Engine/Transmission (1998.5 - 2002) Suddenly smoking from breather; positive crankcase pressure HELP!

[KrisKringle]

Today while sitting at a light, I noticed smoke coming from under the hood... turns out that it was coming out of the breather, not just a little, A LOT of vapour. I took the cap off the valve cover, and there seems to be positive pressure in the crankcase, as the cap will 'float' on the cover, and not from vibration either... now I am worried. Checked the oil, and I am about a quart down in 3. 000 miles... truck has around 150. 000 miles...

I installed an 'improved' breather' as seen here: No drip Breather, and am wondering if my 'solution' has too much back-pressure. ( Complete details on the construction are HERE) However, it has been on around a week, and this just started today.

In the meantime, I am going to run a hose to the back of the engine like everyone else...

 

[KrisKringle]

Still Smoking...

Well, it seems that there was too much restriction in the canister I made. I ran a 3/4" hose under the cab, but it still has generating a heck of a lot of vapour... Very strange, the truck runs fine, but I never saw smoke before...

Spent the last hour searching the archives. I need to take a look at the vacuum pump. The rubber elbow that connects from the pump to the hard plastic line is none to sporty if I remember, but I do not remember seeing any splits...

 

[KrisKringle]

Problem Solved..thanks to the Forums

well, today was a heck of a day. Anyway, I managed to stop by my 'second home' at Melchert Automobil, for a coffee and a breather. Speaking of breathers, the truck was sending out smoke signals while I waited at the light in Köln (Cologne). Not something that is good when one is driving an Auto in an 'Environmentally Protected Zone'. (We have stickers on the wind-shield here to designate if an Auto is allowed to drive in one of these areas, and my Dodge will never have one... . ).

Well, with Stefan under the truck, I blocked off the vacuum from the pump, and low and behold, the amount of smoke decreased... well, almost disappeared. .

It turned out (probably from my 15 minute lift-pump changes, that I over taxed the already weak hoses from the vacuum pump to the dash.

Unfortunately, I did not take a picture of the 'Eureka Moment', but here are a few pictures of the results...

Here is the finished repair:

Oh, here is the offending part:

Not really, but really, proof that the solution for the Dodge Ram occurred at Melchert's . . Thanks Stefan...

Anyway, the almost open leak from the vacuum pump was causing the excessive smoking. Thanks TDR, and Melchert AutomobilJonathan.

 

[Vaughn MacKenzie]

I know a disconnected or leaking vacuum line can really cause a lot of blowby vapor, and also causes oil consumption if you keep driving it that way.

 

[kscheffler]

I don't understand how a vacuum leak can cause this? Does the vacuum pump pull a vacuum on the crank case?

 

[B.G. Smith]

I was wondering the same thing. I'm sure someone will let us know but my guess is that the pump discharges into the crankcase so a bad leak would cause a greater air flow into the engine base. bg

 

[KrisKringle]

I was wondering the same thing. I'm sure someone will let us know but my guess is that the pump discharges into the crankcase so a bad leak would cause a greater air flow into the engine base. bg

That's right. If you look behind the pump, there is a braided line that goes to the crankcase, that is the oil feed. However, FWIU, the exhaust from the pump goes into the crankcase, I guess with the 'drain' oil? Normally the system is 'closed. ' When there is a vacuum leak, all of the 'exhaust' from the pump ends up in the crankcase, adding to the volume of air already being displaced by the descending pistons... increasing oil consumption, as well as blowing a ton of air and oil out of the breather... HTH Jonathan

 

[EForbes]

I will check that out, mine started all of a sudden a week ago when i towed my 5er on a 200 mile trip, all flat, got home and was putting it away, and as i was idling to disconnect trailer, there was smoke flowing from under the truck, i thought thats it, she is blown with 169k on the clock. i tried the switching from defrost to floor to vent and it worked, but may not be an accurate way to check vacuum pump.



, thanks for the info.

 

[Dieseldemon]

That braided line has oil presure to lube the vacuum pump right off the oil galley the drain is in the front into the gear hsg

 

[EForbes]

I got a closer look at my lines and mine was exactly the same. i replaced it, and it does seem to be alot less smoke, i guess it was leaking although i could still change from floor to defrost etc. seems to switch quicker.

 

[KrisKringle]

I will check that out, mine started all of a sudden a week ago when i towed my 5er on a 200 mile trip, all flat, got home and was putting it away, and as i was idling to disconnect trailer, there was smoke flowing from under the truck, i thought thats it, she is blown with 169k on the clock. i tried the switching from defrost to floor to vent and it worked, but may not be an accurate way to check vacuum pump.

, thanks for the info.

Even with a leak in the lines, the pump can supply enough vacuum for the controls to work... I thought the same thing. I hammered on the truck with about 2 tons of roll-roofing in the bed... hills and curves, and a lot of shifting gears. Suddenly there was smoke from under the hood from my 'no-drip' breather. Oh, yeah, and oil everywhere...

 

[EForbes]

Even with a leak in the lines, the pump can supply enough vacuum for the controls to work... I thought the same thing. I hammered on the truck with about 2 tons of roll-roofing in the bed... hills and curves, and a lot of shifting gears. Suddenly there was smoke from under the hood from my 'no-drip' breather. Oh, yeah, and oil everywhere...

Thanks again, there was noticeablly less smoke last night, i will take it on a drive later on after work, and i will be very happy im sure.

 

[KrisKringle]

Looking for rubber elbow for vacuum line...

Wow...did a google search, and ended up back here...5 years later. I am trying to find the rubber "elbow" shown in the following picture. I have spent the last hour combing through the parts book trying to find a PN. (The picture BTW is one I found on another forum; I was too lazy to go out and take a picture)

So anyone have an Idea what the PN is?

thanks...Jonathan

 

[BoeingDiesel]

Jonathan, check this link. You may not find an exact replacement but you can modify to solve the issue
http://www.dormanproducts.com/c-748-vacuum-tubing-connectors-soft.aspx

 

[BigPapa]

This thread contains some info that may be helpful:


https://www.turbodieselregister.com/threads/255520-Part-for-fitting-on-Vacuum-pump


As stated in that thread the rubber part doesn't have to be an elbow. I had listed a Dorman part number there that may work for you.

 

[KrisKringle]

Thanks...I got to looking at the thing, and wondered if it is a standard vacuum fitting. I guess I will have to ask at the parts house if they have a "Gummiunterdrückleitungbogen"...jeepers Germany. Thanks again.