Just did the heater matrix, and I noticed that the temp needle now slowly drops to zero, then back up to normal, then back down. Its totally random, and not related to engine speed, boost etc. It never reads higher than 'normal'.

What is causing this...?? :(

Check your temperature guage sender for loose connection, also check the sender itself as the spade connector can become loose.

also make sure you have no air in the system.

Does any hot air come out of the heater ? If not then you probably have an airlock as suggested by pk1.

Heater works great :dance:

Where is the sender and spade connector located til I go have a look later...?

If you look at the front of the engine there are 2 pipes coming out of the engine. The upper one will have two connectors going in, one yellow, one black. Its the black one you need to check. Also when you disconnect the black one check the spade is not loose on the sender, if it is you can use a dab of solder to secure it or just replace sender.

It is probably an air lock, you have to raise the front of the car warm the engine up with the rad cap off and fill with coolant when necessary :)

guys while we're on the subjec... my heater matrix is leaking. (I'm, not sure if its the pipes or the actual unit) I was just wondering if there is any way to isolate it until i can get it fixed next month?

guys while we're on the subjec... my heater matrix is leaking. (I'm, not sure if its the pipes or the actual unit) I was just wondering if there is any way to isolate it until i can get it fixed next month?

there is a way type in the search bar on the forum heater matrix by-pass. there has been a few cases of this

 

hth

Lots of people bypass it Wolfman. You should do it soon as you will end up with a footwell full of coolant otherwise. I left mine bypassed but its bloody freezy on cold days when the air blower is on.Dave