coolant leak on 350 cummins

[danwes]

2002 winnabego 40e UA 350 isc cummins, 52,ooo.

I have coolant leak somewhere on top of the rad., but not in the core as i can tell at this time. It only leaks when the holding tank is full with the engine turned off. You can run with tank low and it will not leak. My thought is the small 1/4" hoses located on top of the rad. is leaking. I can see the one on the rear, but can not the one on the front. [side rad.]. Anyone have any ideas on this?? Thanks for your input Dan Thomas

[AFChap]

It does sound like something to do with the connections to the holding tank, or perhaps the tank itself. Some folks have found cracked plastic overflow holding tanks. That would match your symptoms too. I don't recall for sure if your 02 has a Spartan or Freightliner chassis, but seems I have heard the cracked holding tank problem most often happening on a Freightliner.

[danwes]

Thanks for the reply, Paul

My holding tank is metal, it's a spartan with a side rad. The leak is the best i can tell is somewhere on top of the rad. and i am thanking possible it is a 1/4 hose going to the top of the right side of the rad. Can't see back in there. I may have to unstack all the other coolers to get to the top. It does not appear to be leaking in the core. Thanks Dan

[targaboat]

We are not there and can not see for our selves. Sometimes a mirror helps. Of course right after start up is the best time to look.