02 4.4 mpg and water

greenvogue · Dec 12, 2009

hi can any one help? i have a 4.4 v8 when i got her it had a water leak on the rad but not that bad so i left it. a week on there was pressure in the hose and tank, had a look and came to the conclusion that it was the thermostate that was not opening, so went and got a new one but did not help so i took the guts out and the car runs great. the temp is always half way and the mpg is about 14.5 around town is this good or bad? but the other day the rad gave up and i put a new one in her, no more water leak but now the temp will only go 1/4 of the way up, in my head i think great as she will neaver get hot and i have hot air all the time so it all ok. but to day i see it only doing abou 10---12 mpg and when sat still 8mpg can any on help.

gegs88 · Dec 13, 2009

put your thermostat back in

gtland · Dec 13, 2009

Gotta agree with that: running cold means running rich, = extra fuel & more engine wear.

rewmer · Dec 13, 2009

put your thermostat back in

As above .

WSLR · Dec 13, 2009

The M62 BMW engine you have uses an electronically controlled thermostat. The issue could be related to this unit. You should be seeing more like 18-20mpg though, so I suspect there are other underlying issues such as oxygen sensors not working correctly. The other thing to remember is that this crap engine has a cooling system held together by o-rings. Overheat these, use the wrong coolant or even look at it funny, and the whole system will start packing up. The engine generally is more resistant to overheating than the Rover V8 but don't allow the system to leak like you have done.

I'd get it to someone with T4 so that they can see what the engine sensors are going and why the car isn't reacing the correct operating temperature.

greenvogue · Dec 13, 2009

Ok thanks for the help but I will have to pay£80 for a new one,and what if it don't open agian or do yo think this was down to the water leak and the rad that it did not open. And why now I have put new rad in it has it only just doing bad mpg , was the old rad naf and full of much that it did not move much water so it stayed hot so the choke was on less? But I can hear the choke go off? Just want to sure that it all adds up many thanks for your help

Datatek · Dec 13, 2009

greenvogue said:
Ok thanks for the help but I will have to pay£80 for a new one,and what if it don't open agian or do yo think this was down to the water leak and the rad that it did not open. And why now I have put new rad in it has it only just doing bad mpg , was the old rad naf and full of much that it did not move much water so it stayed hot so the choke was on less? But I can hear the choke go off? Just want to sure that it all adds up many thanks for your help

New rad = no waterleak = higher system pressure and improved cooling, so now without the stat the engine runs cooler. Cold engine = richer mixture = lower mpg and more engine wear. If stats were not needed, be sure that tight arsed manufacturers would not fit them

There is NO choke on your car, it has electronic fuel injection and a smart box of electronics that adjusts the mixture according to conditions

greenvogue · Dec 13, 2009

Hi I see what you mean but do you think that a new stat will work, is there a way to test the elec wires that send the sig to the stat and at what time should it open

rewmer · Dec 13, 2009

Without knowing the ins and outs of the system, if I was in your shoes and you suspect the thermostat is not operating, I would first off put a meter across the control wires. First with ignition off, second with it on, and then third monitor the reading whilst the engine is running. Although saying that some time spent researching what should be happening, at what tempreture and at what voltage. You may have some luck over on the BMW X5 forums, or try a general M62 engine search.

rewmer · Dec 13, 2009

As an additional, I have found this "Function of the characteristic map thermostat
The characteristic map thermostat is designed such that it opens (engine inlet) at a coolant temperature at the thermostat of 103 o
C without intervention of the integrated heating system. Due to the coolant heating up in the engine, a temperature of approx. 110
o C is measured at the point the coolant flows out of the engine (installation location of coolant temperature sensor for DME and
instrument cluster gauge). This is the operating temperature of the engine, at which the characteristic map thermostat begins to
open without control intervention.
In the event of control intervention by the DME control unit, power (12 V) is applied to the heating element integrated in the
thermostat. Heating the expansion element means that the thermostat now opens at lower coolant temperatures than would be the
case without the additional heating function (thermostat control range: approx. 80 o C - 103 o C)."

Which was an extract from THIS
It would seem that you can just apply 12v to the thermostat to check its operation.
I am now a little wiser to the workings of the L322, I hope you are.

02 4.4 mpg and water

greenvogue

New Member

gegs88

New Member

gtland

Active Member

rewmer

Well-Known Member

WSLR

New Member

greenvogue

New Member

Datatek

Well-Known Member

greenvogue

New Member

rewmer

Well-Known Member

rewmer

Well-Known Member

Similar threads