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AirBossdavid · 07-07-2020, 04:10 PM

I have a 2001 holiday rambler, ambassador, 34 pbd w/isb260 Cummins.
The radiator expansion tank is plastic (I think) and has cracked in a Couple of places Which leak.

I have tried patching it with Epoxy, jb weld, and metal reinforced bonds with some fiberglass Matt. I have even let it sit for days to cure. I have cleaned, sanded and washed with acetone before patching.

Each patch looks great and seems to adhere but at some point a day or so after it starts to leak again and the patch comes off in one piece.

Anyone know of a good way to repair the tank or find a replacement?

Bigd9 · 07-07-2020, 04:17 PM

If your tank is like mine, it is under constant pressure as the coolant flows into and out of it.

If your coach has a Freightliner Chassis, you should be able to take your VIN number to them, and they can tell you everything about your chassis. If luck holds, they may still have the one your coach uses in stock someplace!

BTW, those tanks are a constant source of complaints about cracking and leaking on this forum. You are not alone.

FleetMan · 07-07-2020, 04:18 PM

There are many posts on this common issue with the Cummins radiator tank. Some include pictures, procedures used, short cuts, replacement part information. Search the archives.

AirBossdavid · 07-07-2020, 05:23 PM

Maybe I don’t know how to search. I’m pretty new here. I tried expansion tank, radiator tank and now Cummins radiator tank as you suggest and found nothing in this topic. There are some posts about overflow tanks but I don’t see anything about expansion tanks. Can someone help me understand how to do this search?

AirBossdavid · 07-07-2020, 05:24 PM

Thanks. Unfortunately it’s a roadmaster chassis. Freightliner has no info.

vito.a · 07-07-2020, 05:55 PM

Monaco did not make the plastic tank. Most were Volvo tanks but they used others as well. You need to replace the OEM plastic tank with a steel tank.
Try this one:
Radiator Overflow Tank, Metal **ONE WEEK LEAD TIME**: nwrvsupply.com

Source Engineering is another place:
http://sourcerv.com/products

You might also look at the tank Dodge uses with the ISB engine.

Some folks have built there own expansion tank or had one built.

tropical36 · 07-07-2020, 05:59 PM

Quote:

Originally Posted by AirBossdavid

Maybe I don’t know how to search. I’m pretty new here. I tried expansion tank, radiator tank and now Cummins radiator tank as you suggest and found nothing in this topic. There are some posts about overflow tanks but I don’t see anything about expansion tanks. Can someone help me understand how to do this search?

Being plastic, I assume it's just an overflow tank and you might try here...
https://www.google.com/search?q=moto...hrome&ie=UTF-8
Mine doesn't have one and in it's place, a steel expansion tank with a pressure cap and the old standard overflow tube, going towards the ground and for which I've hung a plastic bottle on. This is only so I can see if the cap is weak and lifting for losing fluid.

HarryStone · 07-07-2020, 09:21 PM

The plastic you have is probably slick to the touch, which makes is hard to get something to stick. I've had success in the past with a plastic specific epoxy. JBWeld and Loctite make some good stuff. I've even epoxied the inside of a door panel, that was made with a very slick plastic. While it wasn't under pressure, it worked pretty good.