I have an early 04 common rail with a few mods and 80k on it. About a month ago it started to turn cold where we live and one morning I started my truck to warm up and came out to coolant gushing from the passenger front top of the motor. Replaced the water pump and still leaked so I started with the obvious and checked all the hoses and tightened the clamps. That cured it for about the past month now a different leak is back. Not as bad and the best I can tell it is around the lower part of the passenger front because it is dripping from around the ac compressor bracket and nothing I can see up top is leaking. It never had any issues until it started to get colder. Any ideas of what it could be? Is it just a cold water leak and nothing to be really concerned about? Also since the weather has gotten cold fuel is leaking (slight drip) from the drivers side front of the motor my guess is the cp3 pump it is running down the wire to the sensor at the harmonic balancer and sometimes drips frequently and other times just stays moist again I never had any leak issues when the weather was warm. I read somewhere these pumps are notorious for cold weather leaks. Is this something I should repair or replace or just something I should get used to.

 

Leaks are never something to be taken lightly.

 

That's what I was thinking I just bought my diesel in June of this year and love the truck it just seemed that it wasn't until it started to get colder that it started springing leaks. The antifreeze leak is a real pain because its so intermittent. I was hoping someone might know of a common leak problem in that area. I am also concerned about the fuel leak common sense says to pull it apart or take it to a shop to confirm that is what it is, but if it is the cp3 leaking I have just heard so many mixed opinions about these leaking on common rails. Some say its expected and its because of the metals others like myself are concerned about $ running onto the ground as well as hp.

 

You can get away with ignoring small leaks as long as you keep fluids topped up. But the problem always becomes what is "small" to you, and small leaks usually eventually become larger leaks. The consequences can be costly if that happens suddenly or in the wrong place at the wrong time.

 

So it turns out after chasing my tail for nearly 2 weeks that all along it was the new water pump leaking. I really cant be sure rather the pump was bad or just the seal on the pump. I literally ran out of options and opted to replace the pump as my last option and it turns out since doing so I have had no more leaks. Since the leak last time I know there is some debate over using silicone on the pumps when installing them. I am glad I did be cause that seal provided is not a very promising design in my eyes and you know what, no leaks now that I did I am not pointing fingers but I have a suspicion that the seal leaked that's why I seen this more in the cold weather. Even though it is going to be a little more work to clean up next pump replacement well worth not having to mess with it in freezing temps.

 

Ahhh, the water pump saga plays itself out once again. Pretty common scenario unless you are buying the right parts.

My guess is you bought something other than a NEW water pump from Cummins. Your expereince is typical for that scenario. Not all catings are as exact or componeents that high of quality on the common sources so issues abound. The o-ring seal is no problem IF the o-ring is of good quality, the casting is machined to the correct size, and the mounting surface is adequately cleaned. One piece of scale wll cause an intermittent leak. On small piece of missed silcone sealer will case the same thing. If you don't buy the new Cummins unit, YMMV.

The CP-3 leaks are common, especially in cold weather. You have an aluminum and cast sandwiched together. Expansions rates vary so they leak. Even the update dpumps can seep a bit in cold weather. As long as it is not a stream that leaves a puddle or coats the under part of the truck, a periodic spray down with a cleaner and water keeps it clean. There is a set of over sized o-rings that may help if one is inclined to put them in.

 

Yeah it was new pump from NAPA I didn't read or hear about how important it was to replace the pump with original Cummins equipment. So lesson learned but in the meantime the additional silicone I repaired it with this time should out last the pump. As far as the CP-3 thanks for the info on the over sized o rings I may look into those. It never leaks a stream just a few drops from sitting or during warm up never from driving a s far as I can tell and no fuel has ever sprayed back on the under body of the truck. A job for warmer weather if it continues if not I may just except the fact my Cummins doesn't like the cold weather either and just add a block heater.

 

It doesn't leak in warmer weather so there is no reason to work on it. LOL! When it is cold it is too hard to work on it. Even the the CP-3 I had replace dunder warranty leaks in cold weather so in the 6 years I have had it, clean it up occasionally and its all good.