thermostat

[sean sherry]

An 87% Thermostat for a 280 - 110 - '80's Is this correct ? Car came with a 70% which I replaced with a 82%. As the sensor for the Electric Fan is set at 100% maybe 87 % is correct for the car, as I've been advised.
If so it may cause the Air Valve to respond sooner. A bonus.

 

[Helmet]

An 87% Thermostat for a 280 - 110 - '80's Is this correct ? Car came with a 70% which I replaced with a 82%. As the sensor for the Electric Fan is set at 100% maybe 87 % is correct for the car, as I've been advised.
If so it may cause the Air Valve to respond sooner. A bonus.

Yes, from the factory it would have come with an 87°C thermostat.

 

[sean sherry]

Thanks Helmet, I bit the bullet and fitted an eighty seven today.
Temp. now sits steady at that Temp. and even though I have a 90% fan sensor switch it does not kick in.
So the thermostat is doing its job setting a floor temp and the radiator is taking care of an upper Temp.


I'm off to Brisbane tomorrow and with 40 pounds COLD in the new Michelins, the old 107- 280 SL should be happy on the open Road.

 

[Helmet]

Thanks Helmet, I bit the bullet and fitted an eighty seven today.
Temp. now sits steady at that Temp. and even though I have a 90% fan sensor switch it does not kick in.
So the thermostat is doing its job setting a floor temp and the radiator is taking care of an upper Temp.


I'm off to Brisbane tomorrow and with 40 pounds COLD in the new Michelins, the old 107- 280 SL should be happy on the open Road.

With 40psi you will have a very bumpy ride , 30psi would be more comfortable

 

[Michel]

With 40psi you will have a very bumpy ride , 30psi would be more comfortable

At 40 you would save some fuel and tyre wear, but sacrifice the ride

 

[SEL_69L]

With hard tyres, you also chop out the suspension bushings a little more quickly.

I find that for my 6.9, 36 psi gives the most even tyre wear, although 32 psi is reccommended on the tyre pressure placard. Perhaps 34 psi would be the best median pressure. I am getting some new tyres soon, so I might run with 34 psi, instead of 36.

Just remember, there is an awfully big chunk of cast iron over those front wheels. They have to do a lot of work. Helps to explain why cast iron engines were never used by Merecedes again, or for other manufacturers, either.

 

[sean sherry]

Yes, dropped the pressures to 36 in Brisbane. The 110 engine likes the 87% thermostat. Very hot in Queensland , Temp was very stable around the 87 to 90 even stuck in Traffic. I'll swear Brisbane Traffic is now worse than Sydney. ....... Sean

 

[Styria]

Yes, dropped the pressures to 36 in Brisbane. The 110 engine likes the 87% thermostat. Very hot in Queensland , Temp was very stable around the 87 to 90 even stuck in Traffic. I'll swear Brisbane Traffic is now worse than Sydney. ....... Sean

Sean, you're kidding - could Brisbane traffic be worse than Sydney ? I have almost given up using the car on Saturdays - roads are choked everywhere you turn, unless you get going early in the mornings. I was quite interested in your observations on the 87degree thermostat - it is of course the correct specification to use, and it is the same as to what is specified for the 6.9s. Mind you, the other day I did fit a 79 degree unit to SEL 69L's car as on hot days the temperature would ever so steadily increase to about 100, and David was concerned about possible overheating issues. Mind you, a friend of mine also has a 6.9 and he maintains that you can run a 6.9 all day at a hundred and not cause damage to the internals of the engine.

Interestingly however, 450s are fitted with a 79 degree thermostat from factory,but at one stage I tried a 87 unit, but the car did not like it as it started to overheat. BTW Sean, I am hoping that you will be able to attend our get together on the 9th June at Anthony and Karen's. Regards Styria

 

[sean sherry]

What I can't get my head around is how a lower value Thermostat would stop over heating , as once the thermostat is open it is all down to the Radiator and the water circulation. My understanding is that the Thermostats job is to put a floor on the minimum Temp.so that the engine will not run too cold.
Sure, an early opening Thermostat would give the Radiator a head start but after that the cooling system is on its own. ? ? Sean

 

[Styria]

What I can't get my head around is how a lower value Thermostat would stop over heating , as once the thermostat is open it is all down to the Radiator and the water circulation. My understanding is that the Thermostats job is to put a floor on the minimum Temp.so that the engine will not run too cold.
Sure, an early opening Thermostat would give the Radiator a head start but after that the cooling system is on its own. ? ? Sean

Sean, all of your statements and reasoning are spot on. The fitting of the 79 degree thermostat did in fact keep the temperature lower for a certain period of time, but once under way for an extended period, the lower degree thermostat lost its effectiveness. Hence, the creation of my Water Pump post - that work as a direct result of performing fairly major surgery on the cooling system. Regards Styria

 

[sean sherry]

May I respectively suggest that overheating with a 80-87% thermostat tells me that there is a problem with the cooling system. Either circulation or Coolant capacity. Manufactures fit the smallest ( lest costly) Radiator they can get away with. Also restricted air flow to appease the designer of the front end. Add to that the design of the Cyl. head which "may " have hot spots around the exhaust valves that are not cooled effectively because the coolant is not transferring the excess heat to the Radiator. In such engines "Red Line Water Wetter " has been proven to alleviate this. Apparently it's the only product that works.
Running an engine too cool kills performance , i.e., restricts gas expansion, ( Less shove for the Piston. ) and increases fuel consumption.
E.G., Remember Standard Vanguards ,!950s, with 70% thermostats from Factory ? We fitted an 80 % and fuel consumption dropped by 2 or 3 MPG..

I have learnt the hard way.... Sean

 

[Helmet]

Remember Standard Vanguards

No

 

[sean sherry]

Obviously you are much too young Helmet ! Being pre War myself ( 2nd W/W ) a lot of water has flowed under the bridge.....Sean

 

[CraigS]

As a car, they made a great tractor !

 

[sean sherry]

You are on the right track Craig. The engine was used in the Ferguson Tractor, designed in Belfast and manufactured by The Standard Motor Company in Coventry The " Fergi " Tractors are still going strong around the World but the Vanguards faded away. Sean