Replacing Surge Tank

mobill · 02-27-2010, 08:29 AM

Like several other people, we starting having trouble with leaks from the coolant/surge tank in our motorhome. We decided to replace the tank, but were given the tank designed for trucks when we went to Freightliner. When we called them back about it, they said the tank for motorhomes would be about $700. That seemed excessive, so I started searching the forums for more information. I see that several people have installed the surge tank designed for trucks in their motorhomes after some modifications to the bracket that holds it in place. (A special thanks to the guy who included pictures of his work.) I believe that is what we are going to do, but I have a question. Is there any problem getting the antifreeze into the top hole in the tank once it is in place? The old tank has a cap and opening on the side for filling. My husband is going to test it out before we do anything, but I wanted to see if anybody who has made this modification can tell me if it causes problems filling the tank.

Thanks!

2003 Tiffin Allegro Bus
Freightline chassis

doc · 02-27-2010, 08:45 AM

Why don't you call Gaffeny SC factory and get the part number for that year chassis and then search from there?

EngineerMike · 02-27-2010, 09:59 AM

My surge tank's hole is all the way at the top of the access lid, so there is no room to pour coolant from a jug. You can buy a small pump that fits the lid of coolant and/or lubricant jugs at NAPA, etc. that will do the job easily.

After you put in the surge tank, add a coolant recover/overflow tank. I used a heavy duty plastic jug, and cut a hole in the lid to snug-fit the overflow hose, and trimmed the overflow hose to nestle on the tank overflow tank bottom. Then I filled the surge tank well above the sight glass. No more lost coolant since I did that, so the number of times I have to play around w/coolant and the pump dropped to, well, no more messing w/it at all. If I did need to add some coolant, I could add it in the overflow (except during a coolant change) then drive around; after the engine cools down it will suck in whatever it needs till the surge is full.

Chuck 1935 · 02-27-2010, 11:12 AM

I changed my own surge tank and replaced it with the same style tank that was in there. I then added a flap to protect new new tank from UV rays. The pictures and advice made the job very simple. $107. for the tank and a few hours work and it was done. The hardest part is gaining access to the engine cover at the rear under the bed. I just slid the mattress off the side of the bed and stood it on it's side against the wall, removed the mattress deck and laid it up against the mattress and unscrewd the three bolt holding the engine cover down. Why bother with fitting a different style tank when it was the UV rays that killed the tank.

mobill · 02-27-2010, 12:57 PM

One reason we were thinking of replacing the current tank with the one made for trucks is that the current tank has 3 holes with caps. One is a pressure cap, one is for adding liquid, and the third has a cap with a metal piece that sticks down into the tank -- don't ask me what it's for. This third cap has never seated properly. The previous owner used putty or something to hold it in place, which finally gave out. Having just one cap seemed like less of a headache. Does anybody know the purpose of the cap with the metal piece that extends into the tank?