Couple of questions about my Merc Thermostat Housing

[dwna1a]

I’m working to fix an overheating issue on my FWC Merc 350. While doing this I’m replacing some of the much older system parts. Hoses, housings..the whole mess. So now I’m at the thermostat and it’s housing. My old housings were in rough shape.
The bolts on mine look like hell, threads are full of gunk. I’d like to just replace them, can I use Stainless steel ones? The old ones have a brass or copper sleeve, what is that for? Last can I drain and flush the cooling system, like you would a car? It a radiator flush kit?

 

[Scott215]

I seen people get away with soaking the thermostat housing and water and muriatic acid and they clean up nice perhaps some pictures would help

 

[dwna1a]

I seen people get away with soaking the thermostat housing and water and muriatic acid and they clean up nice perhaps some pictures would help

Scott, the old housings are from 1988, they are rusted and paint is flaking off. So I’m just replacing them and the hoses.

The heat exchangers will be next. MrCool has pretty good prices on those. Both of mine are leaking around the necks and one has some split tubes

 

[Scott215]

The new are very expensive for my 5.0 MPI I had seen that suggested here

 

[Pirate Lady]

Had to replace mine 2 years ago in the midst of an overheating problem. RWC 30yo, the hose barbs were half eaten away.
$400 for a new housing. That hurt.

 

[Fill Ess]

^^^ same here. I did both of my 5.0 MPI. They were around $400 each. Plus then you're into it for the sensors and senders as well, unless you can get the old ones out and they still work.

Hardin does make aftermarket ones in stainless, that look really nice and are cheaper, but only certain models. They didn't do one to match mine.

Old

New

 

[dwna1a]

Mine weren’t cheap but it’s one less issue for myself or the next owner. Hose kits were just as pricey

Im not throwing parts at an issue, most of my parts are original 1988 parts. If I’m replacing parts on one I might as well do two. I know I won’t get my money back from the work I’m doing but a new owner MIGHT be happy to see it done

 

[Scott215]

I know $450 for a thermostat housing is nuts

 

[ttmott]

I'd be cautions on using stainless steel fasteners unless you upped to 316 stainless. 18-8 stainless (ACE and Home Depot) will suffer from what is called Stress Cracking Corrosion when used with dissimilar metals and a water environment and will fail before any cast iron goes away. Secondly, anytime stainless is used to fasten aluminum there must be galvanic isolation or the aluminum will soon go away. TefGel is a good isolator.

 

[Pirate Lady]

Right Phil, sensors extra. That was an expensive summer. But hey, I’m good now for another 30 years.

 

[Scott215]

Arp fasteners

 

[JHornsby3]

When I had the issues with our older (1977) heat exchanger, I opted for a local shop. They replaced several of the core tubes and resoldered the whole things for $73. And they warrantied it for 2 years. Sure beat the price for a new one at $350+.

 

[Scott215]

I remember when candy bars were 25 cents not a $1.25 The good old days

 

[JHornsby3]

I remember when candy bars were 25 cents not a $1.25 The good old days

Or back about 1996 when the BK Whopper was $.99. I lived off of them. Got a $75 a day per diem and lived off of $5 a day. Ah, the good ol days.

The local shop, Mac's Radiator wanted $500 for the new exchanger. I was shocked at the $73 for the job.

 

[dwna1a]

My problem with the exchanger is the neck area. Both are very thin and both have small pin holes that leak.

 

[JHornsby3]

A good shop should be able to replace or repair the areas. At least that is what they told me. I asked about a bent neck on mine. They said they could replace a neck if it couldn't be put round again. It's best to not drop them. And if you do, don't let it land on your foot trying to stop it.