Terrible mpg when car is cold

**Crasher** · 15-12-2016,12:38 PM

I had to work around one of those systems last week so I could get at the crank speed sensor, as you say, far too complex. Have you studied the coolant temp as seen by the ECU when on a long steady cruise?

**sacha35** · 15-12-2016,05:28 PM

Originally Posted by Crasher

I had to work around one of those systems last week so I could get at the crank speed sensor, as you say, far too complex. Have you studied the coolant temp as seen by the ECU when on a long steady cruise?

As Audi say vous spring technic or as translated how make things more difficult to repair with every new model Audi make. I have studied the coolant temperature logged from the ECU it does somewhat fluctuate as soon as the car slows down or gets stuck in traffic, when cruising it seems to remain around the 85c mark hitting 90c then dropping back which I think is right as 85c was stamped on the thermostat I changed.

What has got me baffled is that the heater gets very hot very quick for a diesel around 5mins and its like toast, this has not changed at all from when I had the car from new ( so possible I could rule out an air leak as the matrix is the highest part so if any air was trapped it would be stuck up in the heater matrix)
The only thing I can think is possible the electric hose thermostat or one of the one way valves in the system have broken causing overflow of the cooling system thus keeping it colder for longer. It just strange that this problem has happened with a camel and water pump change

**Crasher** · 15-12-2016,06:31 PM

Originally Posted by sacha35

What has got me baffled is that the heater gets very hot very quick for a diesel around 5mins and its like toast,

That's part of the idea behind the twin thermostat. You are right though, cars, even ordinary day to day types, are now way to complex for their own good and Audi are the worst of the VAG group, we call them "The four rings of doom". Yesterday we had a Q5 in with both DRL's/sidelights out, it needs £350 of new LED controllers. On this car, if you break one headlight you have to fit a later ones housing which may or may not (according to a twelve odd line dual column left/right interchangeability of components table)... mean you have to do the other side so one broken headlight on an HID/DRL car can mean a £2000 bill, that is simply insane.

**zollaf** · 15-12-2016,06:33 PM

at that price i would be retrofitting some 7'' halogens as used on landrovers, and some cheap chinese drls' . new wires to the battery and a new light switch, less than 150 notes fitted. might not look great but if it saves nearly 2k ???

**sacha35** · 17-12-2016,01:08 PM

Originally Posted by Crasher

That's part of the idea behind the twin thermostat. You are right though, cars, even ordinary day to day types, are now way to complex for their own good and Audi are the worst of the VAG group, we call them "The four rings of doom". Yesterday we had a Q5 in with both DRL's/sidelights out, it needs £350 of new LED controllers. On this car, if you break one headlight you have to fit a later ones housing which may or may not (according to a twelve odd line dual column left/right interchangeability of components table)... mean you have to do the other side so one broken headlight on an HID/DRL car can mean a £2000 bill, that is simply insane.

So would you say I can rule out the hose thermostat as the heater is getting hot and I know I changed and tested the engine thermostat so leaves possible temperature sender, why cant Audi give out test procedures and resistance values or measuring block details. as for the four rings of doom, I have never had any problems with Audi of which I have owned from mid 80s right up until now. The old Audi used to be built like a house and would just keep going, simple to fix and reliable. The cars of today are just getting far to complex, technicians (mechanics) just seem to change parts these days rather than being taught about mechanics, I think if you mention the word white metal bearings to 70% of the mechanics today they would not have a clue.

As you rightly said £2000 for what is a bulb, its getting more than a joke now.

**Crasher** · 17-12-2016,07:33 PM

All that sort of information is now contained in the Guided Fault Finding system section of the VAG diagnostic ODIS package which to get legally you have to jump through hoops of fire to use, I have tried pirated versions and they don't work at at all well, if at all! There is an early 90's Audi 80 type 8A for sale on fleaBay with less than 2K miles on it, those were THE last of of the well built "brick **** house" Audi's, from the A4 reliability went out the window in the sake of chasing BMW and Merc for volume sales and max profit. Better cars to drive in many ways but fragile...

**zollaf** · 17-12-2016,07:34 PM

Audi 80 Barn Find Classic 8350 genuine miles | eBay

car for life. if only we knew then what we know now, that cars would get worse, not better....

**Crasher** · 17-12-2016,10:03 PM

My senior mech showed me that last night as I was just leaving, I was tempted to bid £2K but where would I put it? A 90PS 2L, if you can get the parts (Audi Tradition is a life saver) it would last you forever, seriously strong engine and box, they never ever rust and you could take on a tank and survive. There is one fly in the ointment, if it can get onto classic status it is safe but if it falls foul of the upcoming rules it will be as much use as a paperweight...

**sacha35** · 19-12-2016,09:14 AM

Originally Posted by Crasher

My senior mech showed me that last night as I was just leaving, I was tempted to bid £2K but where would I put it? A 90PS 2L, if you can get the parts (Audi Tradition is a life saver) it would last you forever, seriously strong engine and box, they never ever rust and you could take on a tank and survive. There is one fly in the ointment, if it can get onto classic status it is safe but if it falls foul of the upcoming rules it will be as much use as a paperweight...

Brings back memories, as Zollaf has said if only we knew then what we know now. A couple of my old cars that at the time I did not think anything off and turned out to be worth a fortune today. MK1 Ford Escort 1.6 Mexico, MK1 Ford Escort RS2000, My First Taste of Audi with the original 2.1 L 10v Engine Quattro, great car and even to this day miss it.

I then moved onto updated cars like the Audi 80 1.8e, A4 B5 1.8 20v, A4 B6 2.0 20v and to the present day A4 b8. Little did I know that things would have gotten far worse and more complex than a space rocket to fix.

**zollaf** · 19-12-2016,10:02 AM

amazingly enough, looking on ebay, the 2 escorts and the audi quattro would all be worth about the same amount today, if in really good condition, about 30k each..