Fix it or pass it along? - PeachParts Mercedes-Benz Forum

Vintage · #1 09-30-2022, 03:52 PM

Hey all. I've been away from this forum for a while but thought I'd check in for some "professional" advice. I have a 1965 190D that I picked up a couple of years ago and it became my Covid project. It runs and drives but she's smoky. Combusted gasses are entering the case and puffing out the dipstick vent. Some oil blow out here as well.

It (at least) needs a head gasket and likely rings. I'm more of a gas motor guy but I do have some diesel knowledge. The car shows roughly 10,000 miles on the odometer and I have no idea if it has made the trip around once or twice. Overall wear supports 110,000 but hard to say for sure.

I've cleaned it up, touched up some paint, changed steering column bushings, redid brakes (including replacing the booster). I'm torn - I have several cars and enjoying puttering with them and I'm on the fence here. I'm tempted to sell it to a "diesel guy" but it shifts and drives so well that I hate to part with it.

Is a head gasket kit available for the OM621? Worth starting there and seeing if that improves things?

I'll post up a few photos. Have a look and feel free to chime in.

Thanks!
Eric

BWhitmore · #2 09-30-2022, 05:24 PM

It is a beauty and certainly worth an investment to get her running great.

t walgamuth · #3 09-30-2022, 06:08 PM

Is it a stick? I had one like that. Might be poor crankcase ventilation. Did you run a compression test? That engine is one of the simplest ever to work on.

Vintage · #4 10-01-2022, 10:43 AM

Hi,

Not a stick - four speed on the column. I'm amazed how smoothly it shifts and drives for a car that sat idle outdoors for years. Very little rust other than the usual spot behind the passenger front wheel. Plenty of dings/small dents. Looks like someone with a bb gun used the front glass for target practice.

I have not done a compression test. Interesting thought about the case vent. I don't have a shop manual for it but it appears it vents through the dipstick tube? There is an air screen there.

I changed the oil and it did not take long for it to become coal black so my assumption is combusted gas is really blasting into the case. I need to pull it out (has not been driven in 6 months) and have a look at the venting.

Back to my question - is a head gasket available? I looked some time ago and had no luck finding one.

It really is a neat car. The AC even took a charge and blows cold.

Thanks!
Eric

psaboic · #5 10-01-2022, 10:49 AM

Coal black oil is not indicitive of a serious engine issue. Every diesel I have ever had, including my current 83 300D, 2002 TDI, and 2012 ML350 turn fresh oil coal black within a couple minutes of starting. Its a diesel thing

Sugar Bear · #6 10-01-2022, 03:48 PM

VERY nice car...if you like the car it is worth fixing. IF it needs an engine I'd consider using a 240D from a 74-76 due to additional power.

Is a head gasket available, I don't know but would ask the MBZ Classic Center.

I think that engine has an oil sump bath injection pump. Look for a cap that says OEL on top of the pump. Change the ancient oil in there otherwise the pump may seize.

Adjust the valves.

Coal like oil is perfectly normal even on a fresh engine after an oil change. Use C rated diesel oil, Rotella, Delo etc.

Make sure it can breathe.

Chemical soak the rings and drive it hot and hard. Run it full throttle uphills and let it coast down hill repeatedly to work the rings free after a soak.

Use fresh diesel fuel.

Compression test is a great idea, adjust the valves and run it hard first. If it starts easily the rings should be ok except for the oil rings possibly being clogged (ring soak).

Again that is a SUPER nice car, if you like it fix it but remember a 190D in great shape is S L O W. Consider a later 240D engine

Good luck!!!

Junkman · #7 10-01-2022, 08:29 PM

Price just because? Sell it and ou'll be sorry.

BillGrissom · #8 10-02-2022, 02:42 AM

Turn the engine over by hand. On my 1985 300D, I can do that easily with a 22 mm wrench on the power steering pump pulley at the top of engine. If you feel each cylinder strongly resist you over 2 revolutions, indeed must wait for each to hiss down, the engine is basically fine with no valve, head gasket, nor piston ring problems.

JHZR2 · #9 10-02-2022, 03:37 AM

Nice looking car. You sure don’t see diesel fin tails everyday. One of my dream cars if I could find one so nice.

Benzadream · #10 10-02-2022, 08:52 AM

She's a beauty alright. My vote would be "keep it". Especially considering the great space you have for such indulgences (assuming the pics are from your place). Not to mention the Carolinas, which have about perfect weather for "collecting". My bet would be the odometer has not "turned over"....the interior, which is in amazing condition, tells a different story IMHO. As does the exterior condition of the car, for that matter. Although, anything's possible, I guess. If it has turned over, this was obviously a really well cared for automobile. A couple pics of the engine would be great (and also helpful in making a determination). Even at 110K, she's just gettin warmed up!
As someone already mentioned, don't let 'er go. You'll definitely regret it.

Vintage · #11 10-02-2022, 08:36 PM

Hi all,

Thanks for the input. I do agree that I might regret it, but I think I will sell it. It was a fun project over Covid but probably not a car that I'd really ever drive. My wife accuses me of bringing home too many "strays" and she's not wrong. If I pass some along it helps keep the peace. And considering I just adopted an early 70s 280C, now might be a good time.

