Engine/Transmission (1994 - 1998) engine issue

[CBrabec]

So i took my truck to a local great plains cummins shop to have them run some tests to see why i was suddenly having oil leaks popping up all over. So they steam cleaned the motor off and then put in a tracer dye to see what areas were leaking. They called me and asked if the could preform a blow by test and I said yes. They called me the next day and said that my blow by # got to 36lbs and they had to stop the test before the pressure blew the water out of the gauge. Anyway they told me that because of this # that my compression was low and that the only way to fix this is to rebuild the motor and have the cylinders bored out and install new pistons, rings seals at a cost of about $9-10K. They said they wouldn't recommend fixing the leaks because they would eventually blow the seals out again because of the extreme pressure from the blow by and it blows out the seals to release the pressure. Now the truck runs strong, no loss in power, no engine knocking, no excessive smoke, idles smooth, no leaking oil at the head. Now they told me because of the high blow by that my compression was low which is a major cause of my poor fuel mileage (ave. 11.4mpg) Does anyone have any ideas as to what's going on before I decide to pay to have the motor pulled? I'm stumped

Chris

 

[Joseph Donnelly]

How many miles on the engine? Stock air filter or oiled element aftermarket? If the ring seal is going away due to ingesting dust over a lot of miles, you do need a rebuild. You may find a shop to do a good job cheaper than that.

 

[moparguy]

I bought a 98 12V a few years ago with washed out rings due to a bad air filter seal and a life on dirt farm roads. The blow-by didn't manifest in leaking gaskets so much as a lot of oil blowby out the road-draft tube. Are you seeing oil blowing out/dripping from that tube?

If not, I'd add oil when needed, clean the engine occasionally and drive on. Also on the 98 fuel mileage wasn't bad, but it was using a quart of oil per 100 miles.

 

[fest3er]

Replace the oil filler cap with some PVC tubing to direct the excess crankcase gases downward. I did this nigh on 10 years ago on my '98 12V after seeing oil everywhere and using a quart every 500 miles. After relieving the crankcase pressure, oil consumption returned to a quart every 2500 miles or so. 100k-150k miles later I still get 19-20 MPG, good power, and reasonable oil consumption.

When crankcase pressure builds up enough, oil cannot flow back to the pan and finds other ways out.

 

[moparguy]

Fest3er, that is a great idea. I like it!

 

[hsmith]

The Case valve covers with the breather also work well.

 

[CBrabec]

Thanks guys for everything. The truck has about 238K miles on it and yes I did buy it from a farmer who was the original owner and the truck saw dirt roads its entire life up until about 2 years ago when I bought it. This truck was in immaculate shape when I bought the truck both interior and exterior wise and I looked for all the major problems areas I could see exterior wise on the motor before I bought it. I replaced the OEM air box with an AFE stage 2 w/ a pro guard 7 filter about a year ago. Most of my oil leaks are coming from the front crank case seal that's blown out, the oil tube coming from behind the P pump, the vacuum pump is leaking where it connects to the power steering pump, the bottom of the oil tube that connects to the turbo and # 5 and 6 valve cover gaskets were leaking. I drove the truck yesterday and got it all nice and warmed up and when I got home I took off the oil fill cap to check for smoke and there was nothing. The shop said if I had bad rings or cylinder damage I would see smoke coming out like a train. I don't get much blow by out the tube at the bottom and the weird thing is my truck doesn't burn hardly any oil. I maybe a 1/2 qt low if that before I do my oil changes every 3500 miles. I'm still stumped as to why my blow by #'s are this high but the truck doesn't drive like its got major internal damage!

Chris

 

[DonFitzwater]

I suspect one of two possibilities for your high leak down numbers. 1.tech didn't know what he was doing OR 2. It may be time for a valve job. Did they tell you if the leak down test showed leakage into the crankcase, intake or exhaust? I'd lean heavily towards your engine only needing a head rebuild. Worn valve guides at that mileage aren't uncommon.......if it actually failed a leak down test.

Fix the leaks and drive on!

 

[crabman]

There is a excellent video on YouTube on how to replace the O-rings in the vacuum pump & P/S.
http://www.youtube.com/watch?v=vJhR48a-9R8
Dodge Diesel 2 Section vacuum pump repair 1996-2002

 

[GAmes]

Most of my oil leaks are coming from the front crank case seal that's blown out, the oil tube coming from behind the P pump, the vacuum pump is leaking where it connects to the power steering pump, the bottom of the oil tube that connects to the turbo and # 5 and 6 valve cover gaskets were leaking............ stumped as to why my blow by #'s are this high but the truck doesn't drive like its got major internal damage!

The crank front seal, the vac pump/ps pump seal and the valve cover gaskets are fairly easy repairs. If you have never checked the KDP, replacing the crank seal in conjuction would be a good plan, and do it soon. The oil tube from the turbo probably only needs to have the clamps tightened. The oil tube behind the p-pump is the crankcase vent tube, and that is where blowby is measured. If the "tech" used the wrong orifice in the manometer during his test the results would be skewed. At least 90% of the repairs I have had to do on my engines is replacing gaskets and seals (other than the rebuild at 800k). One of our members observed that the Cummins doesn't leak oil, it sweats horsepower.

 

[hsmith]

And the most time consuming gasket replacement is the side cover as the p-pump has to come off. I am not looking forward to replacing mine and the oil pan as well.

 

[GAmes]

And the most time consuming gasket replacement is the side cover as the p-pump has to come off. I am not looking forward to replacing mine and the oil pan as well.

Nothin' to it but to do it Smitty. :-laf

 

[fest3er]

Nothin' to it but to do it Smitty. :-laf

"Do. Or do not. There is no try."