For those of you who have 'dealt' with the rear main seal issue, I am wondering if you ever quantified the amount of oil you lost.

I have a 1993 960 with good compression and no leaks through camshaft cover, rebuild head, sealed rear camshaft cover etc, that still uses 1 quart (1 liter approx) per 300 miles.
I noticed that the smal hole underneath the transmission bell housing is wet, however no oil stains on cardboard underneath.

I was wondering how much oil I can loose through a leaky rear main seal.

Thanks in advance for your response.

Robert

Hmmmmmm....

My belief is that if you are seeing no external oil dropping under the car you have an insignificant leak rate.

I have a similar situation with my car. I think the oil is being burned even though I see no smoke and the engine runs smooth with good power.

See my post of a couple days ago. "I'm going to try Auto-RX"
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'96 965, 16' wheels, Michelin Pilot Sports, rear 18mm bar + Koni, 201 HP cams, 129K. Put 200K on '85 745 TD.

You will not lose as much oil through that rear seal leak as what you are going through. If there are no spots of oil on the ground when the car is parked over night-no way is 1 quart every 300 mile is coming through that.
I would try the Auto r-x treatment-try their website for details.
Hope that helps
Poolman

You may want to also check the oil cooler area to see if it is leaking or if you have a leaking oil cooler hose.
'97 960 101k miles

This car and yours does not have an external oil cooler with oil hoses! The oil cooler is water cooled and is between the oil filter adapter and the oil filter.
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'96 965, 16' wheels, Michelin Pilot Sports, rear 18mm bar + Koni, 201 HP cams, 129K. Put 200K on '85 745 TD.

You may want to also check the oil cooler area to see if it is leaking or if you have a leaking oil cooler hose.
'97 960 101k miles

You may want to check the oil cooler area to see if it is leaking or if you have a leaking oil cooler hose.
'97 960 101k miles

external oil cooler it is, little bit of a sweaty hose near the fitting, nothing that would cause this enormous oil use. Some have suggested that one or more valve stem seals might be leaking. What do you think, could that cause all the oil to disappear?
Compression test 185 - 200 psi is pretty good, isn't it?
Robert

Those readings are just barely ok. Should be 184-213 per the book. And your are within 10% of the high and low, which is also just ok. In my opinion, most likely you are burning the oil, just not seeing out the tail pipe. I wonder what a leakdown test might show. With that test you will get a idea of ring wear.

Bought my car with 16,000 miles on it and the best oil consumption ever was around 1,500 miles to the quart. The engine compression was was about 220 across the board give or take a pound or two at 16,000 miles.

At 171,000 miles the compression was 75-175 and the leakdown test, the best cylinder was 75% and the worst was 13% all of those numbers improved with oil squirted into the cylinder. By then I was nearing 500 miles to a quart. Putting another 60,000 miles on the clock, oil consumption was more like a quart every tank of gas. The only time one would ever see blue smoke was if you accelerated quickly from the first start up of the day and then just a few hundred feet down the road. Maybe the catlytic converter needs to warm up to get all the oil burned cleanly. By then there was nearly 220,000 miles on it.

After replacing the engine and tearing into the old one, it was the rings and the top end of the cylinders that had heavy wear. I had used dyno oil for it's life, went no longer than 4,000 miles between changes. The engine had no oil sludge anywhere. There was some carbon build up at the bottom of the cylinders caused by the blow-by. The ring grooves in the pistons had worn, the rings themselves had not only worn in their circumferences, the edge that contacts the cylinder wall, but the pistons grooves had worn a scallop into the ring top and bottom surfaces as well, making them much thinner. Even at 234,000 miles the cylinders had the cross hatching from the factory hone, except at the top of their travel. The main and conrod bearings had little wear, almost good enough to use in the new engine. That's for a car that had maybe an average of 20-30 start ups a day.

Betting your oil is going out the tail pipe. When you get the oil changed, how long does it stay clean? How black is it when it is time for a change?



DanR 94 964 290,000 miles (56,000 on the new engine) Comp. 230# per cylinder.








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DanR

Thanks for your detailed reply.

Here in MD we have State Emission inspection, all the emission numbers were typical Volvo low. Maybe the cat helps clean up the combustion gasses.

Before the timing belt failure, oil consumption was less than a quart per 5000 miles. The head was rebuilt and then it started to be high oil consumption.

With a quart every tank of gas it stays pretty much clean, since we use synthetic we haven't felt compelled to change it either. Wifes drive 6K-8K a year.

Did you get a rebuild engine or one from a low mileage car?

How do you perform a leakdown test?

We have emissions testing too, the car always passed until about 180K, then a new cat was required to pass the tests. The last cat on the old engine did not last 60K miles before needing to be replaced.

The leakdown test was performed by my volvo mechanic. It is a matter of manually turning the engine over to get the valves closed on a particular cylinder with the piston at the top of the stroke. Using a prescribed pressure of air and a pressure guage, then allowing the cylinder to leak down over a certain amount of time. The longer it sustains the pressure or leaks down no more than a certain percentage the better. I do not know what the numbers should be.

