SuperbTWM

Which engine?

As I said above, I believe if its running and it's just noisy and rattling you can fix by rescuring the casing. Remove the failed rivets and fit some sort of machine scews/studding with nuts/whatever you can make work If its dead then its probably failed electrically

This is because the temp gauge on the dash is programmed to read 'Fast' before it hits operating temp. It will also stay solid at 90 between 70/75 and around 100/110 (I forget the actual values but its basically so the driver doesn't see the real life swings in temperature with engine load, thermostat operating etc.) You will need a scan tool and view the live data of the CTS to get a better idea of the actual temperatures but it looks like its doing a good job regardless

Follow the downpipe from the turbo, access from underneath, you can't miss it

Usually there is just one switch on the gearbox which operates when the car is in any gear (to stop the start/stop from starting the engine when in gear) rather than a switch for every gear. A problem with the switch, linkage or wiring would cause the start/stop issue so sort this out first and maybe the other 'gear selected' issue is just a quirk of this not working correctly.

There is a reader on the steering column where the ignition barrel should be on my Passat, not tried to see if there is one near the start button though.

I've found on pretty much any car there are always things listed that are not correct and it really saves a lot of wasted time and effort if you make sure you know exactly what you need before buying rather than trusting the system to bring parts up with the registration.

It is firing harder to heat cold coolant than warm coolant. Whatever the issue is, maybe it is only present when it is running at higher loads. Sounds to me like the heat exchange is not as efficent as it should be due to a coolant flow restriction or build up on the combustion side causing it to trip out on high temp.

Don't these get noisy due the casing coming apart? I remember fixing one many moons ago for somebody, vaugely remember drilling rivets out and using BA screws and nuts to re-secure and it was good as new

Try unplugging the coolant temp sensor and see if it starts any better.

Have you got a diagnostic tool?

How cold is the ambient when trying to start? What engine do you have?

A car might lock itself after being unlocked and without opening any of the doors. It should never lock if a door has been opened. If it does re-lock after being unlocked and a door has been opened the door microswitch is probably faulty If the car locks randomly on moving the drivers door, it is likely the wiring loom is damaged in the rubber boot somewhere and the car had registered a press on the 'lock' button on the door card.

Even though climate control uses a feedback loop and is totally automatic you will find yourself setting the temperature a lot higher in winter than in summer. Forget the number and just turn it up and down as required to make yourself comfortable.

Not heard of anybody stealing these before, must be a good demand for these units and I imagine the ground clearance is good enough to remove them without raising the vehicle. You will have a challenge heating up the head enough to get solder to stick, filling them with Belzona or Epoxy would probably achieve what you want a lot easier but will of course make life difficult if you want to remove it later down the line.

Can't remember if the A4/Passat has to have the subframe lowered if you want to remove the lower rear suspension arm, the bolt doesn't come all the way out without doing this. That might be the A8 though as I can't remember lowering the subframe, just remember seeing it mentioned somewhere.

Still have nightmares about the one and only time I've had to remove one of these!

The euro 6 TDI does have a few different circuits but AFIAK there are no valves to prevent circulation, it just disables the water pump to allow an electric pump to circulate round the cylinder head, egr coolant and the heater matrix before the mechanical pump gets enabled to pump round the whole circuit including the block, oil cooler and radiator (via the thermostat). I’m sure I’m remember seeing something regarding the 2.0 TSI that mentioned a valve that could divert the coolant rather than using the water pump but I’m not sure if they did the same on the smaller engines

Apologies, got confused with the cars/comments. There is a possibility the mk3 TSI is slightly more complex. Some have extra valves and coolant circuits so depending on where you plumbed it in it may only heat part of the engine such as the cylinder head/ heater matrix rather than the full block. you really need to look at a workshop manual for a definitive answer

There is nothing complicated about the fabia mk1 cooling system, I can't see why it wouldn't work, the thermostat will only open to the radiator once it gets hot enough but I guess the heater thermostat is set lower than the stat anyway. The rest of the cooling circuit remains open all the time AFAIK

Technically speaking the car will tolerate changing tyres on just one axle but in my opinion it is not a good idea to have a large difference like brand new on one end and nearly worn out on the other. These cars are not full time 4WD which is why they don't have a centre differential, but that said, when transmitting torque to the rear wheels the difference in rotational speed between axles may cause 'some' extra stress on the drivetrain. I might be wrong and I may be over cautious but thought I would share my opinion, my opinion may also be wrong so take it with a pinch of salt.

Just go for a test drive in a Ford Diesel and yours will sound like a Rolls Royce in comparison and you will feel much better What is the mileage on your car?

Have you scanned it to see if there are any logged injector codes? Oil ingress into the injector plug and socket and general breakdown of the wiring and connectors under the rocker cover could have caused a misfire.

What does VCDS say?

I I think the main failing here is trying to guess how much oil is in the engine by how much has been removed instead of using the dipstick.