CM871 Lots of oil in coolant

[TheBud]

Have a Kenworth with a CM871, had oil seeping into coolant, small amount of oil, replaced Oil Coolers a month ago, problem solved, zero oil in coolant.

Yesterday truck pulled into the yard literally pumping coolant and oil out of the overflow tube on the coolant reservoir, pushed 3 gallons of oil through the coolant system. There is novisible coolant in the oil. Removed oil the new oil coolers, no visible issues, having them tested. I suspect they will come back ok. What else would cause it to push that amount of oil into the coolant in a short amount of time?

[Rawze]

most likely cause ...

The wrong oil cooler element seal was used when it was replaced the first time?.

They have had oil cooler element changes over the years and seals to match them. It is a fairly common occurrence for it to fail again if the wrong seals were used.

Of course, it could be something else too. It could be the tranny heat ex-changer failing if it has one of those that uses coolant.


also, if this truck is de-mandated ... and it has one of those horrible delete programs in it where the oil temps gets above 235-F easily .. then that could be a heavy contributor too.

[TheBud]

You hit the nail on the head. Old cores were aluminum, new cores stainless.

Dealer supplied diamond shaped metal/rubber gasket type seals instead of o-rings required for the stainless cores. My eager young shop hand had the cores bolted up, as they were with the oval gaskets as it was with the aluminum cores before I could put my coveralls on. How it lasted a month, I'll never know.

[Chamberpains]

Ahhh yes, the cost of being a young go getter. Hopefully he got a good ear chewing that'll stick with him for life. Sounds like you might have a good hire on your hands. The biggest problem now-a-days is finding anyone that will even get their hands dirty and one that is willing to learn. Most people I run across are complete narcissistic infallible know it all's.

The internet "taught" them everything about everything but the real world has yet to prove how stupid they are.

My apologies for getting off topic.