I have a 6 year old Ibiza with low miles on it but not long after I had the aircon refilled I have had an ongoing coolant problem - the 2 may not be connected as the timing may just be a coincidence. I want to see if anyone had any ideas before I give the dealer my dosh

I had an 'EPC' light come on in my car plus the engine management light so got myself one of those scanners off ebay. Whilst waiting for the scanner the car was still being driven and sometimes the lights would come on and other times they wouldnt. Also there was no pattern to when they would light up e.g. engine at certain temperature, sitting in traffic.

When the scanner arrived I was able to discover the code fault which gave the issue of 'Engine Coolant Temperature Circuit Range/Performance Problem' - a quick search on the net indicated that the sensor on seats/VWs are prone to failure so I replaced this myself (dealer was quoting £80 when the part was only £35!!!).

Since replacing the sensor the engine light stays off but the 'EPC' light comes on randomly. Having plugged in the scanner again I am getting no error codes so dont know where the problme may be.

At the same time I have been monitoring my coolant level and it has been dropping but I cant trace where it has gone to - there are no puddles on the drive and the oil appears fine. Also the engine temp has been fine throughout the whole time

any ideas what else i could look at ?

cheers

It could be just trapped air -- or a minor leak that will only show with a pressure test when the engine is cold.
You can build a pressure tester using a pump up garden sprayer and use a plastic tee connect into the pipe between the engine or rad and the car's expansion bottle. Fill the sprayer with coolant and pump ups the system to just below the pressure the pressure cap lifts.
Doing a cold presure test is the only way to find very minor leaks as when hot the leak instantly flashes off to steam which is invisible.


As to fault codes you really need to scan with a code reader or pc interface that will read live data, freeze frame & pending codes. I use a Memoscan U581 (about 65 quid off ebay) for this however for VW group cars lots of cheap scanners and interfaces are available for just a few quid more that give near dealer level access (for example Memoscan U585 see http://www.autotec-direct.com/memoscan-u585-vwaudican-obd2-scanner-716-p.asp)

[Edited on 19/7/09 by britishtrident]

Just done headgasket on my girlfirends clio for a "missing coolant" isssue.

Originally though it was waterpump leaking as these are common, but after finding a new pump on there I took the head off and found it had split between no. 4 cylinder and a water hole at the gearbox end.

Shaun