SP250 Thermostat

[Crossley Stephenson]

I can't get into the archive today. Can someone tell me the correct thermostat to use in my SP250.

Thanks
Michael

[John-B]

David Manners has them, http://www.jagspares.co.uk/Manners/part ... tno=C3731S tel. +44 (0) 121 544 4040 for spec.

I think you can use various cut-in temperature models depending on what you want and where you run your car (ie hot or cold countries).

Phil Glennerster when restoring my engine used 76 degree C (169 F) model, but some people use a higher temp. model. You can also get fail-open or fail-closed models. Fail-open is obviously safer but I don't think mine is.

The old archive was online about half an hour ago, I'm sorry it's so flaky, I emailed bakerp about it yesterday as it really must be sorted.

Are you going to use AIT (inorganic) or OAT (organic) coolant? I'm using blue anti-freeze from Halfords which is inorganic (I think). Read this: http://www.da7c.co.uk/technical_torque_ ... freeze.htm

[Dig-SP]

From the manual 76d

[Phillmore]

Are you going to use AIT (inorganic) or OAT (organic) coolant? I'm using blue anti-freeze from Halfords which is inorganic (I think). Read this: http://www.da7c.co.uk/technical_torque_ ... freeze.htm

I believe that Halfords blue is not the original blue our old systems need. I did some research a while ago and went for Holden's "Alpine Anti Freeze BT Blue" made by Millers. Conveniently Holden's are only a ten minute drive from me.

[Crossley Stephenson]

But what thermostats are being used......?

Michael

[David S]

Thermostats are sorted now from Digby's print of the Manual's page.
Now what about Anti-Freeze...
On the bottle, the blue stuff apparently offers 2 years corrosion protection and I believe the frost protection is much longer, but Central Heating corrosion inhibitor lasts forever, so why not use that with 20% Anti-Freeze?
The central heating materials are the same as the car's: Cast Iron = House Radiators & Car Cyl block; Aluminium = House C/H Heat Exchanger & Car Cylinder Heads; and Copper = House Pipes & Car Radiator.

[Crossley Stephenson]

With respect David, thermostats are not sorted and if you want to talk about antifreeze start your own post.

I am interested in what thermostats people are using NOT the thermostat recommended by Daimler, I can read that in the manual. The climate here is somewhat warmer than UK (one of the reasons I left) and I want to know if others use a different thermostat to account for the warmer temps.

Cheers
Michael

[Ian Slade]

Though the climate is warmer, that doesn't change the thermostat settings, though it may change the design, the idea of a thermostat is to heat the engine to a known temperature and then open and close it to hold that temperature, unless one can find a thermostat that can give a higher flow when open and the airflow through the radiator is at the optimum, there is not actually much one can do. The SP was designed for the US market where summer southern states temperatures reach very similar temperatures to Australia. The size of the unit is fixed due to the housing, whether there is a higher flow version now that will fit would be down to checking thermostat specifications. The SP has always had a problem in producing optimum flow of air through the radiator in low speed situations, the original fan being useless in traffic, I would suggest that it may be more successful to optimise the the airflow through the radiator.

[Crossley Stephenson]

OK, my concern is that on warm days (28-32c) at highway speeds (100-110kph) the temp gauge (after a while) registers over the white band 'normal' range but only about half way between there and the 230 (obviously hot) and the electric fan (R&P conversion) holds it there. I keep getting told the electric fan should not come on at highway speeds; is this correct. The thermostat controls coolant flow and I want to UNDERSTAND what is going on.

Cheers,
Michael

[Crossley Stephenson]

And BTW, John-B, phill more,DavidS and Ian,

What thermostat do you use?

Cheers,
Michael