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CumminsApart, Cummins Technician
Category: Heavy Equipment
Satisfied Customers: 89
Experience:  Factory trained Cummins Technician- Automotive, Agriculture, Marine and Power generation
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oil pouring out of blowby tube

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all drains clean. oil pressure pegged cold at throttle and 60 idle hot and 90 at throttle hot. ( havent manually verified yet) need new oil pump? anyone seen this yet? 99 frtliner auto trans.also not much blowby from engine
Hi redneck, can you tell me first how many miles are on your engine? Also how much oil are you going through in a day... half a gallon or a gallon or more? Tks Dan
Customer: replied 8 years ago.
ok secound try. 180k or so its a trash truck. i maintain these on a saturday and when needed. im curious about the oil pressure prob. granted this is the reading of onboard guage sofar. pegs guage high rpm cold and hot is 90 psi and 70 idle. the blowby return drains into the return for the turbo. so im thinking too much oil for the retunr for blowby to drain? stuck oil pump relief valve? i can take the oil fill cap off of truck and in gear in drive brakes applied it wont blow the cap out of the hole just resting there. also the truck runs fine and all of those return passages are clear. i checked.ty Later REDNECK
I suggest that you verify your oil pressure with an external gauge. If your in cab gauge is reading right then the relief valve in the oil pump must be stuck. This puts oil up top faster then it can drain back down to the pan. If you need anything else just let me know. Tks Dan
Customer: replied 8 years ago.
ik that. but the problem is its coming out of the blowby tube. its not in the valve cover. and theres no valve cover leaks. im a mechanic of 28 years. theres no galley from the top of the engine to the blowby galley. any more info?
ok I'm with you are you sure that there isn't still a blockage in the turbo drain tube? Does the drain tube bolt onto the side of the block below the turbo similar to a dt466. I had a 466 putting oil out, thought it was a blocked drain tube, pulled the tube out of the block and found the problem hiding in there. It would still allow the oil to get back to the pan but just not fast enough. Maybe you could check that. Let me know if we're on the same page
Customer: replied 8 years ago.
its a little diff fron 466e. it goes strait through. all passages are clear. ive visually verified that. guess im gonna tell them get me a new oil pump.. its all i can think of is thats too much oil goin down turbo return to let blowby return to function properly. ty for the help though
I think your heading the right way sounds like to much oil pressure. If i can help anymore just ask I'll do what i can Tks Dan
Hi There,

It is impossible for the oil pump to just start producing excessive oil pressure! If you have a problem it is not with the oil pump.

The oil pressure relief valve is in the oil cooler/oil filter housing and can easily be accessed. The only way you can get high oil pressure is if the relief valve is stuck shut. If you remove the retaining nut and spring, the valve should fall out under it's own weight, if you have to use anything (ie magnet) to remove the valve this will be the problem. The valve and the housing can be polished with #300 wet and dry, cleaned and reinstalled. If the valve and/or housing are badly scored, you may have to replace them both along with a new spring.

You should check your oil pressure with a known calibrated manual gauge from the main oil gallery, this is the only way you can be sure of the correct pressure.

As for the crankcase breather assembly, your ESN would be needed to see exactly what has been used and how it is plumbed in. Cummins has attempted in the past to use the turbo drain for another return, this failed big time and had to be modified to prevent turbo failure.

You application for this engine can be a problem due to excess idling, but at 180,000 km it is unlikely this would be a problem to consider yet.

If you need further help, please give me an ESN and I can use it to help you further.

Good luck

Customer: replied 8 years ago.
ok the esn 45797235 isc215 8.3 litre and yes the breather assy drains into the turbo return. i will wait on your answer as to any modifications- updates. i will check the relief valv in the oil filter housing as i thought it was a part of the pump. TY Later REDNECK
Hi Redneck,

There doesn't seem to be anything special about your breather assy. The breather assy is only to condense oil vapour out of your crankcase gases and has no relationship with actual engine oil pressure. You can clean the breather from time to time if you suspect it is clogged with sludge, but you will need a new gsk if you take it off.

The return line to the turbo drain should not be a problem because it is so small and the amount of oil returning will be minute. I would be more concerned if you are seeing oil from the main pipe onto the ground.

Just ask if you need anything further.

Good luck

Customer: replied 8 years ago.
yes its going to ground but not much blowby. like i said under load oil cap loose on valve cover it doesnt move. also ive got wear marks on opposite sides of relief valve. new one here tomorrow. ill keep you posted. i think relief vavle binding. if its cured ill accept. hope you dont think im not, because im a mechanic also. Later REDNECK
Hi redneck,

Ok ..... I would check the small return line to the turbo return pipe, check it is clear and clean, it may also have a one way valve in the line, check this is free of sludge or carbon build up. Also clean the breather just to be sure... you can use carby cleaner or similar.

I don't have an ISC block or engine here at present so can't check myself, but if you look along the bottom of the block you may find a small drilling with a expansion plug in it that is for a optional dipstick tube hole, you could remove the expansion plug, grease up a npt tap and tap a thread to take a push on fitting the same size as the breather drain and run the drain to this fitting instead of the turbo drain pipe? It may be the turbo drain oil is being forced into the breather by a badly made fitting?

Re; relief valve. Be sure to polish the valve bore so it won't stick again, and clean it well before assembly. No problem with the 'accept', we are here to help.


CumminsApart, Cummins Technician
Category: Heavy Equipment
Satisfied Customers: 89
Experience: Factory trained Cummins Technician- Automotive, Agriculture, Marine and Power generation
CumminsApart and other Heavy Equipment Specialists are ready to help you
Customer: replied 8 years ago.
sry i forgot but it turned out the turbo was pumpig pressure into crank case. well its a first time for me and ive been doin it 28 years