X15 Random Coolant Loss

[BobbyTTour]

We have a 2019 X15 with 330,000 miles that is randomly consuming coolant. It consumes 1-2 gallons after the driver stops for his 30 min break after driving for a few hours. He will check it when he stops and it may be down about .25-.5 galleons, and within driving 20 miles after the break, he gets the low coolant warning and has to add 1-2 gallons. It will then be fine the rest of the day and might be down .25-.5 gallons at the end of the day. This has happened for two days in a row. He stopped at a shop and they performed a pressure test and said they couldn’t find it and suggested we replace the injector cups. I was thinking it was and EGR cooler issue. Thoughts?

Thank you.

Robert

[BobbyTTour]

The driver sent me a video of the overflow tank bubbling after shutting the engine off. I’m uncertain how to post it though.

[Rawze]

Your description so far is exactly the symptoms of a partially blown head gasket due to a dancing liner... not so much the egr cooler.

If the engine was de-mandated improperly (90%+ chances for improperly) then that is a heavy contributor of blown head gasket.

(Things that will effect engine life related to liner failure) ...
Is this truck de-mandated (deleted).. and if so, who did the work/programming?.
What make.model truck?.
How many miles (or miles since last inframe)?.
How much HP/Torque?.
What is the trucks rear end ratio?.

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You should also pressurize the coolant system to 20-psi and fix any leaks first too.

next step would be pressurizing the coolant system to 20-psi and letting it sit over night with the oil pan off the engine. Then the next day, look for droplets of coolant seeping out from around the piston rings on each cylinder at each compression stroke, as someone turns the engine by hand. You will either hear a dry hiss (good) ... or a gurgling sound(bad) + dropplets on the cylinder that is blown.

[BobbyTTour]

The truck is still 100% compliant. The shop pressure tested the system and did find two very minor leaks which were resolved, but didn’t pull the pan. Oil is not cloudy nor is the level rising.

2019 Peterbilt 579
330 original miles
525/1850
18spd
3.25 rears
LP22.5

[Rawze]

(05-14-2023 )BobbyTTour Wrote:  The truck is still 100% compliant. The shop pressure tested the system and did find two very minor leaks which were resolved, but didn’t pull the pan. Oil is not cloudy nor is the level rising.

2019 Peterbilt 579
330 original miles
525/1850
18spd
3.25 rears
LP22.5

First of all ... The statement "oil is not cloudy or rising" means absolutely nothing at all and is no indication of anything. A failing head gasket typically does not do this to the oil... though it might show some small signs of coolant intrusion on an oil sample from a lab... and sometimes not even then.


Next.. is that fact that it is 525hp,1850trq combined with horrible 3.25 rears in it. - That is absolutely a terrible setup that will definitely cause that engine to suffer a shortened lifespan, eventually blowing a head gasket (dropped liner) due to it lugging its whole damn life below 1500rpm.

- That spec is set up for pure engine torture like that, I would not give that engine more than about 500k miles before an inframe as it is, set up like that, ... so it certainly would not surprise me if it blew out at 330k miles, especially if someone is driving it hard (foot to the floor all the time + too lazy to down shift on hills half the time).

You could not give me that truck ... it has taller rears than my S.U.V. ... ready to lug the engine its whole life into an agonizing death. I would have had to change out the rears to something made for hauling freight, the day it was purchased.


If it is not simply some weak hoses/coolant leaks .. which you say, were fixed.. then the next step is to drop the pan and do what I said above, to find it.