Right. I have had a problem recently whereby my car is taking an age to warm up. Getting to work 9 miles and it's not even reaching 70 degrees so I did a lot of hunting round and found a few bits but no guide so thought I would post one up. The pictures were taken after the work so I will explain what's going on. I discovered that our cars have more than one thermostat. Mine is a 2005 dsg model so actually has three. Manuals only have two so as you can guess the third one is for the dsg box. They don't open till engine is up to temp so obviously this will stop the car reaching temp as the flow will not be restricted when cold as VW intended.
Anyway first things first. You need to drain the coolant. Apparently there is a few purpose designed drainage points that tend to break when opened and also are hard to get too. I discovered on an American site (although a long-winded thread the coolant drainage point was very good)
Jack the car and remove the reservoir cap then underneath the car between the sump and the radiator you will see this little gem. Seperate pipe from the unit. (Yellow and red arrows) then leave for the coolant to drain. Obviously it goes without saying leave the car to bee completely cold as red hot water is not nice on the face.
Now that's done we will remove the inline thermostats. First remove the engine cover for more view and access. Starting with the gearbox if you look at the engine between the battery and air intake. You can just about see it in the middle of the picture.
They look like this but black
And zoomed in you can see the stat in the middle of the pic under the plug. Remove the plug then undo the spring clips with mole grips or similar and then you can take the stat out swap and replace. The spring clips can be alkwood depending on which they round they are but all manageable. This one is easy to swap.
Now for the other one infront of the engine. A bit harder to do but not rocket science.
Once you find it it's easy from there.
It's down under the dip stick vertical.
Closer view again
Don't worry about how tight it is you don't need to strip the car back. I discovered an easy way. Underneath the car undo the spring clip for the pipe bellow the stat and seperate then go back above and you will see the metal pipe that comes from the top of the stat. Trace it back to here pointy finger job
Move a pipe and undo this spring clip in the middle of the pic that's rubber pipe on to metal pipe
Now there are two bolts holding the metal pipe on. One is in the middle right of this picture and another one further round towards the front. With this loose, this pipe will come up and out of the way with the stat still attached. It's a little tight to get out and then in but by far the easiest and quickest way. Once it's out change the stat and then reinstall.
Both of mine were open so I could blow through them while cold and I could not close them with mole grips squeezing the life out of them. Well seized open.
Next when the pipes are all back on its time for the coolant. Use G13+ from VW. Nothing else is better and it's not that expensive. The two stats and the two bottles of G13+ were about £60 with trade discount can't really recall the price now. I put one bottle in neat then filled the bottle with tap water (no need for distilled) then tip that in. Next split the next bottle in half with the now empty one and top both up with water. This will have given you 3ltrs of 50/50 in the car and 2 bottles of 50/50 ready mixed. Simples. Now top the car with coolant and then run the engine till it reaches 90. Check the level and then go out and have a drive taking the coolant with you just in case. After a little drive leave it overnight. Check the level and top up.
I had to do this twice to get the level right. Now the car heats to 90 in about 3 miles even in the 5 degree temp.
I have had a few beers so hope this reads ok. Let me know if you need any more info or advice. Or if it's not clear.
