Not sure if I need to replace my Coolant Thermostat on my 2001 ALH Golf (un modified) .....
It all started when I was fettling the injection timing following Timing belt replacement and I thought the car was struggling to get over 80 deg C.
VCDS Block 7 logging reports warmed up temperature (G62) between 76.5 and 84 deg C. With most of the time around 80 deg C. Logging started at 15 mins in after starting my journey. This feels a bit low to me. New thermostats (044 121 113) say they open at 87 deg C. Does this mean they start to open or are fully open at 87 ??
External temperture according to Dashboard was just below freezing between -2 to 0 deg C through the journey.
G81 Fuel intake temp was between 20 to 28 deg C in the same period and similarly G72 Air Intake was between 3.6 and 8 deg whilst moving. The Air Intake temp rose as I came to a standstill to 12 deg as expected.
This was recorded over a 55 mile (just over an hour) journey all on motorway (highway) at 60 mph, approx 2000 rpm 5th gear. The car returned 68mpg (UK gallons) and has always historically returned this sort of good mileage from new 11 years ago. Its now done 200k miles.
Question : Do I need to replace the thermostat, is it really worth disturbing it ? On one hand, my engineering experience says, if it works well - why change it ? Equally - like many of you, I like to optimise for fuel efficiency in this age of rapidly rising diesel prices ? What realy mpg difference will 5 to 10 deg make ?
Many thanks!
It all started when I was fettling the injection timing following Timing belt replacement and I thought the car was struggling to get over 80 deg C.
VCDS Block 7 logging reports warmed up temperature (G62) between 76.5 and 84 deg C. With most of the time around 80 deg C. Logging started at 15 mins in after starting my journey. This feels a bit low to me. New thermostats (044 121 113) say they open at 87 deg C. Does this mean they start to open or are fully open at 87 ??
External temperture according to Dashboard was just below freezing between -2 to 0 deg C through the journey.
G81 Fuel intake temp was between 20 to 28 deg C in the same period and similarly G72 Air Intake was between 3.6 and 8 deg whilst moving. The Air Intake temp rose as I came to a standstill to 12 deg as expected.
This was recorded over a 55 mile (just over an hour) journey all on motorway (highway) at 60 mph, approx 2000 rpm 5th gear. The car returned 68mpg (UK gallons) and has always historically returned this sort of good mileage from new 11 years ago. Its now done 200k miles.
Question : Do I need to replace the thermostat, is it really worth disturbing it ? On one hand, my engineering experience says, if it works well - why change it ? Equally - like many of you, I like to optimise for fuel efficiency in this age of rapidly rising diesel prices ? What realy mpg difference will 5 to 10 deg make ?
Many thanks!