2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

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2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

November 18, 2022, 11:25:26 am

Just hit 150K miles and have 2 unrelated engine problems:

Exhaust manifold is leaking at its junctions (not at the exhaust ports). Repairable or replacement?

Excess oil leakage from the bypass tube. One shop is telling me there a screen/filter under the valve cover that can fail and cause the leak. Simple matter to remove the cover and verify.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #1 – November 18, 2022, 12:29:22 pm

I have had the oil by-pass problem occur several times in the last 10 years. I have done two things that seem to help:

1. I first extended the tube into a tin can I attached to the lower frame with some hose clamps. You want to make sure the hose is high enough in the can that it does not get blocked but does catch the drips. This keeps the oil from blowing around as it drips off the tube and making a mess.

2. I also found out that if I only fill the oil to halfway between the full and add lines (it's 4 qts between them), it significantly reduces the problem. Have never been told about a screen/filter under the valve cover. Would be interested in knowing if there is one.

Rich

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #2 – November 18, 2022, 03:17:38 pm

Maybe you have the wrong dipstick and when it's full you have to much oil in the engine.
Next time you do a service check if the right amount of oil is in the engine.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #3 – November 18, 2022, 04:25:06 pm

Oil to fill seems to be OK.

Rich

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #4 – November 19, 2022, 08:37:44 am

Quote from: Larry Rubin – November 18, 2022, 11:25:26 am

Just hit 150K miles and have 2 unrelated engine problems:

Excess oil leakage from the bypass tube. One shop is telling me there a screen/filter under the valve cover that can fail and cause the leak. Simple matter to remove the cover and verify.

150K miles is a walk in the park for these engines, but remove the oil filler cap and hold a piece of paper over the opening and see which way the wind blows and how fiercely.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #5 – November 19, 2022, 10:09:40 am

Not to imply that you would Larry but don't let a shop recommend a overhaul based solely from a bit of drip from the crank case breather tube. Possible that the engine could need piston rings but more unlikely. Many diesel's will experience slobber from the tube . Rich mentioned one way and I will add another. Like Rich said, be sure your tube/hose is long enough to reach to about half way down the side of the oil pan then use one of the more sturdy plastic water bottles, take some steel wool and maybe a piece of paper towel and place it in the bottom of the bottle. Take a heavier version of a zip tie and run it thru a couple slits cut in the upper part of the bottle. It should be relatively easy to find something in the area to secure the bottle to with the zip tie. Dump it out a couple times a year. Monitor your engine oil use with the dip stick. This will keep any spatter of oil drops off your tow and keep it off your engine and engine room hatch as well. You may find Rich's method as easy but you have a choice. Again be sure the hose doesn't reach the bottom of whatever catch devise you decide to use.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #6 – November 19, 2022, 10:21:29 am

I like to run my slobber tubes uphill to separate the air from the oil a little .

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #7 – November 19, 2022, 10:30:44 am

Will add, I've never known of a screen stopped up under the valve cover associated with a breather tube. Not saying there has never been, just saying I've never been told of one or seen one in my trucking years but I'm sure I've missed some things along the way. There were some years that Cummins ISX used an external crank case breather but it is mounted on the outside of the engine toward the front.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #8 – November 19, 2022, 11:07:27 am

Quote from: Larry Rubin – November 18, 2022, 11:25:26 am

Just hit 150K miles and have 2 unrelated engine problems:

Exhaust manifold is leaking at its junctions (not at the exhaust ports). Repairable or replacement?

Is it even notable? If it is leaking bad enough to cause damage yes replace it. If its leaking and not affecting anything I would consider this normal. Its not like your going to run out. I have seen the slip joints on exhaust systems wear out but it was after many overhaul lifes. Not during the original engine life. If you were to replace a serviceable manifold with a new replacement you may even notice larger tolerances . Without hands on viewing it is difficult to say or speculate.
Scott

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #9 – November 19, 2022, 12:38:58 pm

Will add to what Rich and I mentioned about "catch cans" , it will also keep oil from being drawn into the radiator fins where it will gather and hold dust and you know the outcome of that over a period of time.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #10 – November 19, 2022, 12:47:07 pm

Quote from: Dub – November 19, 2022, 12:38:58 pm

Will add to what Rich and I mentioned about "catch cans" , it will also keep oil from being drawn into the radiator fins where it will gather and hold dust and you know the outcome of that over a period of time.

While I am also a big fan of a "catch can" (actually I use a clear plastic bottle so I can see what is happening) with a side radiator, I wouldn't be too concerned about oil/oil vapor being sucked into the cooling package, as air flows from the outside to the inside.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #11 – November 19, 2022, 05:52:48 pm

Thanks for all the ideas ---- I will put a bottle on the "slobber tube" (love the name) and see how much it leaks. The truck repair shop I trust is going to take a peak under the valve cover to see if there is anything amiss.

