TR2/3/3A Moss original sleeved thermostats for TR3

[karls59tr]

Anyone running one of these? I have been running a plug in the bypass hole with a 1/8 hole drilled in the plug. I did blow a bypass hose last summer but it may have been due to age. Is this new Moss thermostat a better way to go? Around $75 Incidently the temp gauge(which went to higher temp when tested in a pot of boiling water) failed to indicate the higher temperature when the bypass blew! It was only upon checking the rad that I realized I had lost a huge amount of coolant. Karl

 

[Don Elliott]

Karl - The sleeved Thermostat automatically blocks off the bypass so if yours is blocked off now and you have no overheat problems, don't "fix" it "if it ain't broke"!

Somewhere on another TR forum a chap writes, "If it ain't broke, fix it till you break it".

 

[Geo Hahn]

I suppose one possible advantage to the sleeved style is that it might get the coolant warmed up faster on a cold day (and thus the heater heating).

I'll let you Canadians think about that as a chilly day down here is anytime the temp dips below 70F.

 

[TomMull]

"the temp gauge(which went to higher temp when tested in a pot of boiling water) failed to indicate the higher temperature when the bypass blew!"

Sometimes the temp gauge fails to register the true water temp when the level falls below the bulb and the system has not yet started producing copious amounts of steam. Just not enough heat transfer with air I'm guessing. Tom

 

[SkinnedKnuckles]

Sounds quite reasonable, Tom. Another thing is the transmitter (sending unit) is not quite right.

 

[Geo Hahn]

Tom's explanation conforms with what I have observed.

TR3s do not have temp sending units per se -- the capillary tube is a direct physical measurement of the temparature at the bulb (inside the tstat housing).

 

[TR3driver]

TR3s do not have temp sending units per se -- the capillary tube is a direct physical measurement of the temparature at the bulb (inside the tstat housing).

Toe-may-toe, Toe-ma-toe ... the bulb in the thermostat housing translates temperature to pressure, and the pressure is carried by the "capillary" tube to the gauge (which is a Bourdon tube pressure gauge).

Main difference is that you can't see the smoke when it leaks out!

 

[mrv8q]

Anyone running one of these? Around $75

Yikes! I bought 2 from MOSS six years ago when I first got my '3; about $35 each as I recall.
Never any problem w/ them; I gave it the boiling water in the pan test, and it passed....

 

[TR3driver]

I suppose one possible advantage to the sleeved style is that it might get the coolant warmed up faster on a cold day (and thus the heater heating).

Seems to me that would only be true if you have also drilled holes in the thermostat plate (as I do). The heater is partially in parallel with the bypass, so restricting the bypass should force more water through the heater core.

Also worth noting that the factory later went to a smaller bypass passage and a non-sleeved thermostat, around the introduction of the TR4 as I recall.

Not sure, but I believe those cheap sleeved thermostats from Moss were a different design, essentially a sleeve added onto a wax pellet type thermostat; instead of a reproduction of the original bellows (aneroid) thermostat.

 

[Bob_Muzio]

Randall, the TR4 also uses the sleeved stat.
I've run the car both ways and, as we're in SoCal, I never noticed a difference with an operational or non operational by pass in warm up.
Bob

 

[mrv8q]

Bob, how's your new car coming along?

 

[TR3driver]

Randall, the TR4 also uses the sleeved stat.

Yup, I misremembered. The TR4A used a non-sleeved stat (140970). Curiously enough though, it used the same housing and bypass as the TR4.

 

[Bob_Muzio]

Hi Kevin,
The new one is progressing nicely. You need to stop by Paty's sometime to see it. If you email me first I'll let you know if I'll be there with the TR.
Bob

 

[ekamm]

I have a curiosity question. My '59 3 appears to have no thermostat (temp. rises steadily finds 185 and stays there as long as I'm moving.). Is this common? why do it? and should I change it and what to?

 

[Twosheds]

I have a curiosity question. My '59 3 appears to have no thermostat (temp. rises steadily finds 185 and stays there as long as I'm moving.). Is this common? why do it? and should I change it and what to?

Don't touch it!

 

[Geo Hahn]

I have a curiosity question. My '59 3 appears to have no thermostat...

If you mean you have opened the tstat housing and it is empty, than that is odd.

Otherwise, what you describe is exactly how the temp should behave with a properly operating thermostat. The thermostat controls the lower end of the temperature spectrum, the cooling system (radiator) controls the upper end -- when both are okay they strike a balance at the ideal operating temperature for the engine.

 

[ekamm]

I understand how it works but with a normal thermostatically controlled system. The temp. heats to the point that the thermostat opens and you see the gauge go a little over that mark. When cooler water is introduced with the stat open the gauge drops and slowly rises to the operating temp. With my system you can't see the point where the thermostat opens. And no I haven't and don't really plan on opening it up.

 

[TR3driver]

I understand how it works but with a normal thermostatically controlled system. The temp. heats to the point that the thermostat opens and you see the gauge go a little over that mark. When cooler water is introduced with the stat open the gauge drops and slowly rises to the operating temp. With my system you can't see the point where the thermostat opens. And no I haven't and don't really plan on opening it up.

Just a matter of how fast the thermostat opens. If it cracks open slowly enough, the cooler water from the radiator is heated by the time it gets back to the temp gauge pickup (which is at the outlet from the engine).