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Robert R
Robert R, ASE Certified Master
Category: Dodge
Satisfied Customers: 4406
Experience:  Dodge Master Certified, Dodge Sprinter Certified
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I have an old 96 12 valve with lots of little issues,

Customer Question

I have an old 96 12 valve with lots of little issues, however most worrisome right now is collection of small oil leaks and recently a very bad leak(s) oil blowing out of breather tube and dip stick really large amount. also fair amount of white smoke out of breather as well. Truck seems to still have plenty of power. read online how a vacumn leak can pressurize the crankcase....not sure how this works but saw on Diesel Bombers or some such.
I think i have a small leak from vacumn pump/power steering which seems to be pretty common and I already have the repair kit. Also perhaps small leaks at front crankcase seal and perhaps rear main seal but again the really BIG leak is out of breather tube along with fair amounts of whitish smoke
Submitted: 1 year ago.
Category: Dodge
Customer: replied 1 year ago.
Also thought I should mention I bought the truck used and odometer currently reads 210,000 miles....however the GPS I use shows the speedometer and odometer off by about 15% (not sure why) in otherwords could be closer to 250,000 miles. Also truck starts right up and can go 80 + mph on the highway with relative ease and otherwise seems to have lots of power. The big leak problem is relatively new...I used to add a quart every week or two but have been living with this problem for a couple of weeks now and adding a couple of quarts a day (50-100 miles)
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

On some engines the crank case has a vent to where the pressure is vented usually back into the engine and if the venting system is clogged or damaged at all this will cause pressure build up in the crank case that will cause oil leaks and sometimes smoke to occur.I would check over the engine for any venting tubes or breathers and see if any are collapsed or damaged in any way needing repaired or replaced at all.If these are all checked and found to be o.k. let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
Pete, please double check what I wrote above. I need a more specific answer than what you hae given me This is a 1996 Dodge Cummins Diesel that relatively recently began to blow large amounts of oil out of dip stick and out of breather tube. I am pretty sure the breather tube is not bent or blocked because oil is being thrown out of it along with a fair amount of light white smoke. I pulled the dip stick itself and jury rigged a tube from it to the oil filler cap so the oil that was coming out of the dip stick tube is now going back into the crankcase, but I am still losing lots of oil out of breather tube. I have some other small leaks that used to amount to a quart or so every couple of weeks, but I am now having to add a couple of quarts per 100 miles or so. There are several diesel discussion forums and they address this problem saying it could be blow by from older worn engine...( but engine has lots of power) OR they talk of somehow a vacumn leak causing the vacumn pump to pressurize the crankcase. If you google "Dodge Ram Diesel Oil out of breather tube" or Dodge Ram Diesel Oil out of dipstick tube" you will see what I mean
Expert:  Pete replied 1 year ago.

Unfortunately this is all of the info I have on this here myself.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Expert:  Robert R replied 1 year ago.

Hello, welcome and thanks for asking your question. My name is*****'m a Certified Auto Technician with 28+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.

I'm a fully experienced Dodge Technician that has worked on the Cummins engines in Dodge Trucks since day one. I was around when the first Cummins equipped Dodge Trucks were delivered back in 1989....

I myself have NEVER ran across an issue where the vacuum pump can pressurize the crankcase. I have seen vacuum pump seals fail many times and cause a very large leak to be generated at the point where the vacuum pump meets the power steering pump but in each case, the crankcase was not pressurized. In these cases, rebuilding or replacing the vacuum pump solved this issue.

As for what you are describing, it sounds like a classic case of excessive crankcase pressure buildup due to excessive blowby. Just because there is excessive blowby doesn't mean that the engine won't have plenty of power. Many times I worked on vehicles with this condition, there was never any mention of the customer complaining about a loss of power. The only concern was about large oil leaks and oil consumption. Sometimes, there is a clue upon initial starting of the engine in the morning during a cold start. I have seen many times where upon initial starting, the engine runs rough for 30 seconds or more and much white smoke out the exhaust. This is a clue that there may not be enough compression for complete burning of the fuel. Once the engine begins to warm, these symptoms clear quickly.

I have an easy way for you to check for yourself if there is excessive blowby caused by a worn engine.

When you start the engine for the first time, pull the oil fill cap before starting the engine and leave it off. Start the engine and let it idle. Look for puffs of smoke billowing out the oil fill cap. If you see much smoke and puffing up through the oil fill cap, this is a sure sign that there is excessive blowby caused by one or more failed cylinders.

This could be caused by "Dusting of the engine" which can be caused by poor air filter replacement intervals, or the use of aftermarket filters of inferior quality or the use of many of the K&N style air filters that are not properly maintained. Could also be that some piston compression rings have broken and caused loss of compression this way.

Keep in mind that the5.9 diesel is a fairly powerful engine, many times with this type of failure, you may or may not notice a considerable amount of power loss when problems like this arise.

if it is possible that you can make a video recording of you performing a "Cold Start" while recording the engine idling with the oil fill cap removed, I may be able to confirm that there is in fact excessive blowby caused by one or more cylinders...

Keep me posted...

Thank you,


Customer: replied 1 year ago.
The bad oil leak turned out to be (believe it or not) a vacuum leak just like the info I stumbled across online! When I traced the vacuum lines, I found that the elbow near where the small vacuum line goes through the firewall, had been touching the turbo and had melted enough where it leaked. I temporarily wrapped it in duct tape until I could get the fitting and the leak and smoke coming out of dip stick and breather tube stopped immediately. Also have checked oil last three days and it is holding steady. I appreciate your attempt at answering my problem but your information was not the answer that fixed it so I do not know how to proceed.