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Atomic 4 Help needed!!

DeFranco84

Member I
My struggle with my 1975 Atomic 4 engine continues. Ive now moved on to the cooling system. We idle at about 150 ish and the tempature starts to increase with load. at 2000 rpm it hits around 200 degrees and icreases with load. While trying to pinpoint the issue I went to test the thermostat and realized the previous owner must have taken it out and the engine has no thermostat. I ordered a new Thermostat and a new tempature sending Unit and matched stuart werner gauge from Moyer. In The meantime I acid Flushed the system , Bucket tested my flow rate, Flushed my heat exchanger and tested flow and refilled, replaced my impeller. Nothing helped. Where Else should I look? Any advice??
 

toddster

Curator of Broken Parts
Blogs Author
Often when people remove the thermostat, they put a bypass valve in the hose that leads to the thermostat housing. May need a tweak?

Freshwater or saltwater-cooled?

What was the result of your bucket test?

Have you looked at/changed the impeller? After an impeller dies, there are often bits of it stuffed into fittings downstream...

Sometimes, the rust is the only thing holding a cooling system together, and once you do an acid flush rotten parts make themselves evident... n expensive proposition. Don’t ask me how I know...:rolleyes:
 

steven

Sustaining Member
I had this problem a few years back. In addition to thermostat issue, I had a corroded and leaking water jacket.

As you face the engine from the front, on the left about mid way back is a 2inch-ish by 4in-ish plate that covers access to the water cooling jacket. If it is rusted out, water leaks out and you get insufficient flow through the engine with or without a thermostat. Replacement is cheap, easy and available from Moyer.
Here is a pic of the corroded one I replaced.

Mine is raw water cooled. I do not know if it is an issue on FWC.

water jacket side plate - Atomic4.JPG

--Steve
 
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