Rust alert. Coolant reservoir

Topic: Rust alert. Coolant reservoir (Read 1260 times) previous topic - next topic

Rust alert. Coolant reservoir

August 03, 2017, 05:02:27 pm

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 – August 03, 2017, 05:47:26 pm

Quote from: Bob & Sue – August 03, 2017, 05:02:27 pm

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 – August 03, 2017, 05:55:14 pm

I'll be checking mine too.

Re: Rust alert. Coolant reservoir

Reply #3 – August 03, 2017, 06:11:48 pm

Quote from: craneman – August 03, 2017, 05:55:14 pm

I'll be checking mine too.

Me three

Re: Rust alert. Coolant reservoir

Reply #4 – August 03, 2017, 06:18:38 pm

Four

Re: Rust alert. Coolant reservoir

Reply #5 – August 03, 2017, 06:41:46 pm

Uh oh need Ospho.

Re: Rust alert. Coolant reservoir

Reply #6 – August 03, 2017, 07:00:14 pm

Quick work! It would be nice to wait for a coolant change out, but I will have to have a look see...
Don

Quote from: craneman – August 03, 2017, 06:41:46 pm

Uh oh need Ospho.

Re: Rust alert. Coolant reservoir

Reply #7 – August 03, 2017, 07:02:29 pm

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 – August 03, 2017, 09:17:16 pm

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 – August 03, 2017, 09:53:06 pm

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 – August 03, 2017, 10:15:42 pm

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 – August 03, 2017, 10:25:47 pm

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 – August 03, 2017, 10:27:38 pm

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 – August 03, 2017, 11:49:06 pm

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 – August 03, 2017, 11:54:52 pm

Quote from: Bob & Sue – August 03, 2017, 11:49:06 pm

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 – August 04, 2017, 01:45:20 am

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 – August 04, 2017, 11:40:47 am

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 – August 04, 2017, 12:01:17 pm

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 #18 – August 04, 2017, 12:05:26 pm

The Ospho wins. I do brush it on
POR 15 Metal-Ready vs. Ospho | Shamrock Boat Owners' Club

Re: Rust alert. Coolant reservoir

Reply #19 – August 04, 2017, 12:15:50 pm

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.

Re: Rust alert. Coolant reservoir

Reply #20 – August 04, 2017, 01:47:39 pm

Meant to say the POR15 paint was better then rustoleum paint,ospho and the metal prep are both acid based.

Re: Rust alert. Coolant reservoir

Reply #21 – August 04, 2017, 02:53:48 pm

NCPTT | Comparative Study of Commercially Available Rust Converters

Your tax dollars are working to evaluate each of the above mentioned rust inhibitors. Phase 2 results will be available later in 2017. "The project's final goal will be to test the best two rust convertors with the addition to [sic] a painting system and test this until failure."

There is some worthwhile information in the link like primary ingredients & pH.
-Mike-

Re: Rust alert. Coolant reservoir

Reply #22 – August 05, 2017, 12:19:52 pm

Interesting, Bob's '95 has sight glass our '99 doesn't. Finished yesterday total coolant loss, less then 1/2 gallon. Siphoned out of tank to coolant bottles I hadn't thrown away when I changed coolant. About 5 1/2 gals.
Edit: his doesn't have the low coolant sensor probably why no sight glass.

Re: Rust alert. Coolant reservoir

Reply #23 – October 19, 2017, 07:24:25 pm

Reviving this old thread because I found something interesting on our coach. I finally got around to looking at our tank, and discovered there is a sheet of some kind of plastic between the metal tank and the metal bulkhead to which it is bolted. I didn't get around to unbolting the tank today, but I snapped a couple pics trying to show the plastic sheet. Has anyone else run into this stuff? I'm hoping the plastic may have prevented the heavy rust found on other coaches, since it prevents metal-to-metal contact between the tank and the bulkhead. Once I get the tank pulled loose, I will report back.

Don't know if the photos really show the plastic... It is "sandwiched" between the tank and the bulkhead, and held in place by the tank mounting bolts.

Re: Rust alert. Coolant reservoir

Reply #24 – October 19, 2017, 08:10:19 pm

Don't know why FOT would install that plastic sheet on a 93 and not on a 95?
I just removed and repainted ours last weekend and no such separator was installed. Couldn't have been "cost reduction" on a 250K plus coach!
Sounds like a good idea, but maybe it didn't work?
Let us know what you find.

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