Thermostat and mpg.

[Paul H]

Hi, I'm due a thermostat change, mines clearly stuck open. I'm wondering if this is what's keeping my mpg in the very low 20s.

Even when I'm driving miss daisy I'm hitting 22mpg at best...

Water pump and belts etc will also be done next month, its mot time soon.

2.8 pre facelift btw.

Thx

 

[DrWong]

Greetings from the Toon mate, I'm changing my thermostat today. I get around 25-27mpg in normal driving. Not great haha. Will report back if there's any mpg improvement. Quick google suggests there should be as the engine will be running at the right operating temperature, i.e. more efficient/economical

 

[Paul H]

Thanks Dr, please update with any improvements

 

[Rudyrov]

Theoretically, if you never get to proper operating temp the computer thinks the engine is cold. If the engine is running cold, the fuel system will run rich to help it warm up. The thermostat is a great place to start your troubleshooting and might be the biggest factor. Also worthie of consideration is the oxygen sensor if they are older.

 

[Paul H]

Thx my American friend, incedeltly, I live just a handful of miles from the original Washington UK, the birthplace of your states namesake. The original Washington family home still stands.

I'll also replace the sensor.

 

[DrWong]

Thx my American friend, incedeltly, I live just a handful of miles from the original Washington UK, the birthplace of your states namesake. The original Washington family home still stands.

I'll also replace the sensor.

I also live a only handful of miles from the original Washington, but just from the other direction from @Paul H

Anyway, I didn't get round to doing the stat today. I'm planning on replacing the coolant at the same time, but realised I didn't have a replacement crush washer for the engine coolant plug Need to wait until tomorrow morning to get a washer from local dealer. Hopefully they don't have to order it in

 

[DrWong]

Actually, I just remembered there were some lambda sensor errors stored the last time I connected INPA. Perhaps I should change my sensor too.

 

[Rudyrov]

Glad to be of help my English friends, I had no idea there was a similarly named area in the UK.
Man, you learn something new every day!
Good luck with that cooling system, remember its most likely old and brittle here and there.
Rudy

 

[Lenny b]

In the past a stuck thermostat has always hurt mpg, I am sure fixing it will improve no end

 

[andyglym]

Thx my American friend, incedeltly, I live just a handful of miles from the original Washington UK, the birthplace of your states namesake. The original Washington family home still stands.

I'll also replace the sensor.

but the Washington Hall Fire training Centre was occupied by the USAF in WW2, the original name for the lane was German Lane ......