How hot should my car run at?

[Norfolkandchance]

Our W245 B200 Turbo only gets up to about 60 Celsius, often less (assuming the gauge works properly). The heater is fine but nothing special. It has plenty of water, by the way. Is 60 normal? it feels like 80, straight up on the dial, would be more usual.

Thanks

ps apologies for terrible grammar in the title - I don't seem to be able to edit it.

[Happy Jim]

60 is way too low for any car, best check it with an IR thermometer if you can find one (just to confirm whether the guage is correct or it’s a false reading).

Jim

[eldar]

Yup, 60c is too low. Could be the thermostat, could be the gauge.

Get a bluetooth adapter for the car and the Torque app (or similar) and see what the real coolant temp is. If 60c, then thermostat.

[r129sl]

It is overwhelmingly likely to be the thermostat and not the gauge that is bad.

[gizlaroc]

89ºc is where yours is meant to be.

How old is the car? 'Stats usually fail around year 5.

I bet your mpg is quite poor if it is not getting up to temperature?
The ECU uses the value from the 'stat to know how much fuel to mix.

[Happy Jim]

gizlaroc said:

89ºc is where yours is meant to be.

How old is the car? 'Stats usually fail around year 5.

I bet your mpg is quite poor if it is not getting up to temperature?
The ECU uses the value from the 'stat to know how much fuel to mix.

Nope, stat opens or closes to allow water flow towards the radiator, it aims to open/close to keep water temp at ~90 Centrigrade.

There is separately a water temp sender that supplies the ECU with the info, ECU will then (probably) have some under/over temp fuelling strategy.

Jim

[gizlaroc]

Happy Jim said:

Nope, stat opens or closes to allow water flow towards the radiator, it aims to open/close to keep water temp at ~90 Centrigrade.

There is separately a water temp sender that supplies the ECU with the info, ECU will then (probably) have some under/over temp fuelling strategy.

Jim

Yeah, I get that there is a temp sensor that gives the reading, but if the thermostat is not working and the car is never getting to 90ºc it will be overfuelling.

There was a good article explaining how Mercedes work out the MPG on the OBC, it showed the 'maths' used to calculate it and showed how it was overfuelling by some 40% when cold and how that changed as it reached temperature.

Surely it is just a modern day choke?

[eldar]

gizlaroc said:

Yeah, I get that there is a temp sensor that gives the reading, but if the thermostat is not working and the car is never getting to 90ºc it will be overfuelling.

There was a good article explaining how Mercedes work out the MPG on the OBC, it showed the 'maths' used to calculate it and showed how it was overfuelling by some 40% when cold and how that changed as it reached temperature.

Surely it is just a modern day choke?

Yup, a modern day choke, slightly smarter than the pull out handbag hangers. The ECU is easy enough to interrogate to find out the coolant sensor reading and cross check with an IR thermometer. 95% likely a failed or sticking thermostat.

[Norfolkandchance]

Thanks for all the replies. According to the internet it looks like a pain to change!

[Norfolkandchance]

Got caught I traffic the other day. unusual for me. Gauge went up to 80 and hovered around there, then went down when we got going again. Makes me even more clear that it is thermostat.

[GlenMH]

Norfolkandchance said:

Got caught I traffic the other day. unusual for me. Gauge went up to 80 and hovered around there, then went down when we got going again. Makes me even more clear that it is thermostat.

I have recently discovered that the thermostat on my E320CDI has been FUBAR for at least 8 YEARS.... :O

I now have lots of lovely warm air and the engine gets warm in about 20 minutes compared with over an hour before....