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Topic: Rust alert. Coolant reservoir  (Read 1488 times) previous topic - next topic

Rust alert. Coolant reservoir

Our coach has a lot of miles on it but doesn't realy have much rust on it. All of the frame components are pretty clean, maybe a little surface rust if any        That you can see anyway.        But now I am suspect of any area that I CAN'T see.

  While doing a coolant flush / thermostat replacement / hose replacement procedure, I decided to pull the coolant reservoir off to clean it thoroughly.  And a repaint while it was off.  I was surprised to find a large amount rust behind it. There was no clues that this was going on. No rust trails below it and it wasn't leaking    yet. 

  So I pressure washed the reservoir (inside and out) and the panel behind it, along with wire brushing and a new coat of paint.  When I remounted it back onto the wall I used 3 fender washers behind each of the 4 mounting bolts to create a gap between the wall and the tank. Any moisture will hopefully drain away now.

  I see this as important because , if the tank and the metal panel ( common to the bedroom cabinet ) had rusted through at the same time there could have been moisture intrusion into the floor and beyond.        Because up to now I only checked the overflow bottle and never realy checked the tank.  If low on water I would have just added more coolant to the bottle.

  Coach will be in Nac this winter to check bulkheads.



Re: Rust alert. Coolant reservoir

Reply #1 –
Quote from: Bob & Sue –
Our coach has a lot of miles on it but doesn't realy have much rust on it. All of the frame components are pretty clean, maybe a little surface rust if any        That you can see anyway.        But now I am suspect of any area that I CAN'T see.

  While doing a coolant flush / thermostat replacement / hose replacement procedure, I decided to pull the coolant reservoir off to clean it thoroughly.  And a repaint while it was off.  I was surprised to find a large amount rust behind it. There was no clues that this was going on. No rust trails below it and it wasn't leaking    yet. 

  So I pressure washed the reservoir (inside and out) and the panel behind it, along with wire brushing and a new coat of paint.  When I remounted it back onto the wall I used 3 fender washers behind each of the 4 mounting bolts to create a gap between the wall and the tank. Any moisture will hopefully drain away now.

  I see this as important because , if the tank and the metal panel ( common to the bedroom cabinet ) had rusted through at the same time there could have been moisture intrusion into the floor and beyond.        Because up to now I only checked the overflow bottle and never realy checked the tank.  If low on water I would have just added more coolant to the bottle.

  Coach will be in Nac this winter to check bulkheads.

Bob,

Great preventive maintenance.....  Thanks for the heads up.....I never thought to look there!

Jerry

Re: Rust alert. Coolant reservoir

Reply #2 –
I'll be checking mine too.

Re: Rust alert. Coolant reservoir

Reply #4 –
Four

Re: Rust alert. Coolant reservoir

Reply #5 –
Uh oh need Ospho.

Re: Rust alert. Coolant reservoir

Reply #7 –
Maybe just soak some Ospho down behind it but I know I too will be removing it now seeing the pics.
JohnH

Re: Rust alert. Coolant reservoir

Reply #8 –
Kinda strange place for so much rust.  Fairly high up off the road, not near the rear wheels, in a hot engine compartment.  Wonder if there is some kind of repeating condensation thing going on there, due to differing temps of the liquid in the tank and the metal behind the tank.

Now I'll have to check ours...

Re: Rust alert. Coolant reservoir

Reply #9 –
It looks like metal is corroded on both surfaces, the panel and the tank. Looked behind the coolant overflow and nothing serious going on there. Ready for paint tomorrow after Ospho dries.

Re: Rust alert. Coolant reservoir

Reply #10 –
What is Ospho?  Is it a rust reformer?  Is it better than the Rustoleum rust reformer or the same?
John M.



Re: Rust alert. Coolant reservoir

Reply #11 –
I am not familiar with Rustoleum rust reformer. This product is used on the fire dept. ships and I found out about it by a fireman.

Re: Rust alert. Coolant reservoir

Reply #12 –
I believe this rust issue is caused by the coolant tank getting hot and creating condensation. I will space the tank with washers Like Bob did.

Re: Rust alert. Coolant reservoir

Reply #13 –
 Craneman.
  I forgot about the Ospho thing. It acid etches, right.    I did wire brush all the surfaces completely and wipe it down with alcohol before I primed it.  Hopefully the paint sticks good. 

Bob

Re: Rust alert. Coolant reservoir

Reply #14 –
Quote from: Bob & Sue –
Craneman.
  I forgot about the Ospho thing. It acid etches, right.    I did wire brush all the surfaces completely and wipe it down with alcohol before I primed it.  Hopefully the paint sticks good. 

Bob
I don't think it acid etches, it changes iron oxide (rust) into another chemical which looks like black primer and locks it to the metal.

Re: Rust alert. Coolant reservoir

Reply #15 –
Ospho is phosphoric acid, primarily.  Rust Reformer and other similar products are tannic acid based with a polymer additive.  They make a hard, shiny prime coat over converted rust as opposed to just rust neutralization effect of Ospho. 

Rust reformer (in the brush on form, the spray on stuff is worthless) is the weak sister of this product family.  The absolute best I've found, tried and true on the hyper saline gulf coast of Tx. is branded Conquest.  Hard to  find and buy unfortunately, but I've brushed a coat on rusty steel and left it out in the salt air and dew for six months with no further rusting. 

Re: Rust alert. Coolant reservoir

Reply #16 –
Waiting for the Rustoleum black appliance epoxy to dry. The electrolysis of the tank is stopped but if left unnoticed could eventually cause a leak. It doesn't look like the sheet metal on the coach has the bedroom right on the other side, more like a double panel of some kind.
Thanks Bob for finding this one. I will finish the project after work today.

Re: Rust alert. Coolant reservoir

Reply #17 –
My opinion would be to go one step better and get some POR15 and brush on,much better then rustoleum.Could be the tank was never painted to begin with.

Re: Rust alert. Coolant reservoir

Reply #19 –
When I worked on tuna boats and tug boats we used a product called Corroseal, a rust converter. Looked like milk when you painted it on, then when it was cured was a black color. Very good stuff.