Coolant leaks when it's really cold

[AKDoug]

Do any of you have issues with coolant leaks on a truck that sits at 0F and below. Both my CM570 and CM870 leak from the water pump o-ring when it gets really cold. We've replaced o-rings several times to no real success. Lubed with lubriplate grease always and always using OEM Cummins o-rings.

Does anyone have a magic cure other than park the trucks inside?

[tree98]

my 870 would leak when really cold outside too. Didn't leak much so I never did anything about it did. Just enough to make a small puddle.

[Coronado126]

The water pump housing isn't starting to get grooves or any signs of wear right?

While I've never had this happen, Cummins does say that use of petroleum based lubricants will cause the oring to swell and leak. All the products lubriplate makes are petroleum based that I've ever used.

You might try it again a silicon based non petroleum grease. I like Sil glyde. It's made by AGS but Napa rebrands it and sells it under their name as well, but anything non petroleum lubricant would work.

[marek4792]

check your coolant/water ratio, could be too much water causing o-ring to fail due to expansion.

[hhow55]

Might want to check and see if their has been an update to a different oring
This happened to me before

[Rawze]

I always coat the o-ring in thin layer of anti-sieze when installing. Have not had one leak.

[Signature620]

The 570s always leak from the plastic cover on the back side. There's a repair kit for them but worth replacing the whole pump if it's a few years old.

[JimT]

(12-15-2020 )Rawze Wrote:  I always coat the o-ring in thin layer of anti-sieze when installing. Have not had one leak.

I'll second the anti-seize. Used that exclusively on all the o-rings and gaskets during my engine rebuild (except injectors) and have had zero leaks from any of those locations.

[AKDoug]

Thanks for the advice. We'll try that anti-sieze idea. Can't hurt. Will look at that plastic cover as well.