Can anyone suggest cause(S).  Car is 1.6 diesel 2015 and has done 140K . I bought it cheap from a garage "as seen" and have done 20K in 6 months more or less trouble free but I expected trouble. My guess is that the car has had major problems and possibly been in front end smash. Work has been done on it by someone who may well be a fine fellow but a rotten mechanic. e.g. it looks like the injectors had been taken out but refitted using old seals which were leaking and there was a clamp missing on the turbo air intake which meant that it sounded like a trumpet when I put the boot down.

Car has an aux water pump I think (Is this standard)

 

1.Car uses about 1 pint every 1000 miles or so. Never seen any sign of a leak but this might have nothing to do with the rest of the problem  

2. Temp gauge rarely gets above 60. If I leave the engine running, and not driving it will go up to 90 and the cooling fan kicks in until it drops to 80

3.In Car heater  never gets really hot (and winter is coming!)

4. If the car temp is at 60-70 and I switch engine off the temp rises slightly then starts to fall

5. Diesel consumption is getting worse as the outside temp is going down. Early in the day it can be as low as 35mpg. I had been getting well over 60/70 on motorways in the summer and 60+ in mixed driving.

 

I can't work out if the temp sensor is faulty or the thermostat is jamming open sometimes and pumping water through the radiator all the time or if something else is causing problem.  Is the thermostat driven by coolant temp alone  or does the sensor or EMU get involved in opening or shutting it?  It seems to me that some of the functions are working but not all. 

 

 

Hello Neil.

 

Worth a read:

 

Thermostat open is a likely candidate. CTS readings too.  Worth scanning for error codes to see if there's anything obvious.

 

Gaz

 

1. Head gasket and/or faulty cylinder head or oil cooler, or egr cooler.

2. If (1) is not head gasket, then it could be water pump fault.

3. Headgasket/cylinder head, or water pump, or blocked heater matrix.

4. Probably heat soak from engine warming the coolant.

5. Probably linked to running cool.

I think the thermostats are just standard type, as in no electrics, so reasonably easy and cheap for a first shot.

 

IMHO that sounds like a thermostat issue. One of my previous tranny van had a stuck open thermostat and it pretty much done what you've described; never got up to temperature, drank diesel like it was going out of fashion and the heaters could only blow out luke warm air. It always ran a high idle as well.

 

Have you any info on when the pump / coolant was last changed? Just in case there's any crud which may have stuck it open.

Edited 15 November, 20196 yr by tunedude