hi ttman4,
I have been using the Stant #S-368 thermostat (International V-8 prior to 1970)
It has a 2.5 in. dia. flange and will require adaption to work on the D6, fits better with the single unit housing on the D4. The Cat retainer ring is 3.00 in. o.d. and 2-7/16 in. i.d. and will require a combination of washer and gasket to install. Not a real challenge considering the cost difference:D

There is another model #S-354 @ 2.875 in. o.d. but is 1.88 in tall from mounting flange which I've been meaning to check out but haven't yet. (65 - 91 Toyota Land Cruiser)

CCJersey has late model D6 which does not use the retaining ring mounting, same as late D4.

Thanks OM!
I'll ck 'em out in next few days & get my game plan lined out in my head. I don't have a problem with my tinkering, tweaking round & experimenting with things, just to see what I can & can't do, what will or won't work. That's how I understand it all better.
Back when I first started taking the T/housing apart & looking at things, I thought they were designed & put together totally different than they turned out to be.
But when I get serious & start using this machine, or let someone else on it, thats when things get sloppy & gauges not watched or something. Then I'd feel better having them all working correctly. Not be wondering "is my grinding & redesign gonna keep working...."

hummm, ironically, last March my son & I hauled off an engine from his '84-'86 Landcruiser that probably had a thermostat that I could have looked at....Oh Well!

That's why I never throw anything away:D
Also do my share of tinkering. How about a sheet metal plate the shape of the T/housing flange and hang the thermostats from that. Can't remember if the upper housing has flange face or open cavity.......now I'm gona hafta take one apart to look:rolleyes:

the face of the cover is flat on ours. the retainer-less housing appears to have a shallow recess in it to receive the thermostat flange. As I said, I couldn't see how to remove them without drilling a hole or chiseling them out of the recess. If you used a sheet metal plate, you could countersink them or just let the top cover do it if it was thin enough and soft copper or brass etc.

NAPA had one a couple years ago for the D311 that fit right in, sitting on top of the housing without the retainers. the thickness of the gasket left room for the flange of the thermostat. Would that do for the '6? Seems like it was close to $30 though.

I also see in my semi-old Stant catalog that they had both a Reverse poppet #347 series and a Balanced sleeve version # 370 series (195 deg max on both)
for the early D6's. Might be worth checking out if still available.

"Old wrote:

That's why I never throw anything away:D
Also do my share of tinkering. How about a sheet metal plate the shape of the T/housing flange and hang the thermostats from that. Can't remember if the upper housing has flange face or open cavity.......now I'm gona hafta take one apart to look:rolleyes:

Yeah, it's "treasure!" But All my neighbors & friends & the wifey always bitc*ing & poking fun at me 'cause this place looks like a bunch of inbredslive here, or it looks like Sanford 'n Sonlive here.....but guess who all comes running to see if "ya probably got one of these out there somewhere, I've looked hi 'n lo everywhere" or "you know everything, 'ya know how to fix this?"

Wasn't that long ago I had mine apart, & probably will have it apart again today or tomorrow. Not sure what you mean by flange face, but as I recall my upper was open with quiet a bit of upper room. And the contact face against the gasket was more or less even with, or a bit outside the lower hole where theromasts & retainer sit.
However, now thinking on it, upper may have covered the retainers slightly...??

Now I gotta go look!!! Hood's still off & I got to put antifreeze back in anyway....

BTW, hope everyone popped a "cracker" for me yesterday....Me & the boy that's in from Montana went out about 40 miles in middle of nowhere late yesterday afternoon on a "mission to check the beer quality in peace & quiet away from it all"....& damn! We still could hear all the booms & bangs from town!! Beer helps!!

Yah, I know the "look" when she surveys my stuff.......but at least she doesn't say much about it:) Got to admit it is a little "out of hand"......ok.....A LOT.
At least we are far enough from "the main road" so neighbors are not a problem. The dogs and the poison oak pretty much takes care of "trespassers" LOL
Come to think of it I haven't been off the property for several weeks....time to visit the "Cat drop box" again" aaaahhhh Retirement:D

Apparently Cat is offering the old style thermostats now at $35-$40 I believe. Guess where they are made.....yup..China!!! so I guess it's good by "Robertshaw" USA.