, clean up as required, install o-rings and seal it correctly.
[you could skip the step and seal it immediately with new o-rings and hope for the best - removing it with the sealant is not that big a deal and resealing it is not that difficult - your call]
5) once you are happy, change the oil and filter again - use some cheap oil and run the engine and monitor very carefully for low pressure warnings - you may throw some clots. Let it run for 30 minutes or more, sitting in the car paying attention. Put some SeaFoam or equivalent in it, run for 15 or more minutes and drain and replace filter and put in quality oil. Run if a few times for 30 or so minutes (all of these are in your working space/garage). If you have no messages go ahead and drive it.
6) keep an eye on the oil pressure lights and oil condition via the dipstick. At 1k miles, check your compression and change the oil. Add 1/2 can of SeaFoam and drive it normally. Keep monitoring oil condition.

The low compression, if not from engine damage, is from sticking rings and this takes some time to work through. Don't worry about oil in the tubes for the turbo - concern is if it starts smoking. Some oil is normal - smoke is a sign the turbo may have issues.

My basic thought is the oil pressure issue is the o-rings leaking on the oil pan. Doing your diesel bath will not solve this. As the pan has to come down to address the o-rings - I would do this first. If it is really sludgey - doing your diesel oil bath would work. I would turn the engine by hand and completely fill the engine - I mean to the point the head is also in the bath. VW has a system where they pump a solvent in that does the same and there is a filter attached - the engine is basically power flushed with solvent until it is cleaned.

The 2.5T is not known for being sludgey, but poor maintenance could cause it. Dropping that oil pan will tell you a ton. So - read between the lines and adjust what I have suggested based on what you find. It could be simply drop the pan, clean the pan, install new rings and go. A weekend and $30 bucks in parts, not including oil and filter, could solve your issues. Once you clear this issue you can address the other wear items.

Great advice! Thanks so much for your time on my behalf!...I drained the oil today and it looked very dirty and thick( it was room temperature)..but surprisingly had no sludge. The filter didn't look too bad either. I expected to see "chunks" but I haven't run it thru a coffee filter yet. I scoured the drain pan with a rare earth magnet and again was surprised to find no steel on it. I did not install a new filter cartridge but reinstalled the plastic outer filter cover ( which had some dirt in it) then added 4 litres of diesel fuel and 20 cc or more of diesel on top of the pistons too. I crank it over every few hours with the plugs out. I'll drain it tomorrow and see what I get. The engine has no leaks from the seals but I see the power steering pump has been leaking.
I did the glove test over the oil filler cap and and it is good. How do I de-sludge the top end if the valve cover also holds the cam shafts in place? I will do the recommended oil / Seafoam/ o rings/ drop the pan, if I don't get the low oil pressure light to go out after this 1st oil change.
Thanx again for your time..much appreciated!!!

[BrianJD]

The low compression, if not from engine damage, is from sticking rings and this takes some time to work through.

Seafoam poured directly into the cylinders and left to soak overnight will eat the deposits and unstuck the rings quickly. Deep black smoke after the restart is expected. It is the carbon burning off and can take up to 45 minutes to clear.

1. Pour Seafoam directly into the cylinders.
2. Stuff rags down the spark plug wells.
3. Let sit overnight.
4. Crank engine to push out any remaining liquid Seafoam.
5. Reassemble and start engine.
6. Let idle until it stops blowing black smoke.
7. Take out for a drive, keep doing hard accelerations until it no longer blows black smoke.
8. Let engine cool and retest compression.

Thanks to take the time to reply! Good advice .which I got from a buddy as well. I did add some Seafoam in the spark plug holes yesterday and added some diesel today. I'll drain it off / blow it out with compressed air tomorrow and do the reassemble/ idle test drive..( but it's snowing quite a bit right now and over night) so I don't know how much hard acceleration I can do tomorrow. I saw some ppl have used Engine Restore with proven good results - I have a can of it here that I got today -$20. What do think?

[SuperHerman]

It is really hard to tell how bad a sludge issue on a Volvo is b/c the cam cover is the valve cover - so there is no great way to see how the valve train looks. Removing the cam cover is major surgery. Usually from pass side to driver side, valves 1-3 are fairly clean and then they start to get dirty as one moves to 4 and 5. That is what I found on my XC70 when I did the head gasket - and the car was pretty well serviced. I am not sure if the grate comes off from above on the oil filler port. If it does you can pull it out and try looking - you can do a little looking with it on. Dropping the pan provides some clues, which is why I suggested it - plus those o-ring seals age and cause the low pressure issue.

I had a Land Rover which had sludge issues, and the shop did the head gaskets and cleaned it as best they could. Unfortunately it wasn't good enough and the engine blew a few thousand miles later with my wife driving it in the middle of no where. She said a red light turned on and kept driving it - rod through the block was the result. It must have thrown a clot, plugged some oil passage and oil starvation. That is why I recommend taking it slow as you work it out - keeping an eye on the oil color. If it gets black real fast then you know there is still sludge getting washed out. Just keep cleaning it slowly and shut it down if the oil pressure light turns on. (Again, changing the o-rings eliminates them as a potential cause and makes the process easier to handle). The 2.5T in the XC90 is a great vehicle when treated correctly. My sister had hers to 250,000 miles before the steering rack went, which spelled its end as it just wasn't worth fixing when the shop charges were added to the part cost.