PDA

View Full Version : Changing thermostat.



routers77
07-01-2008, 01:37 PM
How hard is it to change the thermostat on a 1998 a4 1.8 (non turbo)? Is there any thing to be careful of and are there any special tools that i might need? I will have a go at most things, just want to be sure it is something that someone can have a go at, instead of using a garage. I know the coolant must be drained. It could do with fresh coolant in anyway. Any help is gratefully accepted.

rhencullen1989
07-01-2008, 09:10 PM
Hi, if its the same as the turbo engine (AEB) i changed mine a couple of weeks ago. Not what i would call difficult, just a bit awkward to get to the 2 bolts that hold the thermostat housing on. You need to jack the car up to gain access underneath, remove the bottom undertray (support the car on blocks or similar for your own safety NEVER rely on just the standard jack!!) follow the bottom hose back and you will find the plastic outlet, remove the hose from the outlet and catch the coolant, undo the 2 10mm headed bolts using a spanner, i could not get on mine with a socket. remove the plastic outlet and pull out the thermostat with a pair of long nose pliers,(prepare for more coolant) take note of the position of the o ring, and use a new one on assembly. Assuming you have got the reddy/pink coloured coolant, its up to you to replace or re-use. Dont mix any coolant if you are not sure what it is. Flush the system thoroughly with the thermostat removed if you have anything but red/pink G12+ coolant. Fit new thermostat, o ring and outlet. Fill system, you will have to lift up the reservoire tank to get more pressure on filling, pull back the inlet hose on the heater matrix until the bleed hole is uncovered. Fill with G12+ until it flows from hole, push back hose and tighten. I mixed mine 50/50 with de-ionised water, you will need 2 bottles of G12+ (1.5 litres per bottle) Lastly good luck!!

lonky
07-01-2008, 09:18 PM
perfect description, and yes it is the same on the 1.8 ADR non turbo 20v engine