Deuce Coolant Filter Plumbing

[ceetwarrior]

Hey guys, I put a new coolant filter setup on my '67 M35A2 Deuce. Did I plumb it correct? I tapped into the thermostat housing after finding some free fittings at my neighbor's. But after the first drive the inlet hose wasn't warm but the outlet was hot as well as the filter. I'm wondering if I need to plumb into the other plugs to the left of the state housing in pic.

Thank you in advance.

 

[goodwithwood35]

Plumb the inlet to the other side of the thermostat, either from the block drain above the starter, or the plug under the temp sending unit on the water manifold. That way it always sucks from the supply. The way you have it, it is only pulling from the small amount of bypass from the thermostat or pulling when it is open. Which isn’t very often this time of the year.

You’ll be amazed how fast these filters fill up. You’ll want to have several on hand until things clean up a bit. You’ll know when the hoses are no longer hot as the radiator upper hose is.


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[ceetwarrior]

Ok, I ordered some other fittings. I flushed system best I could and I'm using Zerex nitrite free heavy duty coolant. Can't wait see that filter.

Thank you

 

[cbrTodd]

Ok, I ordered some other fittings. I flushed system best I could and I'm using Zerex nitrite free heavy duty coolant. Can't wait see that filter.

Thank you

If you're talking about the Zerex G05 coolant, I would be very hesitant to use it on anything as old as the deuce, which likely has some silicone in its gaskets. Despite the manufacturer's claims otherwise, my experience is that it still damages silicone gaskets. I flushed the coolant in my M923A2 and used G05 and the head gasket started leaking a year later when the coolant seals were eaten away. You won't get that with the regular green coolant.

A Word of Caution About Organic Acid Type Coolants

The subject of this post is my 1990 M923A2 with the Cummins 6CTA 8.3 engine. It was a 2009 "rebuild" at Kansas, including a tag on the front of the engine that says it has standard bore liners and standard size main / rod journals. When I bought the truck from GL in the fall of 2013, it had the...

steelsoldiers.com

It's your truck so do as you wish. I just thought I would warn you of what I went through, admittedly on a different truck.

 

[ceetwarrior]

Thanks for any advice you can give me. This is the most heavy duty truck I've owned before. I run Rotella red ELC on my 7.3L power strokes one with green 620 Loctite on new injector cups one with factory cups (that's a debate in the 7.3L world). This is the Zerex coolant I bought from NAPA for deuce, see pics:

 

[cbrTodd]

I had to look that one up on Napa's website. I didn't know Zerex made so many different types of coolant! The specifications for that coolant do call it out as being an OAT Organic Acid Type coolant. OAT are the ones that have tendencies to eat away silicone. I have no personal history with that coolant, but given my experience with two other OAT coolants (G05 and the orange Dex-cool) in older engines, I personally wouldn't use it. The potential cost savings of a slightly longer coolant change interval are much less than the cost and hassle of having to do a head gasket change. It's just not worth it for me.

It is your truck and your use case may be different than mine, so like I said you can do as you wish. For me, I run green coolant, use coolant filters like you have installed, and I check the coolant chemistry with test strips every year and add SCA as necessary.

 

[ceetwarrior]

I don't like the sound of acid coolant. So you just use normal green stuff, like super tech?

 

[cbrTodd]

I don't like the sound of acid coolant. So you just use normal green stuff, like super tech?

Yes just the plain green stuff. The Napa equivalent is "NAF 1GAL" if you want to stick with something from Napa. It looks like it is on sale here, not sure about your location.

The multifuel has dry liners so it doesn't technically need the SCA additive since the additive is to prevent cavitation on wet liners. It won't hurt anything if you put an appropriate amount in, though. I do since I already have it for my other truck. Too much supposedly can damage aluminum components so don't go overboard if you do use it.

One last parting thought - I am not completely against OAT coolants. I use the Zerex G05 in my 2005 Dodge. They are fine if the seals used are compatible with it, and most newer engines are. The red coolant you mentioned is likely an OAT coolant. It is just these older engines that were made with silicone seals where problems can happen.

Good luck!

 

[ceetwarrior]

I flushed out the OAT and put regular Fram in there. This time I pulled the block drain plug and did it right. So glad I did. For anyone wondering where it is located see pic 1. My flashlight is shining on it. It was a PITA to get out but the right tool combo and a 3/4 breaker bar. I re plumbed the coolant filter and flushed it out of OAT.

 

[goodwithwood35]

Here is my setup for my replacement engine

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[Gypsyman]

Kicking an old one up for a question. I have seen the basic flow diagram for the cooling system but I'm not really finding anything on the water pump ports. I'm piecing together a coolant filter system and I have the heater installed on my truck. rather than tapping into the thermostat housing is there any reason that I couldn't use the port on the side of the water pump? See attached photo...

 

[Gypsyman]

Disregard. PS Magazine to the rescue. Wish I could sit down and read every single copy of that old mag.