Your problems is very similar to fellow poster JBowers, he will be doing a leak down test shortly. He had the head off too, and after the repair noticed a marked increase in oil use. His head was not touch though. It will be interesting to see his results.

Spook is correct in the machine shop is critical in the refurbishing of these heads, they must have an understanding of european heads esp. BMW, VW and Porsche. Something could have been overlooked. To do guides correctly, one needs some special heating and chilling equipment.

As far as the engine swap, the new engine was never in a car, it was a teaching tool for area volvo dealers when the 960 first came out, it had the wire harness, all of the sensors, covers and pulleys. But it had it's problems, first was the engine was 13 years old, so it had some light rust on some of the steel parts, the bolt holes were stripped out, I think 120 bolt holes out of 170 needed to be repaired. It needed new bearings all around, it was missing a few valves and valve guides and need new piston rings.

I brought the engine in it's separate pieces to a local shop that does work on mostly foreign and exotic cars. He lightly polished all of the mating surfaces, reringed the pistons, he took the time to match each piston and rings to it's corresponding cylinder. Took all the pieces home and did the assembly my self.
Found a few more bolt holes that needed repairs along the way, the machine shop lent me all of the necessary tools to take home and finish it off.

After all of that, it still uses oil, but it is different than the old engine, the oil remains clean between oil changes. Uses about a quart every 1500 miles. I think the cause is the valve seals were at least ten years old that were used. Did not know that at the time. I have so far in almost 60k miles since, replaced all of the cam seals because of leaks, they had hardened up and cracked. That is why the valve seals are targeted, it was all part of a head kit, So sometime in the future I will pull the head and have that done.

Good luck and keep us posted. (56,000 on the new engine)

DanR 94 964 290,000 miles




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DanR

Now I am doubting the position of the piston on the leakdown test, not sure if it is up or down. Well someone will correct me.

DanR 94 964 290,000 miles (56,000 on the new engine)
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DanR

Dear volvo4fun,

Good p.m. & may this find you well. Was the head rebuilt by - or under the supervision of - a Volvo MasterTech?

I wonder if some of the valve guides - perhaps inobviously damaged when the timing belt snapped - are the root of the post-rebuild, high oil usage.

Yours faithfully,

spook

Automotive machine shop did the job. Almost all of their work is boring out cylinders, and rebuilding heads. It is possible that they missed something.

I am planning on removing the head to see what is up.

My wife likes the car so much that she doesn't mind putting oil in every tank of gas.

It is interesting, when I discussed my oil 'disappearance' with the MT at a friendly Volvo dealership, he immediately replied that he thought it was leakage around the valves stems.

At this point I am close to having exhausted all other causes, I will do a leakdown test (if someone tells me how to do it) just to make sure and then remove the head.

Thanks for your thoughts on this matter.
Robert

Dear Dan R,

May this find you well. My 93 940's prior owner had a mechanic, who knew not about flame traps. Rear main seal leaked a few drops of oil, once parked. It perhaps took a pint (16 fluid ounces) every 1,500 miles. I had to rear main seal replaced, when some other, unrelated work needed doing.

The engine has 114K miles. It burns / uses no oil between changes (every 3K miles, with Mobil 1). Mobil 1 is slowly cleaning the engine. The camshaft working surfaces used to have an orange/brown varnish on them. Last time I looked (after 13K miles with Mobil 1), those surfaces were clean.

If an engine is losing a quart of oil/300 miles through the rear main seal, there will be a puddle of oil - 6 inches across - beneath the car, whenever and wherever it is parked. If there's no oil puddle, then the rear main seal is not the culprit.

Yours faithfully,

spook

I agree, there would also be a burning oil odor at almost every stop, with all of that oil splashing the under side.

I have bought 6 brand new vehicles in my life (32 yrs driving) and never once was there one that did not need oil between changes. When people say that I alway scratch my head on why are they so lucky and I am not. Maybe it is my driving style, enviroment I don't know but is it really possible to have an engine not use any oil? I would think that shear volitility would account for some oil usage. I can't use any of the used cars that I have had over the years because of not being real sure of how the PO maintained them. If I throw those into the mix, still never had a car that did not require oil between changes. Some of those cars were fed Mobil 1 too. I live in the Chicago area and drive through rush hour traffic, so maybe my car use could be classified as that of a taxi cab, lots of idling and bumper to bumper driving.

I will say though, that using Mobil 1 since about 10,000 miles, the cams are still the same color and there is no varnish building up. So there is a difference already.

DanR 94 964 290,000 miles (56,000 on the new engine)
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DanR

I bought my 850 T5 Wagon new in 1995. It has never seen any dino oil. I go 5000 between Mobil 1 changes. I check ever now and then, but never add oil.
Basically the same engine design as the 960.