Thermostat for an M

A number of years ago someone gave me a NAPA number (I've misplaced) for an automobile thermostat that would work in an H (and it did)but much less expensive than the IH version. Now I'm getting ready to assemble a rebuilt M engine and wondered if anyone out there had a similar number handy for an M.

Thanks in advance

H and M use the same thermostat.

H and M use the same t'stat.

For my SH and SM I took the thermostat housing to Autozone and tried different t'stats until I found one that fit the housing. (Autozone #800-180 maybe? - it was a while ago...)

The AZ t'stat looks different - it's much shorter than the OEM t'stat. But they work great in both my tractors.

This subject has been discussed several times on these forums. If you will trace the water flow through the thermstat housing , to water pump, to radiator etc you will see that by installing a automotive type (less costly) thermostat it will indeed "work". Problem is that it blocks all flow through the bypass system there fore no circulation will take place in engine until thermostat opens. This is not good as hot spots will develop internally. IH made an error back in the late 70's or early 80's, substituting incorrect thermostat, quickly discovered their mistake and had a recall of those thermostats and advised any that were installed to be replaced with proper ones. Often times the type supplied by CaseIH will not give desired results. This is not fault of the thermostat, rather the fit of it in the upper housing allowing coolant to just flow right on by to radiator. These housing rust out badly over the years. I have had a machine shop install a seal in some housings but on others there is not enough material to allow this. For them I put a loose fitting O-ring on thermostat along with a thin flat washer and a light spring below it to hold o-ring up against upper housing cutting off this flow and it has been working out quite well.
The housing on my own M was so bad I had to locate a different one to make it seal the way I wanted it to.

Use the original style for best results; NAPA or your IH dealer can assist you.