new member question

[Jim's 64 FHC]

Hi all. I did intro myself in new member area.

I don't want to beat a dead horse on this question.. I have searched, and read enough to make my brain hurt. And I don't want to start a big debate. The question.....The $40 thermostat, the major sellers sell. Does it work? And the $130 bellows type they sell, Does it work? I'm getting ready flush cooling system, and would like to put proper one in. 64 3.8 xke.

[bitsobrits]

Go to coolcatcorp.com and read all about thermostats there. Plenty of information to make an informed choice.

[mgcjag]

Hi jim...no simple yes/no answer so you need to decide for yourself......the £130 ones(from Moss) look the part but are reproductions....i know some that have fitted them but not long enough to know how good they are...here is the cool cat info https://www.coolcatcorp.com/thermostats ... ifold.html

[DWW]

Not being a mechanic by any stretch of imagination I never thought or realised the complexity and science behind the choice of thermostat, mind boggling it is too. up to now a thermostat was a thermostat, choice between winter or summer, bellows or not. I am not sure what type is installed in mine but I know it ran reliably and steadily temp wise in the hottest days of last summer and the coldest day at present.

[mtnjag]

If the original style thermostat from Moss is correct it will aid in cooling. The simple reason is when the sleeve style thermostat opens at temp it’s sleeve blocks the coolant bypass from the manifold to the waterpump. Look into your thermostat cavity and you see the bypass slit, pretty good size.

The bypass is there to aid warmup by directing warmed coolant from the eng directly to the pump and back into the eng, thereby aiding warmup. That happens when the orig style thermostat is closed and the slit is not blocked.

When warmed up to rated temp, thermostat opens, slides down, and blocks the bypass and directs all coolant to the radiator for optimum cooling.

Without the sleeve design some hot coolant will always be allowed to re-enter the engine without seeing the radiator. Better cooling efficiency with the proper thermostat.

I have a sleeve style thermostat in my 3.8 but it went in 25 years ago and it may or may not have come from XKs Unltd who was purchased by Moss. I have no idea if its the same as Moss is selling. Still working well though.

No endorsement but Welsh sells one for $40.