Dipstick pops out

[Rikadoo]

So as the header states i have a engine on a 2005 HR Navigator with a lsm cummins, the customer has replaced the dipstick cause it pops out of it receptical, the only way to keep it in place is to tie strap it. Looking at the engine it has a draft tube, however looking at the cummins on line insite it shows for that ESN it should have a external filter to capture oil vapor. When i try to search for valve cover to see if possably there may be a screen or ? Inside to capture vapor its not even shown. Have tried on line to gather info on the ez handle may have a issue or if there is something in the valve cover is not turning up much. I know whith Ford when we had a suspected vehicle with excessive blo by we had a procedure using a monometer and plug. My question is there any dipstick upgrades or blo by tests or???

[Benjamin]

Remove the vent hose and make sure it's clear. They can plug up with dirt on the bottom end, or gunk and rust on the top end, hopefully not.  If the vent tube is clear, and it's not using oil, then I'd suspect something funny is happening with the movement of the extra long dipstick tube causing the dipstick to work out.

[Johnny Mo]

On my 2009 ISM, the dipstick had a rubber boot that would expand by turning/tightening the handle on the end of the dipstick.

If that is type you have, replace the grommet. I got one from a local truck parts store. It too would not stay in…

My 2007 ISX the dipstick has a plastic lock

[Ivan K]

I have had the dipstick slide out twice also, made a mess. For now I just have a wire hook to help it stay, couple of years probably by now. I can’t even pull it out when tight but somehow if wiggled its way. I had the puke hose and valve cover off, there's nothing to plug in the valve cover, no filter. Since I hardly ever see a drop on the floor under the hose, I don't worry about it.

[Rikadoo]

So customer didnt want to remove vc, so i made a hook out of a clothes hanger, next time he comes in we shal see how it did

[dl_racing427]

There really shouldn't be that much pressure inside the crankcase.
He should definitely investigate the cause instead of just tying down the dipstick.

[diplomat don]

Don't know if there should or shouldn't be that much pressure but Cummins always had a twist to tighten dipstick or turn and hook dipstick on their engines unlike Cats that just pushed in and didn't pop out. Last company I drove for had a late 90's Pete with 400 Cummins and had to keep the dipstick wired down to keep it from popping up and making a mess. Was always like that from the time I started with them until I retired 9 years ago and saw that truck 2 years ago and still going grossing 105,000 lbs. Doesn't seem to be doing much damage to the engine. 

[Rikadoo]

Its funney i dont believe that the dipstick popping out was a design feature to let the operator know there is a service due or safety measure for a couple reasons, now the cummins of today have a latch style an like yourself operators have been strappin them down since i worked on the 350 an 400 big cam cummins since i worked in the trucking industry MANY years ago. I just believe it was a design flaw that no one thought it was important enough to change it till just reciently, an whats even MORE FUNNEY is no enterprizing person thought enough to make a better aftermarket fix for it🤦‍♂️ JUST THINK ABOUT IT… If ole scooter had to clean his engine for the 2 or 3rd time you gotta know he woulda bought one, or even 2 so he could give one to his buddie…

[diplomat don]

Strange though Rik. I started out driving Cummins with the push and twist expanding dipstick and was always around them as lots of companies have multiple engine brands but the last company was the only engine I saw that issue and they had 2 identical trucks but only the one had that issue. Go figure. Don

[Timo in WI]

A quick Blow-by test on the Cummins B&C Series engine is:  loosen the oil fill cap (on the timing cover) with the engine running at idle.  If the cap "dances" on the fill tube, it's an indicator that there is excess pressure in the crankcase.  The cap won't "dance" on a better? engine.  I don't know if this indicator test is applicable on an ISL since the cap is on the valve cover, and at is larger/heavier.    An "unhealthy"/consistent amount of blow-by will cause oil leaks at the front and rear crankshaft seal.  Also, did the dipstick pop-out when the unit was heavily loaded, long uphill pull, high boost situation.   None of this solves the situation, but gives an indication of supporting symptoms.  

[timaz996]

I had this problem four years ago and replaced the expansion boot on the dipstick and it solved.

[96 EVO]

Don't know why, but I read on IRV forum, more hi crankcase pressure faults on 425HP ISL's than any other Cummins engines 🤔.