I am happy to share all that I have done to the car if someone is interested. I'd really like to see it go to a good home so I'm only looking to recover what I've spent to date. The car has a clean SC title in my name and is currently registered. It is driveable but until the engine gets a good going over, I'd trailer it any distance. I have a lift and I'm happy to provide photos of the work done and current condition.

As many of you noted, there is a lot of good about this car but it has its flaws. Consider it a good place to start a restoration. I'll be away from SC for the next week or so but available to answer questions anytime. I guess a PM would be best. I'm happy to share that I have about $6k invested into the car and I'd like to recover that amount. A car cover will come with it as well.

Let me know if you're interested.

Vintage · #12 10-02-2022, 08:52 PM

I know this is a diesel forum but I thought you all might like to see one of my more interesting MBs. The 170v did come in a diesel variant as well (in fact I have several diesel manuals if anyone wants one) but this car is the petrol inline 4. Makes a whopping 38hp but that moves it along as fast as I need (or dare) to go.

Enjoy the pics.

Diesel911 · #13 10-03-2022, 11:51 PM

Quote:

Originally Posted by Sugar Bear

VERY nice car...if you like the car it is worth fixing. IF it needs an engine I'd consider using a 240D from a 74-76 due to additional power.

Is a head gasket available, I don't know but would ask the MBZ Classic Center.

I think that engine has an oil sump bath injection pump. Look for a cap that says OEL on top of the pump. Change the ancient oil in there otherwise the pump may seize.

Adjust the valves.

Coal like oil is perfectly normal even on a fresh engine after an oil change. Use C rated diesel oil, Rotella, Delo etc.

Make sure it can breathe.

Chemical soak the rings and drive it hot and hard. Run it full throttle uphills and let it coast down hill repeatedly to work the rings free after a soak.

Use fresh diesel fuel.

Compression test is a great idea, adjust the valves and run it hard first. If it starts easily the rings should be ok except for the oil rings possibly being clogged (ring soak).

Again that is a SUPER nice car, if you like it fix it but remember a 190D in great shape is S L O W. Consider a later 240D engine

Good luck!!!

Yes.
My Volvo GL244 sat for a year and when I got it stated it had a gray haze of smoke all of the time and worse when I stepped on it.

I did not think it would work but for $7 I bought a large bottle of Marvel Mystery Oils and removed the glow plugs and got a funnel with a tube on it and filled dumped a half cup into each cylinder and let that soak for a week.

I rotated the engine and dumped in more MM oil intending to soak for another week but had to get the car going after 3 days.
Drove it around the corner to my driveway and changed the oil. Note the MM oil is going to thin your crankcase oil.

As said, I took it for a drive on the Freeway and a good deal of the gray haze cleared and after another 3 or so days it was gone. I was totally surprised it worked.

I did the same to my 84 300D with zero better results.

Others have had the soak increase their compression.

So, it only works if your rings are sticking.

Others have said switching to synthetic oil and driving for like 200-300 miles will also free up sticking rings.

Diesel911 · #14 10-04-2022, 12:02 AM

Some other issues. Depending on the type of valve stem seals it uses the seals could be shot and or there could be too much clearance in the valves. That allows exhaust gases to get into the crankcase past the valve stem.

If the fuel injection pump has pneumatic governor vacuum leaks cause it to have a higher fuel output and they smoke. Also, the diaphragm gets stiff and develops over time.

Concerning head gaskets try looking on US eBay or UK eBay. I believe the 621 at one time was used as a diesel generator engine for refer units by Thermoking.

Best to find a Mercedes parts site that has the mercedes part numbers and get that number and do a search with the part number.

If you did a compression test you should be able to tell if the head gasket is leaking combustion gasses into the crankcase. The other issues would be an exterior coolant leak from the head gasket or combustion gassed getting into the coolant.
If you are not having those you don't have a head gasket issue.

Another way is to get the piston up on top dead center on the compression stroke so that the valves are closed, and you apply compressed air to the cylinder, and you listen to where the air is hissing out of it. It can also show up a cylinder head gasket issue. It will cause bubbles in the coolant or air will hiss out of between the head and the block. However, remember your radiator cannot take the high air pressure so you either reduce the pressure or remove the radiator hoses from the radiator and plug the hoses off.

Vintage · #15 10-04-2022, 12:51 PM

Hi All,

Thanks for the continued replies. Some clarification - the engine starts easily after 5-10 seconds on the glow plugs. Runs smoothly and idles fine. No black or grey smoke on startup. The smoke is blue (oil) and starts after 20-30 seconds. After giving it some thought, I’d guess valve guides.

Agreed on the usefulness of Marvel oil. I’m a licensed A&P aircraft mechanic and we use that for waking up old, stuck rings and cylinders. Generally works well.

Good advise on the injector pump oil. That reservoir was low but not empty.

I need to spend a little more time puttering with this. I’ll adjust the valves next.

Thanks!
Eric