Normal oil consumption?

[Ron in SC]

Vehicle is a 92 300 TE with about 140K miles.

It uses about 1 quart of oil 15W50 mobil 1 every 1750 miles with about half highway and half city.

Does that sound about normal? Vehicle does not leak any oil.

I think valve stem seals were replaced when head gasket replaced at 81K miles.

I could replace valve stem seals but not eager to do so.

[RBYCC]

Originally Posted by Ron in SC

Vehicle is a 92 300 TE with about 140K miles.

It uses about 1 quart of oil 15W50 mobil 1 every 1750 miles with about half highway and half city.

Does that sound about normal? Vehicle does not leak any oil.

I could replace valve stem seals but not eager to do so.

If you see no leaks then it must be burning oil....

Your consumption is too high.
Suggest switching away from synthetic as you're wasting money at the rate of use.

Valve stem seals would show blue smoke on initial startup.

No seepage anywhere on the cylinder head?
Any oil in your radiator?
Do you see blue smoke from your exhaust?
Have you removed and read your plugs to see if oil coated ?
Looked into your air filter housing to see if oil is being sucked in?

Obvious you have engine wear, so why not try a conventional oil designed for high mileage vehicles ?

[deanyel]

Depending on age valve stem seals could be bad again.

[Ron in SC]

Valve stem seals would show blue smoke on initial startup.

This car does not have blue smoke on startup nor did last M103 motor I replace stem seals on either.

No seepage anywhere on the cylinder head?

None

Any oil in your radiator?

None

Do you see blue smoke from your exhaust?

No

Have you removed and read your plugs to see if oil coated ?

Yes, they look great

Looked into your air filter housing to see if oil is being sucked in?

None. Also none in intake manifold in the area where it can collect.

[babymog]

No reason not to use Synthetic, use what you like IMO. If it's your last $20, it's different and time to sell the car ;~) Conventional oil has in my experience always burned faster in my high-mileage cars that consume oil, which is expected.

As long as you stay away from products like Slick-50 you're doing no damage to your engine with good oils.

Originally Posted by RBYCC

If you see no leaks then it must be burning oil....

Your consumption is too high.
Suggest switching away from synthetic as you're wasting money at the rate of use.

Valve stem seals would show blue smoke on initial startup.

No seepage anywhere on the cylinder head?
Any oil in your radiator?
Do you see blue smoke from your exhaust?
Have you removed and read your plugs to see if oil coated ?
Looked into your air filter housing to see if oil is being sucked in?

Obvious you have engine wear, so why not try a conventional oil designed for high mileage vehicles ?

[RBYCC]

Synthetic oil is more apt to internally burn off in a high mileage engine.

You don't show the typical symptoms so why not try a change to a conventional or semi synthetic to see if the consumption lessens ?

I'd consider Castrol GTX High Mileage 10W-40 semi synthetic.
You're in a warm climate so the higher viscosity is not a problem.
The oil contains additives that will condition seals.

Mobil has a similar product that reduces internal consumption.

[babymog]

Not trying to be argumentative, but based on what?

I've always read and experienced the opposite, and the formulation with higher flash-point and less aeromatics in a true synthetic would support it's lower evaporation and combustion rate.

Originally Posted by RBYCC

Synthetic oil is more apt to internally burn off in a high mileage engine.

[Tomguy]

Originally Posted by RBYCC

Synthetic oil is more apt to internally burn off in a high mileage engine.

Actually, in my experience synthetic doesn't burn nearly as much as conventional. My Jeep has 173K on it and doesnt even go through a quart typically between 4k changes DESPITE blowby visible in the CCV tube.
However when I last used (the same grade) conventional over 30k miles ago it used 2 quarts.

Even when I used 5w30 2 winters ago in the engine (first synthetic I put into it) it didn't use a full quart in the 3000 miles from December to March (when it was too warm to keep it in).

With your consumption, are you 100% sure you dont have a leak onto the manifold that's burning off? Otherwise it could be valve guides...

[Ron in SC]

With your consumption, are you 100% sure you dont have a leak onto the manifold that's burning off? Otherwise it could be valve guides...

I'm sure I don't have a leak.

I called Mercedes dealer and spoke with service person and asked for acceptable oil consumption for 1992 300TE. He said 1 liter per 1000 kilometer. I asked if he was kidding and said yes that is what Mercedes claim is acceptable. Personally I think that's ridiclous, but that what he said.

I also taked to my friend that owns an independent MB shop and he said that with that consumption I would not have fouled spark plugs; he was not suprised that the plugs looked fine.

For now I'm not going to worry about it. Maybe the next time I change the oil I do valve stem seals.

[Ferdman]

Ron, that level of oil consumption is nothing to be alarmed about. Some new engines can consume 1 quart of oil every 1,000 miles. Only add enough oil to reach the midpoint between the high and low marks on the dipstick, then check the rate of oil consumption. Our 124 car engines use less oil when I follow that practice. By the way I use Mobil 1 15W50 exclusively in our 124 engines.

[Ron in SC]

Our 124 car engines use less oil when I follow that practice. By the way I use Mobil 1 15W50 exclusively in our 124 engines.

Fred,
I always fill to a little less than high mark on dipstick, so when oil is hot level indicates full on the dipstick.

I will try filling to halfway between high and low mark and monitor oil level.

I know what people say about using Mobil 1 in our cars. I use synthetic oil in all my cars and I have no intention of changing.

[tilac1]

I use Valvoline High Mileage oil in my '88 300E more because of the car's (and seals) age than the miles: 50K. The PO swore by Mobil 1 but I found the high mileage dino blend gets consumed less. Price is also a factor. I follow MB schedules and use German filters.