Deadbolt9009

Hi there.
I am purchasing a 1991 W201 190E 2.6 in the coming days. Vehicle has just shy of 199,000 miles. Drove it yesterday and for its age and mileage it appears to be very solid. No major rust. Owner states that it uses oil mainly to leaks. I plan to do oil analysis after I bring it home. Question…what is the average oil consumption to those that know for this old timer Mercedes?

190Efan

Ideally, you shouldn't be using more than a quart between oil changes. If the car is using more than that then there could be some additional issues. I would suggest purchasing some engine dye from your local parts store, running that in the engine in order to identify where the oil leaks are and how serious they might be. I would also suggest that you check the head gasket and see if there's any documentation that it's been replaced. The M103 engine that's in the 2.6 is notorious for blown head gaskets. I would also advise you to make sure that the car has been properly maintained on a regular basis as a car with lots of deferred maintenance might be best to walk away from. You might also want to consider having a pre-purchase inspection done by an MB expert to be sure that the car doesn't have any serious major issues that could cost big money to correct.

Deadbolt9009

Thanks for your input. For what I am paying for the 190E it is worth having to deal with oil consumption issue that former owner reported. He swears it is not the head gasket. Will investigate further…And I’ll do my own work if needed. Again…Thanks!

190Efan

Glad to help you out. I own a 2.3. FYI, there's nothing more expensive than a cheap Mercedes-Benz. I would urge you to investigate carefully before you purchase as you could be walking into quite a money pit. Previous owner not fixing the oil leak would be red flag for me.

dolucasi

Not sure if you ended up purchasing this car but it is quite common to have oil burning for a 200K mile engine IF it was used regularly as a daily driver for short distances.
Even if it was maintained like my car. What wears a properly maintained engine is cold starts. I am burning about 1 quart/500 miles at 200Kmiles. I am the original owner and know the history.
My car has been started cold 40K times, used <5miles per trip for 30 years. Same mileage that was driven 20 miles per trip will last a lot longer. Probably over 300K miles.

BTW I have already had the head re-done, guides, valve seals etc. I am convinced it is the piston oil rings (worn). Will need a engine overhaul at some point. Currently just add oil once a month.
No compression issues whatsoever.

In your case if the engine never had the valve guides done, that will improve matters by a factor of two.

190Efan

Glad you've made the move from BW as have Your W201 expertise will be much appreciated. I. Even though I know your car has been very well cared for, I have to say that my engineer father would consider your having to add a quart of oil every 500 miles to be excessive. Sounds like you've got some pretty good blow by happening somewhere. I also think warn piston rings might also be the likely culprit given the work you've done and I agree that it looks like an engine overhaul is in your future. My engineer father also always made sure to take our cars out on the highway on the weekends for some highway driving and to blow out the carbon build up that happens from the numerous short around town trips. Thanks to my engineer father, my W201 has only ever had the synthetic Mobil One in it ( he actually knew the man at Mobil who originally developed Mobil One) and synthetics go a long way towards helping to reduce engine wear. I'm also curious if the OP ever purchased the W201 they were looking at.

dolucasi

Hey, good to meet you here again 190Efan. My engine has almost zero blow-by. I measured crankcase pressure and intake pressure simultaneously to get to the the bottom of the oil burning.
Also, there is no oil making its way into the intake thru the breather hose. Super clean there too.
So it is not the compression rings.
After this and the compression and leak-down tests I have conducted, and also the observation of the condition of the cylinders during the head job when it was removed (with all the honing marks still in tact) my conclusion is that either the oil rings are worn or stuck letting oil into the cylinders. Oil burning is rather even in all cylinders, meaning the spark plugs get fouled evenly on all 6.

BTW, I have flushed the engine twice to see if I can release the oil rings, and unfortunately, the oil burning went from 1000mi/qrt down to 500mi/qrt. So all the build-up in the piston rings/cylinders must have been helping with the oil burning. Wish I had not done the flushes.

I will only know for sure once the engine is opened up. Currently the engine (and garage) is occupied with my son's Miata Engine rebuild. So we wait....

- Cheers!

190Efan

You've certainly done all of the right testing as I knew you would. Maybe the increase in oil consumption after the engine flush might indicate some weakness in various rubber bits that've become brittle over the years might be a contributing but not the only reason. That sure seems to be excessive oil burning for no blow by. I agree, I also think the only way to really find out for sure is to open the engine up when your garage becomes available. I'll be curious to know what you eventually find out. In the meantime I would advise carrying a couple of quarts of oil with you when you drive your W201, just in case.

natejgreene9871

My 1992 190e 2.3 with 195,000 miles burns no oil. Zero.

But the cylinder head has been rebuilt...

dolucasi

Nice to see you here Nate! Yes I am puzzled too since I also have my head re-built. I know my #5 cylinder is a little worse than others.
And the engine flush made it worse by a factor of two.
I will only know when I pull the engine some day. Till then we just add a quart every other fill up....

Have any idea how many highway miles on your car?

natejgreene9871

Honestly no idea but the carfax is pretty helpful. It's basically my only records.
Interesting that the dealer opted to replace the entire head assembly when the gasket blew in 2004. So, it would be on its second head gasket at this point.

355190e26

I think that's typically how the dealer services things. If a part breaks, install a brand one one rather than re-condition the old one.
I just did a cylinder head swap last year on my green car, but in that case the machine shop had a refurbished head ready to go that he needed to dump.