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Old 02-27-2003, 12:34 AM
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Join Date: Sep 2002
Location: Utah
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Woke up the sleeping 240D..on 3 cylinders..suggestions?

I posted earlier about waking up a 240d that has been sitting for a year or so.
240D cracked manifold?? ( pictures)
I followed your suggestions and she lit up on que, however as stated in my earlier post I am worried about several things and hope the board might be able to help.
I have a cracked ( 2 places see pic) exhaust manifold and the possibility that the previous owner over heated the engine and maybe blew a head gasket. The car started up fine and built rpms but only the last 3 cylinders are firing.
I did a compression test and a leakdown test .
The leakdown test was done on the#1 leaky cylinder and the input air was set at 65 lbs. and the amount of air holding back in the piston was 45lbs. so 20 lbs of air or approx 30% was leaking. I could not hear air at the exhaust or intake.. only coming out of the valve cover/crankcase.

The compression test showed the following

#1 cylinder....175 lbs
#2 cylinder.....240 lbs
#3 cylinder.....285 lbs
#4 cylinder.....285 lbs
Adjusting for my elevation (5,000ft) and the fact I had to use so many adapters to take the compression I will say the values for each read is probably 10% higher than posted.
My question is where to go from here.??
Could I have stuck rings in numer 1 and try the rislone treatment?
Should I try the diesel purge..not that that would solve any cylinder problem.
Should I go ahead and pull the head.. I really don't know if the engine was overheated .
Should I throw in some new rings and bearings? Guess I'm stubborn and still looking for the simple solution. Maybe just a head gasket problem?? Could not tell from the leakdown test.
Anyway.. any thoughts or suggestions appreciated..
What would you do next?
Correction on the mileage+ 160k total..

* PS ..4 cylinders are sure nice to work on..: ) lots of room!!


Last edited by bennett; 02-27-2003 at 01:14 AM.
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Old 02-27-2003, 06:37 AM
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The air sound coming from the oil filler while doing leakdown indicates cylinder/piston/ring problems. It could indeed be a stuck ring, but I see this as unlikely. It is, however, worth pursuing.

Is there any coolant in the oil, or oil in the coolant? I would be surprised if there is any head or head gasket problem from overheating. These heads are big, solid and cast iron. If there is no coolant in oil or vice versa, then you might try the following.

Using some sort of magic medicine for freeing stuck rings should be approached with caution. A diesel engine has very small combustion chambers, so there is not room for much uncompressible liquid. I would pull the injectors and squirt plenty of Marvel Mystery Oil in the number one cylinder and let it sit overnight. The next morning, turn over the engine until it is no longer blowing oil out of the injector hole. Because of the prechamber, it will be hard to get the oil in and out, so MAKE SURE all oil is out. Then put in your injectors, bleed and start.

I think this is worth a try.

Good luck,
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Old 02-27-2003, 01:28 PM
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Join Date: Sep 2001
Location: central Texas
Posts: 17,277
Your statement about not being able to tell anything from your leak down test is correct....
I think you should put 100 psi into the cylinder to start the test... this is still only about 50 percent of working pressure...
The pressure is going to equalize with the outside air pressure at some point... this is why it is called a " leak down" test instead of a " does it leak" test.... so YOU MUST TIME THE LEAKAGE RATE in my opinion to have any useful information.... and unless you can find some information about the speed it should leak... you are really just finding a base line for future leak down tests of your engine...I hope you can find some figures as to what it should be because the leak down test is a good test....
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Old 02-27-2003, 01:50 PM
Diesel Power
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The leakdown tester that I have works between 80 and 100 PSI. The guage works in the following manner:

Set up regulator at the compressor to between 80 and 100 PSI.

Adjust regulator on leak down tester to set the needle to zero.

Attach outlet hose to injector or glow plug hole (whichever adapter is supplied). Attach outlet hose to tester. Where the needle moves to, indicates percentage of blowby. The limit for most engines is 20%
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Old 02-27-2003, 01:58 PM
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Location: Utah
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Thansk for the suggestions..

Larry B=There is no oil in the coolant or visa-versa.

Leathrmang= I will do another leakdown test today at 100PSI.

Couple questions for anyone that can help.

1. What is the compression supposed to be on a240D with 160K?

2. What on earth would cause that exhaust manifold to crack in 2 places? That's the smoking gun question.. ( pun intended)
I must be overlooking something?? could the PO used ether and cracked them or would the head go sailing?

3. FYI- I have swapped injectors to different cylinders and still #1 does not fire. That should mean the Injection Pump is OK?

Thanks again.. hope I don'twear out my welcome.

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Old 02-27-2003, 09:53 PM
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Location: Utah
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[QUOTE]Originally posted by leathermang
[B]Your statement about not being able to tell anything from your leak down test is correct....
I think you should put 100 psi into the cylinder to start the test... this is still only about 50 percent of working pressure...

Ok ..guys I re-did the leakdown test on number1 cylinder and here is what I found.

100lbs of air in at TDC on compression.. and got about 90-95 lbs. pressure out..only a 5 lbs drop..GOOD!!
What I did diffrent is clean the grime off the balancer and put it right on TDC. Now I am really confused??
should I try the leakdown on the whole cylinder as I rotate under the compression stroke?
Please feel free to make suggestions..


Last edited by bennett; 02-27-2003 at 10:21 PM.
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Old 02-27-2003, 10:48 PM
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Join Date: Aug 2001
Location: Northern Virginia
Posts: 2,911
Yes, I think you should continue to apply air pressure while turning the cylinder through the entire compression stroke. It should tell you something - either that you are not leaking all that much, or that the cylinder wall has some kind of gouge.

Not all that likely to have a gouge in the cylinder wall, but possible I suppose.

The cause of your miss might also be a clogged up prechamber, filled with carbon. Or the injector not injecting fuel in that cylinder.

At some point your testing might include swapping injectors to make sure it's not a bad injector on that cylinder - but I don't think you're there yet.

Have you adjusted the valves? This is very important. You don't seem to have any indications that valves are a problem - but a valve adjustment is a free confidence check.

I would think that with compression a little low on one cylinder, you would get uneven running and some smoke. Wouldn't the fuel partially ignite enough to smoke?

You want to exhaust all the possible "easy-to-solve" issues like fuel delivery before you start to tear into the engine.

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Old 02-27-2003, 11:50 PM
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Location: NE Okla
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How clean is the engine compartment of this car? Is is possible that someone (PO) attempted to clean the engine and engine compartment with a hot engine and manfold? Sounds kinda stupid, but might have caused the manifold cracks.
1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150
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Old 02-28-2003, 12:23 AM
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Location: central Texas
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Please read my cautions in this thread....

Leakdown Tester and ?'s
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Old 02-28-2003, 12:35 AM
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Since you swapped the injectors, they are probably OK, but that doesn't mean you IP is getting fuel thru the line to #1. Crack the line at the injector and see if spews diesel. (As per your second post, question #3).
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)
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