[66 Wagon]

I found a coolant leak the other day. It was behind the timing chain cover so I removed the cover to replace the gasket, that had got a 1/4 of an inch "crack" in it.
To my surprise when I removed the waterpump from the cover it had corroded quite much inside. (see pictures)



The engine has run 12,000 miles since the rebuild three years ago.
Both the cover and pump were as good as new with no sign of corrosion when it was rebuilt.
The engine has always had antifreeze, I might add, and has never overheated.
As you can see the corrosion is where the waterpump divider is located.




Is there any possibility that the stainless steel water pump divider reacts with the
aluminum timing chain cover and the cast iron waterpump and causes the corrosion?

[Pepi]

Wow!! I would think dissimilar metal corrosion could have happened there with the stainless steel divider plate.

[Blued and Painted]

Was it Dex/Cool?

[66 Wagon]

Originally Posted by Blued and Painted

Was it Dex/Cool?

I'm in Sweden and Dex/Cool is something that's not available over here.
I have used plain ordinary "blue" ethylene glycol of a major brand sold at gas stations here
and have had the 50/50 mix with water.

[RamAirIV28]

do you also have electrical or charging issues? is the engine, frame and body properly grounded?

[66 Wagon]

Originally Posted by RamAirIV28

do you also have electrical or charging issues? is the engine, frame and body properly grounded?

No problem with anything electrical.
All the ground straps are there.

[sts]

Raiv mentions something called galvanic corrosion, the same thing that I suspect.

Coolant has an electrolyte value of whatever x-percent. High resistant ground causes stray current to follow the path of least resistance, and the coolant acts as an electrolyte in which the stray current travels.

It isn’t a case of having electrical problems that you notice such as not starting, or fire jumping around under the hood. The problem is the small amount of stray current will eventually eat up an assortment of metal parts, and the problem comes from high-resistance ground connections or lack thereof. His point was that low-resistant ground connections eliminate this problem, of course, if that’s what’s causing the problem. By the way, ground straps in the proper locations doesn’t mean that they aren’t suffering from high resistance connections.

[sts]

Also, do you use distilled water because salts in normal water sources can also eat cooling systems alive.

[66 Wagon]

I'm not using distilled water. I use the same water I drink, right from the kitchen faucet.
Can the stainless steel in the divider plates dramatically increase the galvanic/electrolytic corrosion?
(which I think is the cause of the problem)

[Old Goat 67]

Originally Posted by 66 Wagon

Can the stainless steel in the divider plates dramatically increase the galvanic/electrolytic corrosion?
(which I think is the cause of the problem)

I would believe that to be the problem. I have wondered about that before and now I am thinking "if one uses a stainless plate, it would be advisable to put in some sort of sacrificial anode like we used to with stainless props etc. on boats." It's purpose was to minimize the corrosion of the aluminum engine parts.
We need to research that option.

Charles

[mchell]

The inside of your pump looks to have little corrosion at all, as well as yor timing cover.... ...looks like you had an old leak in the most corroded area..gasket failure gone unnoticed ?..that would eventually cause pitting

[66 Wagon]

Originally Posted by mchell

...looks like you had an old leak in the most corroded area..gasket failure gone unnoticed ?..that would eventually cause pitting

Not more dan a day between the timing chain cover gasket failure to the leak was noticed.
I have the hood open everyday because I disconnect the battery every evening and immidiatly removed the cover and pump after the leak was found.

[mchell]

Originally Posted by 66 Wagon

Not more dan a day between the timing chain cover gasket failure to the leak was noticed.
I have the hood open everyday because I disconnect the battery every evening and immidiatly removed the cover and pump after the leak was found.

Leak was found at the area corroded ?


Small coolant leaks (especially weeping) can go unnoticed for long periods as the coolant tends to evaporate quickly on a hot engine .......I wouldn't worry...the insides look good...the sealing surfaces on your ting cover look good ....get a new pump and gasket set....you should be good to go...or re- gasket what you got, provided the pump seal wasn't leaking... RTV should fill the minor pitting

[66 Wagon]

Originally Posted by mchell

Leak was found at the area corroded ?


Small coolant leaks (especially weeping) can go unnoticed for long periods as the coolant tends to evaporate quickly on a hot engine .......I wouldn't worry...the insides look good...the sealing surfaces on your ting cover look good ....get a new pump and gasket set....you should be good to go...or re- gasket what you got, provided the pump seal wasn't leaking... RTV should fill the minor pitting

I'm not worried. I've already replaced the gaskets for the cover and pump, rinsed the engine and filled it up with new glycol and destilled water 50/50.
No leaks, so far, after three days and 200 miles.
I will get a new timing cover and a new pump, with ILTs divider plates to be sure, and replace it all after the driving season is over.