98V70 na volvo - appears to have died

[mrbrian200]

Run your can opener through the dishwasher. I do it all the time. You might be scared about traces of cadmium in your chicken soup. For me, the thought that traces of spicy refried beans might fall into my cherry pie filling is just super gross. In the dishwasher you go!

[98v70dad]

I don't want traces of cadmium and other heavy metals in my campbell's soup.

Can't be any worst the then the chemicals Campbell puts in, besides it will wash off.

Good luck with the Tin Snips, I think you can better control the forces with a Hacksaw.

Got any buddies with an Engine Lathe? Clamp the filter in the jaw and cut the jacket at low RPM.

$40.00 for a oil filter cutter is out of the question for a one shot.

Thanks. Actually cadmium is extremely toxic. I've been exposed to enough of that, chromium and other nasty stuff at work over the last 40 years to make it worth my while to avoid it. You're right about the tin snips - My filter was a Mann (not Mahle like I said previously). The Mann is an extremely robust filter. There was no way snips were going to cut into it. I ended up carefully draining the filter and cutting it off with a diamond encrusted cutting wheel in my dremel. I bought it cheap at Harbor freight years ago for a one use project and it came in handy tonight. It worked well.

So after the concern about making a mess, the pan I carefully contained the oil in fell off my workbench and poured its contents into a bucket of wood scraps - what a mess. It took me longer to clean that up than dissecting the oil filter.

So, here' the result of the oil filter autopsy.

1) the bypass valve was functional
2) the flowback valve was functional
3) there was no evidence of sludge or being clogged with crud
4) the oil on the dirty side was a little gritty - it felt a little like GOJO but with a much finer grit. This surprised me a bit but that's what filters do - the oil drained from the car is as smooth as fresh oil - so the filter was doing its job.
5) I looked for color in the pan - found none
5) I looked for more metal pieces of a substantial size. I found 2 or three hunks about the size of a BB. They look like chewed up aluminum. Initially I thought they were slightly attracted to a magnet but when I got them patted dry they didn't attract. I'll try tomorrow after everything has dried a bit more

In short I found nothing too surprising and nothing that will help me figure out what happened. I put all of the parts in a zip lock bag in case I think of something else to look for.

[cn90]

- Interesting that these are Aluminum bits and pieces.

- If someone has a spare oil pump lying around, please check the impeller of the oil pump. I think the oil pump impeller is always steel, but someone can check for us that it is steel and not aluminum.

[mrbrian200]

There are pictures of the insides of these oil pumps. Here...
Credit: https://www.matthewsvolvosite.com/forums/vie ... hp?t=69826

Maybe not the exact PN however it is likely the materials would be consistent within the engine family between '98-'99.
These are a type of gear pump, not a centrifugal impeller/vane design. The center driven gear looks like a carbon steel.
The outer ring gear, I believe called the crescent, looks like some sort of aluminum alloy, as does the outer case/casting.
Aluminum bits would most likely be from the outer ring if it is aluminum, as it would be a softer metal.

[RickHaleParker]

Gerotor pump.
On the inlet side the space between the teeth is expanding.
On the outlet side the space between the teeth is contracting.





I believe called the crescent

Referring to the picture in the most previous post....
If the crescent at the bottom between the gear teeth where to get sheared across the face of the crescent. Pumping action would be lost because oil could freely backflow to the inlet side, also thin crescent shaped fragments would be spit out the outlet. A defective damper might create enough vibration to make it happen.

Then there is the sound a defective damper would cause ......

Do not start the engine up again, the timing belt is right behind the damper and on the same shaft ....

I don't think he needs to drop the Oil Pan. Just replace the Damper, Oil pump, Front seal, Timing belt, Tensioner, Idler perhaps Water Pump. While your in there do not skip the cam seal inspection.

Any second opinions?

[mrbrian200]

If the crescent at the bottom between the gear teeth where to get sheared across the face of the crescent. Pumping action would be lost because oil could freely backflow to the inlet side, also thin crescent shaped fragments would be spit out the outlet. A defective damper might create enough vibration to make it happen.

Any second opinions?

That's one way it could happen.
The theory I was working up was that the lobes wore down, or the clearance between the outer gear and the case became too great for reasons unknown (bad PRV? broken screen? Abrasive particulate contamination?). As wear increases a misalignment between the gears results in them crashing/binding as they come together on the pressure side. The stress of which would make the lobes susceptible to breaking clean off. Once one lobe breaks free it may still try to pump oil for a short while but this sudden more extreme misalignment with one missing lobe would snowball pretty fast into total failure, I would suspect. This might better explain the 'larger chunk' of metal he found.

There's always a second opinion. The question is whether it's any good.

[abscate]

That is such an elegant piece of engineering when you look at the forces and wear and how it is distributed across the lobes. Air cooled VWs use a simple double gear pump which works fine but always wears the seal plate so you have to rub it down on glass to flat.

Once this fits into 98v70dad's life a little better on time, he is going to slap a new pump in there, a couple of oil and filter changes, and drive another 100k. Engines aren't as clean as people think - and the filtration systems are pretty darn good.

[98v70dad]

Actually, everyone has overlooked the size and shape of the the big chunks I found and posted pictures of in my follow up post of Friday. I probably should have put them here but I chose not to thinking it was a separate topic. Anyhow, the parts are relatively large, 1/2 inch on the longest side of one of them and they are about 0.10 inch thick and fairly flat. There's absolutely no way they are from the gear teeth. Those gear teeth are beefy and any part that hypothetically broke off of on would not be flat and would not have a casting line on it. One of the parts has a casting line on it which you can see in the picture I posted. The part I have (take a look at the pictures in my other thread) looks like a piece of the oil pump housing although from the picture the housing looks thicker. It would have to be an internal part because i have no leaks. Also, a significant clue is that it has a golden shellac like hue typical of internal engine parts ON BOTH SIDES. One side also has some dark deposits typical of what you might find in a low pressure area - not sludge but sludge like in color. This would narrow down what part of the housing potentially failed.

It would help to know if there is an internal portion of the oil pump housing that could break off wit ha casting line running along it and is about 0.10 thick.

[abscate]

If you had a fracture defect it could absolutely crack straight but not machine tool straight. Can you put a flat on it and see if its machine flat

I still think your reasoning from the other thread are cogent, though. Big stuff on the downstream side of the filter has to come from the oil pump.

ITs a pretty easy tear down to get that out, just put the pump in, fire it up , and see if oil pressure comes up. You can do this with an hour or two each weekend without getting the boss too upset.

[98v70dad]

If you had a fracture defect it could absolutely crack straight but not machine tool straight. Can you put a flat on it and see if its machine flat

This is not a machined piece of material. Its a casting. There are no flat portions of the part. The pieces have been chewed up a bit by the gears but appear to have a radius - ie they are dished and probably came from one of the cantilevered dividers in the inner oil pump housing since they had oil on both sides and would be the most likely area to break off at the base. The picture seems to be thicker than 0.1 inches though. A gear tooth (or portion of it) could have broken off and caused the parts I found in the oil filter to shatter and break off. any hypothetical part broken off of the gear tooth could be potentially too big to go through the internals of the engine block - so hypothetically a fractured tooth or portion of a tooth could wreak havoc in the oil pump - both blocking flow and proper operation of the gears resulting in the housing failure.

BTW I was the "cracked part incident investigator" for many years at a previous job. I've looked at lots of cracked parts - even under the electron microscope. I can say with no doubt in my mind that the pieces I retrieved from the oil filter are not from either of the gears. They are too small, too thin and one of them has a casting line across it which you can see in the picture I posted.