Coolant temperature issues

[Rallycoach]

Hi guys,

Have just purchased my first roadster and love it however it has a niggle.

When driving at any speed the temp sits happy around 80-85 deg which seems normal however when I stop at a set of lights or get held in traffic I get a steady increase in temp to +110 and at the same time cold air from the heater I guess is an airlock. As soon as I move again the temp comes down and the hot air returns to the heater.

The water pump and belt are new
The level in the expansion tank never changes
The car drives lovely
No changes to the temp when driven hard on boost and no loss of coolant.
The rad fan works
The rad isn’t blocked
Not sure the thermostat would give these symptoms.

Do I just have an airlock to bleed out or something more sinister?

I am not yet familiar with the systems on this car but am capable mechanicaly.

Thinking airlock or HG?

I have bled the system via the rad bleed point with the car jacked, should I try the temp sensor method too?

If it’s HG it’s odd that I am loosing no fluid especially on boost.

Many thanks in advance

Iain

[Thrumbleux]

When driving at any speed the temp sits happy around 80-85 deg

Not HG.

I have bled the system via the rad bleed point with the car jacked, should I try the temp sensor method too?

Yes.

[Rallycoach]

Thank you, I will try the bleed later today.

[tolsen]

I believe there is no need to bleed coolant at engine end by lifting coolant temperaure sensor since the Roadster has its expansion tank at the rear situated higher than engine.

Bleeding a Roadster like a Smart Fortwo cannot do any harm but I would simply bleed at radiator end whilst engine is running cold at fast idle with expansion tank cap off.

[BBE]

I fully agree with Tolsen on this.
I have replaced the coolant in my RCR several times, and all I ever did to bleed it
was bleeding at the radiator with open expansion tank. Allways at level ground.
Bjorn

[Thrumbleux]

When I answered 'yes', it was on the basis that given it takes nothing more than a minute to do, it's worth doing.
Obviously there are slight differences between the 450 and Roadster cooling systems - at last, a real reason to recommend TRN.....

[137699]

Hi "Rallycoach" - congrats on buying a roadster.
For the best help and advice with these unique cars you'll find the Smart Roadster specific forum (www.theroadster.net) the best place for advice on these beasties.

Enjoy!

[137699]

Hi "Rallycoach" - congrats on buying a roadster.
For the best help and advice with these unique cars you'll find the Smart Roadster specific forum (www.theroadster.net) the best place for advice on these beasties.

Enjoy!