Mercedes-Benz Forum banner

Exhaust smell

351 Views 12 Replies 4 Participants Last post by  samosali
probably one does not need to be super clever to make an assumption that exhaust can smell (on unburned fuel) due to bad valve seals. Does it sound reasonable for an engine with almost half of million km but most probably the odometer was turned back by previous owner, so I guess I am somewhere between 500 k and 1000000 km.

Is it difficult to replace valve seals, any special tools needed? Is it worth to try to get rid of this smell of unburned HCs? I have done with all other options, so ETA, lambda sonda and all this stuff is sorted.

Can I prove that it is valve seals somehow? Is CO or CO2 gasses somehow correlated with my issue?

There is no significant smoke out of exhaust pipes, but it is definitely present even when coolant is over 60 degrees C. the color is white. again, the smoke is barely noticeable.

Oil consumption is ca 1 litre/3000 km ... so I guess my question is rhetorical :) ?
Thanks!
1 - 13 of 13 Posts

· Registered
Joined
·
31 Posts
Hi! Oil consumption is ca 1 litre/3000 km - you need to repair engine -rebuilt. It is much. It can be done aprrox repair costs eastern europe 3000 eur and up. Depends on situation.
on unburned fuel - Can check spark plugs,distributor caps.
Do You have still have your original cats? or it is cutted out and replaced with aftermarket like Magnaflow etc?
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #3 · (Edited)
Hi! Oil consumption is ca 1 litre/3000 km - you need to repair engine -rebuilt. It is much. It can be done aprrox repair costs eastern europe 3000 eur and up. Depends on situation.
on unburned fuel - Can check spark plugs,distributor caps.
Do You have still have your original cats? or it is cutted out and replaced with aftermarket like Magnaflow etc?
Hi, thanks for your reply. I would not like to rebuild an engine in terms of complete overhauling. I guess pistons and cylinders are ok. Never had troubles with compression. I am leaning towards replacing valve seals (anything else??????) with head on a car, like i saw in youtube videos like this


Even if engine will go to complete overhauling I intend to do majority of work on my own.

Like i wrote, the car is properly maintained car (PMC), so the rest is perfect or close to perfect. Cat is WALKER original part made for Grand Cherokee 6l engine. so it is a part close to first installation on these trucks. at least data on the box tell me so, it was sold under MOPAR name. i have paid 400 eur for an old stock but the next one was sold for 1,200 eur on ebay by same seller in Germany. i hope it is much better than magnaflow, etc.
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #4 ·
i just have spoken with the mechanic whom "i trust very much" ( a discussable term). He claims that 1 liter of oil per 3000 km is ok and he strongly believes the engine is ok, too. To me this oil consumption seems to be extremely high and I am sure many forum members who will read this will be disgusted about his words. He thinks the car needs a diagnostics and he suspects lambda sensor. HA!

The truth is that lambda sensor is almost new and original mercedes part with star on it. I do all jobs except transmission and body on my own so, i cannot imagine what he can do with coupling the diagnostics onto OBDI.

so it seems i will leave things as they are because i am not willing to search for luck if things are not completely clear.
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #5 ·
It can be done aprrox repair costs eastern europe 3000 eur and up.
hehe .... eastern europe?

Slovenia never was and it is not a part of eastern Europe. Never in a political sense, never in geostrategic sense.

In most definitions Slovenia is part of Central Europe.
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #6 ·
this is interesting because it says that M119 engine burns (can burn) 1liter/1000 km of engine oil:

so i can say that 0.3 liter/1000 km in my case is favorable and in theory i can forget engine overhauling. the problem is most probably somewhere else but i have no idea what it might be. teh car was scanned with SDS zillion times and all relevant parameters were ok, so no use to use gadgets on this old lady.
 

· Registered
Joined
·
31 Posts
i just have spoken with the mechanic whom "i trust very much" ( a discussable term). He claims that 1 liter of oil per 3000 km is ok and he strongly believes the engine is ok, too. To me this oil consumption seems to be extremely high and I am sure many forum members who will read this will be disgusted about his words. He thinks the car needs a diagnostics and he suspects lambda sensor. HA!
On normal m119 is no need to add oil. If engine eats oil it - it need to rebuilt. Mechanic who says that is ok - is poor educated.
You need to check compression too. How to do shown lower:
Lambda - ask connect to star diagnosis car - do checks, ask for print reading report and show here in forum. Car has obd port to connect pc.
Do all test.

Hi, thanks for your reply. I would not like to rebuild an engine in terms of complete overhauling. I guess pistons and cylinders are ok. Never had troubles with compression. I am leaning towards replacing valve seals (anything else??????) with head on a car, like i saw in youtube videos like this
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #8 ·
On normal m119 is no need to add oil. If engine eats oil it - it need to rebuilt. Mechanic who says that is ok - is poor educated.
You need to check compression too. How to do shown lower:
Lambda - ask connect to star diagnosis car - do checks, ask for print reading report and show here in forum. Car has obd port to connect pc.
Do all test.
I share your opinion about oil consumption. In addition, I own this car for last 190k km and I am pretty sure oil consumption is now 100% more than in the beginning.
BUT still ... data is data and the allowed oil consumption is much higher then the present one, so I cannot be 100% sure engine overhauling will give expected results.

BTW. the difference between "no oil consumption" and 1 liter per 1000 km is actually neglected in practice. If only several molecules of oil pass the valve stems in one turn of engine, then one liter in 1000 km is not so much if you consider how many revolutions engine makes in 1000 km ...

I think the above is a reason why people's experiences about oil consumption are so different. namely, some people, unlike you, report much higher oil consumption than you and at same time they are happy with engine performance.

Unfortunately i cannot know a real mileage of the car. turning odometer back when selling the car is a national sport in these places.
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #9 · (Edited)
On normal m119 is no need to add oil. If engine eats oil it - it need to rebuilt. Mechanic who says that is ok - is poor educated.
You need to check compression too. How to do shown lower:
Lambda - ask connect to star diagnosis car - do checks, ask for print reading report and show here in forum. Car has obd port to connect pc.
Do all test.
compression was measured not so long ago and it was within limits. the car was many times on SDS; in a shop and on the road. Values are close to perfect. I spent more than 40 k eur and hundreds of hours in last 15 years and once it is simply enough. My original question was launched with having in my mind to do the project on my own. But now the information which i have is extremely controversial, so i will not do anything because the result is not clear. I have read on many places that 1 liter of oil per 3000 km is not over the allowed limit for this car, i have to consider many opinions, not just one. I work on bikes and cars from age of 13 and I have some sense for these things, in this case i just feel things are not clear enough. something is wrong with this car however i doubt it is valve seals or anything else like that.
 

· Registered
W140 Mercedes 500 SE, 1992, European, 440.000 km
Joined
·
4,420 Posts
Discussion Starter · #13 ·
Oil leak? Intake hoses?
I have this issue in both of my mercedes. I refil 1lit after 3000 then complete change at 7000 or a bit before.
no oil leaks for sure. things are dry, here and there there is some oil on engine but not enough to form drops.

which intake hoses do you mean and how are they related to high oil consumption, i do not get it.
 
1 - 13 of 13 Posts
Top