Author Topic: Oil consumption/loss-3126B  (Read 5541 times)

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Offline laurasr57

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Oil consumption/loss-3126B
« on: July 26, 2016, 02:06:17 PM »
Have a 2000 3126B, approx 85000 miles, engine is using oil, but shows no leaks or signs of burning oil from exhaust. Have read of issues with some 3126B's having mysterious oil loss that was found to be defective 0 ring on injector, causing oil leakage into fuel and burned with fuel.
Has anyone had this issue? If so how was diagnosed, and approx cost to repair.
Any help would be appreciated.
Thanks Wayne

Offline Brett Wolfe

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Re: Oil consumption/loss-3126B
« Reply #1 on: July 26, 2016, 03:01:53 PM »
Wayne,

First question:  Have you calibrated your engine oil dipstick?  Since your chassis maker, NOT Caterpillar supplied it, it is quite possible that it is not properly marked.

And, were you to overfill the crankcase by, say 2 quarts, that would very quickly come out the crankcase breather tube.

You can also verify your correct oil volume either by calling the Caterpillar RV Hotline with your engine serial number OR post you engine serial number here and we can look it up for you.

Brett

Offline David.e.atherton

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Re: Oil consumption/loss-3126B
« Reply #2 on: July 26, 2016, 06:17:56 PM »
Laurasr57, using oil 3126b. As Brett mentioned know where oil is showing on dip stick, there is
 Few suggestions loss of oil within system. O-ring on injectors would rule that out because you
making oil instead of loosing oil ( cut open your secondary fuel filter 1R-0751 and paper inside
Black from engine oil ). Engine blowby tube plugged will cause oil to exit engine via: dip stick
and worse cases front or rear engine crank seal. The place I would look is at your air compressor,
unloader valve letting engine oil into air wet tank or broken rings on air compressor. Last place
to look, remove rubber boot fro air filter to intake or cold side of turbo charger seals or bearing bad.
That is easy to check you will see oil in the compressor blades and oil being pushed out into intake
tube. Turning compressor blade there will be movement but if you can deflect compressor blade
to rub on turbo housing housing your turbo is bad. Dave Atherton Retired Cat Mechanic



Offline laurasr57

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Re: Oil consumption/loss-3126B
« Reply #3 on: July 26, 2016, 06:50:28 PM »
Thanks Brett and David
Brett,- Yes I have calibrated the dip stick and it is right.
David,- I do my own maintenance, not sure if that's good or bad, but I have crawled all over the motor and no signs of leaks anywhere. The oil loss is significant , quart/150 miles, power and fuel mileage have stayed the same,
Not sure I understand, on ruling out 0 ring, if oil is being pumped out of oil system, into fuel system and burned would'nt I be losing oil.
I will cut open secondary fuel filter and check for black from engine oil, also check compressor and turbo.
Thanks again to you both for your suggestions, I appreciate any info.
Wayne

But any info would be appreciated
Thanks Wayne

Offline David.e.atherton

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Re: Oil consumption/loss-3126B
« Reply #4 on: July 27, 2016, 12:00:38 PM »
Wayne, if you have a oil usage the amount that you telling us than your engine oil level is
Increasing. The injector cannot possible be leaking engine oil past o-ring or o-rings to be
burned by the injectors. Also note: with HEUI injection system oil leakage passed the injector
Is normal up to 4 %. Could have crack in copper sleeve that's holds injector in place that will
allow engine oil into cooling system or engine oil cooler o-ring letting oil into cooling system.
There has to be more formation that is lacking here. Exhaust smoke, inside of exhaust pipe,
last post indicated turbo seal leaking oil to the compressor side and being retained in CAC.
But we are lacking smoke or heating should be added to problem someplace.
Dave Atherton Retired Cat Mechanic

Offline laurasr57

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Re: Oil consumption/loss-3126B
« Reply #5 on: July 27, 2016, 12:49:18 PM »
Thanks for reply Dave.
Here is one of the internet posts tha leads me to belive it is an 0 ring.I found a few others that had seen this problem, but not many.

https://www.reddit.com/r/Justrolledintotheshop/comments/1v47r0/cat_3126_mysterious_oil_consumption/

As I said in previous post power and mileage are normal, and no overheating or issues seen on my Silverleaf moniter., also see no signs of oil in coolant.
Thanks again for your patience and trouble, appreciate any input.
Wayne

Offline David.e.atherton

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Re: Oil consumption/loss-3126B
« Reply #6 on: July 28, 2016, 10:40:06 AM »
Wayne, the Internet is a great tool for engine problems but can be your worse tool  if
Information cannot be backed up with caterpillar technical information which is dealer
only.  Information that I'm posting can be backed up with caterpillar technical information.
SMCS code: 7569

Let's go back to o-ring at injectors. ( fuel leakage into the engine oil via: injector o-ring )
will cause high fuel consumption  and low engine oil pressure. This condition will also increase
The oil level in crankcase. Incorrect engine oil. Review engine oil change intervals.

SMCS code: 1348-040  Excessive Engine Oil Consumption no leakage to outside engine

Oil leakage into Combustion area of cylinders will cause blue smoke. There are four ways
Oil leakage into cylinders: oil leakage between worn valve guides and valve stems.  Worn
components or damage components , pistons , piston rings or dirty oil return holes ( oil
sludge buildup ), broken piston rings), worn intermediate oil ring or compression ring.

This I mention earlier, oil leakage past seal ring in the impeller end of turbo shaft

Excessive oil consumption can also be the result if oil with the wrong viscosity is used. Oil
with a thin viscosity can be caused by fuel leakage into the crankcase or by increased
engine temperature. Again this information can be found with Caterpillar tech information.
Dave Atherton Retired Cat Mechanic

Offline laurasr57

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Re: Oil consumption/loss-3126B
« Reply #7 on: July 28, 2016, 04:43:05 PM »
Thanks for reply David:
I realize the interenet can steer me wrong, but as I stated I try to do all my own maintenance.
I don't have access to Cat's tech info, unless I want to pay the bill, and that is always a last resort, so I rely on the internet for most info.
What I find strange is the coach runs as normal in every aspect, except it uses excessive oil.
I have drained and changed oil since this began, and was only able to drain 7 quarts out of crank, in fact engine shut down due to low oil pressure. After adding 19 quarts engine restarted and ran fine.
I realize this may be hard problem to diagnose, and appreciate any tips.
I am not currently at the coach so can't do anything very soon.
Thanks again for your time and trouble to respond.
Wayne