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Jas2153 · 02-16-2025, **(Subject: N14 diesel in coolant )**

I took my radiator cap off and there was diesel in the coolant. I was told by a few people that a bad injector cup is the most likely problem. I know there are probably a number of other issues that could cause this problem. Can Cummins Insite help with diagnosing this before taking the head/motor apart? Motor is an N14.

tree98 · 02-16-2025, **(Subject: N14 diesel in coolant )**

No insite can't help you with this. You could pull all the injectors and pressurize the cooling system to 5 psi (no more than 5 psi with injectors removed) and you'll find the leaking cup/cups like that.

Jas2153

(02-16-2025 )tree98 Wrote: No insite can't help you with this. You could pull all the injectors and pressurize the cooling system to 5 psi (no more than 5 psi with injectors removed) and you'll find the leaking cup/cups like that.

Thanks. Any recommendations on flushing the radiator/cooling system?

Rawze

(Yesterday )Jas2153 Wrote:
(02-16-2025 )tree98 Wrote: No insite can't help you with this. You could pull all the injectors and pressurize the cooling system to 5 psi (no more than 5 psi with injectors removed) and you'll find the leaking cup/cups like that.

Thanks. Any recommendations on flushing the radiator/cooling system?

cummins restore, and following their instructions is the best way. Stay away from any kind of soaps in the coolant system.. its a nightmare to get it all out again.

hhow55

Bad injector cups?

Jas2153

(Yesterday )hhow55 Wrote: Bad injector cups?

Yes. Found out today.