The exhaust leak definitely needs to be fixed. I was getting some exhaust smell in the bedroom and then much more after a short trip. Lots of soot on side of valve cover and major bubbles when spray manifold collars.

Is there any way to reseat the manifold or does it have to be replaced?

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #12 – November 19, 2022, 06:22:06 pm

Larry,

We need to know exactly where it is leaking.

A picture would be great.

As has already been mentioned, overfilling the crankcase with oil is the #1 cause of "slobber". Before spending too much time/$$, make sure it is not overfilled.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #13 – November 19, 2022, 09:05:30 pm

Quote from: Larry Rubin – November 19, 2022, 05:52:48 pm

Thanks for all the ideas ---- I will put a bottle on the "slobber tube" (love the name) and see how much it leaks.

We have two motorcycles one each from 1983 and 1986 with what we call "Spooge Tanks." Honda lists them on the maintenance schedule to be drained. They collect the oil and water from the crankcase breather tube.

The '62 Studebaker has a traditional crank case breather tube with one-way reed valve so the air is always moving out.

The '68 Siata has this complicated arrangement so the crankcase vent goes to the air cleaner where the vapors run back through the engine and the liquid drains down to a throttle operated valve to be consumed at large throttle opening: Italy's answer to positive crankcase ventilation.

Once upon a time, maybe before you were born, the center of the lane on our highways and secondary roads was coated with a layer of oil and dirt from road draft tubes that became slicker'n snot in the rain. With the introduction of positive crankcase ventilation I was amazed at the speed with which these death traps dissolved and disappeared with weather and traffic.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #14 – November 20, 2022, 07:16:46 am

Quote

We need to know exactly where it is leaking.

A picture would be great.

As has already been mentioned, overfilling the crankcase with oil is the #1 cause of "slobber". Before spending too much time/$$, make sure it is not overfilled.

The exhaust is leaking from the manifold joints and its significant. The oil is coming from the slobber tube. Not sure how more precise I can get.

The oil leak started months after an oil change and no oil had been added.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #15 – November 20, 2022, 08:47:38 am

Larry,

Is the oil level higher on the dipstick than it normally is/before oil change? Again, if overfilled, what you see is absolutely normal. An engine will "puke" oil until it reaches its normal level. Caterpillar, as well as Cummins went through this and ended up reducing the recommended quantity of oil by one quart.

On the exhaust manifold, I assume you are referring to the slip joint between the halves of the manifold rather than head to manifold or manifold to turbo. That is an unusual location for a leak on that manifold. Not aware of any solution other than replacement. Have the two sections separated? Is there are crack?

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #16 – November 20, 2022, 10:30:06 am

Re: oil
Confusing thing about the oil is that it did not leak immediately after last change. Never happened before and I know previous changes filled it up to the full mark. It happened during long multiday trip (over 1,000 miles). Engine did not overheat - everything seemed normal. It was down on the dip stick because. I assume, of the leak.

I just had the oil changed and will check if they filled it to mark. I will attach the the can to determine if leaks more.

Re: manifold
Quick look so far don't see any cracks or changes in position - only bubbles at slip joints - not at head or turbo connections.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #17 – November 20, 2022, 10:33:39 am

My puking has happened several times, even after I stopped filling above the 1/2 line. Then it clears up. Can't say why but so far no engine problems associated with it.

Rich

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #18 – November 20, 2022, 10:36:39 am

Quote from: Larry Rubin – November 20, 2022, 10:30:06 am

Re: manifold
Quick look so far don't see any cracks or changes in position - only bubbles at slip joints - not at head or turbo connections.

The slip joints would not be air tight until carbon builds up in them.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #19 – November 20, 2022, 11:12:19 am

What does Cummins say about the venting?

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #20 – November 20, 2022, 08:14:51 pm

Quote

The slip joints would not be air tight until carbon builds up in them.

OK - does that have any impact on leaking on there own after years of use?

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #21 – November 20, 2022, 08:22:09 pm

If the joints have worn down, replacement would be the only cure. Haven't had it happen on diesel engines I have owned for 40 years. I usually have a very hard time separating them because of carbon build up. My Cat 3306 had slip rings. Don't know about our Cummins.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #22 – November 21, 2022, 01:02:18 pm

Quote

What does Cummins say about the venting?

They say the gaskets could be the problem or manifold can be warped/cracked and "yes it does happen".

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #23 – November 21, 2022, 06:18:46 pm

Sorry I meant the bypass tube.

Re: 2 unrelated problems on 2004 ISL: exhaust leak, excess oil from oil bypass

Reply #24 – November 21, 2022, 11:30:40 pm

Re: the exhaust manifold leak. Warped and cracked manifolds on that engine are not uncommon. Mine warped and was leaking exhaust gas. Pulled it, machined it, re-gasketed and no problems since. 3 years now.

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