Thermostat bypass restrictor (or not)

[4flattires]

So I am sorting out my 109 issues prior to firing that thing up for the first time in 25 years (it's new to me). Many issues are completed and behind me, however I have dug into the cooling system today and glad I did. Surprisingly, it held 6lbs with the pressure tester and some water, but the hoses were harder than rock hard, and needed to come off. By the way, heat guns do a great job of softening up those hoses for easy removal.

It had a flat style thermostat, but no restrictor gasket, heck it didnt even have flow past the stat.

Is this housing the new style that uses the flat stat?

http://www.roversnorth.com/c-44-thermostat.aspx

Seems the pic resembles the skirted style tstat. Those stat prices are making me think they are the skirted style (not sure why they would be that expensive)

[mearstrae]

Wow! That hose would make me worry about the passages in the engine and radiator. And what does the thermostat housing look like? The wax filled (expensive) thermostat is stock and I don't think that a flat style (like american engines use) would/should work in that housing. The stock ones use internal melting wax (!?) to open at a given temp, and the flat ones use a spring and copper slug to do the same, when heat hits them.

'95 R.R.C. Lwb
'76 Series III Hybrid 109
'70 Rover 3500S

[disco2hse]

Seconding above.

I would certainly look at having the engine pressure flushed with appropriate chemical cocktails, and also rodding the radiator. It is probably full of muck too.

Thermostat for Series IIa is the same for III. They are not expensive. Look for part numbers 74ºC 532453 and 82ºC 596225. The O ring is 527235. Shop around, e.g. http://www.lrseries.com/shop/product...=532453&page=1

[4flattires]

I've definitely got the flushing squared away.

@mearstrae, the two stats will physically fit, but do perform significantly differently. There are write-ups out there citing the differences.

Alan, thanks for that source on the stat. A significant savings there. My preference is to stay with the skirted style (no pun intended).

:-)