My experience has been to do a compression test first. One "dry" the other "wet" if you have a low reading. You then add some engine oil to the cylinder, and re run the test. If the compression numbers come up, then the rings are suspect. If the numbers do not come up, some thing else is wrong, like burned or poorly adjusted valves, bad head gasket, etc., so then you do the leak down test.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

You sure make that sound easy. Which route do you use for adding the oil ? And , are you using the injector hole or the glow plug hole for your compression guage ?

I wouldn't suggest doing this to a good engine but heres what I did after finding LOW compression on a TD I bought. (I couldn't get it started by towing.) I needed to get it started to make a determanition of how it "drove". I squerted a 50/50 mix of lub oil and ATF into the GP holes, enough to hydro lock the engine when turning by hand, waited a hour or so, engine not locked anymore. It fired right up long enough to drive around a couple a couple hours and check out the car. That was really a 'last ditch" effort.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Your rings could be stuck too since your engine has probably sat for a long time. Try to free up the rings once you get it to where you are going! To do this you will need to have the engine running. Let it warm up to normal operating temperature and then slowly feed a stream, small stream of water into the main plenum of the intake manifold while holding the engine at about 2500 RPM. SLOWLY pour in about a quart and watch the steam coming out of your tailpipe. DO NOT stall the engine with too much water!! You could take your compression test first and then do what I said and let us know what happens! The moisture from hot water being compressed into the cylinders while the engine is running will help loosen the carbon that sometimes gets lodged into the rings and causes them to freeze to the pistons. Especially if the engine you installed has been sitting for a long time without starting. Keep us informed!

I don't want to offend anyone... but really, that is the craziest thing I have ever seen posted on any forum at any time... no offense intended... LOL

Here is the critical physics question. Do you actually know how small the distace is from the side of the piston to the bore in these engines ?

Yes!! And the 16 years I spent as an Engineer at the Chrysler Corporation taught me that this works! I know it sounds crazy but trust me! We used to do this a lot on test engines after a really good pounding and water will free up and loosen stuck carbon in the rings! The hot steam will definitely help even though you might have to do this more than once! I've worked on many diesels produced for Dodge Trucks!

that water deal is definetly an interesting though. The motor has not been sitting though, I pulled it from a running car and installed it over a year ago. since then I've put 20k miles on it with no problems. Last time I drove it was yesterday. I'm game to try this steam cleaning of the rings, but how do you suggest it get it in there what with the air filter and turbo in front of the intake manifold? honestly I think this thing is just wearing out, so I'll be carrying a can of wd-40 from no on!

Where are you in nova scotia? What really bothers me is adding oil to the cylinders could only be useful for one start and run. How come you got so much time till your problem returned? Did the ambient temperatures really cool off over that time? What is the reason the problem is back? Since they were kind enough to charge you three hundred dollars at least you should have the compression values. If not get them. You cannot make any real decision in my opinion otherwise. Did they do a test to confirm the rings? Could as well just be tired valves otherwise. For example improving the ring seal might have given just a little more compression to overcome poor valves. Or still something else.
That engineer is not crazy. What might be crazy is my agreeing with a chrysler engineer perhaps. Forgive me I just could not hold it back.
The water injection we used to use as a decarbonising agent on older gas oil burning engines we brought. If by any chance you decide to try it make sure the engine is warmed up to operating temperatures first. And meter the water in fairly slowly. On gas cars we flowed it in faster than I would with a diesel. I cannot personally express an opinion on the results with a diesel. Neither can I personally vouch for it with a diesel. We just were trying to decarbonize the general chambers and piston tops on gas engines. It never occured to me it might have some value with the rings. I do not remember the consumption rate of oil dropping but then again the effect did not reach the oil control rings probably. They also were less likely to be carbonized. It did work as the carbon blew out the exhaust I remember. That was a long time ago come to think of it. Think 39 fords 46-48 fords etc. I was not alone in this practice either. It took this mention to even remember it. A lot of those earlier engines burnt some oil and a percentage baked to carbon. In no case that I am aware of did the introduction of water do any harm.

Oh, it is wearing out as all engines will do over time. My method will help you figure out how worn your rings really are! Take a compression test before and after and report the results! Steam carbon dispersion of stuck rings will help, but it's not a cure all and just how far if at all your compression comes up will give a good evaluation of how far worn they are. My honest guess is that this will not show much improvement and that a ring job is in your future. Keep us informed!

Greg, the relay will drop the voltage to the plugs after approx. 35 seconds. Therefore, for the remaining 25 seconds, the prechamber will be getting colder.

Far better to glow the plugs for 30 seconds, cycle the key, and glow it for another 30 seconds. Then, you'll get the resulst you are looking for.

The MB FSM says that the glow plugs will continue to get hotter up to one minute.

Care to explain how that might work without voltage applied?

First lets talk about chances...

It is about a 2,000,000 to one chance that it is carbon stuck rings causing this as compared to worn out rings.

For the record, the WAY in which rings wear out is they lose their ability to expand to follow the difference in the diameter of the bore . It is metal fatigue from billions of strokes up and down that cylinder wall.

Using steam to break up carbon buildup INSIDE the combustion chamber on a gas engine is very different from thinking you can reach the rings on a MB diesel engine.....

on the other hand... if you put some liquid into the bore which would act as a solvent for the carbon .. then take it out of the engine before it was run ( ie, not contaminate the oil )... that might have a chance of working IF the carbon stuck rings are the problem.

The idea of proposing to a lay person ( as compared to an automotive testing department) that they take a chance on putting water into the intake.... still crazy in my book.
And warning them not to stall the engine... WHAT method do they have for knowing they are close to stalling it ?
They are taking a chance on breaking a piston or bending a rod trying this on a system as closed and high in compression as a diesel engine.

Care to explain why the MB FSM would say that if it were not true ?

after the 86 model, the GP relay got changed to a model that will glow up to 3 minutes. before that, you only got about 40 seconds.
John

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1987 190D 2.5Turbo
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