Latest Gremlins - Coolant temperatue sensor loom.

[SammoVWT]

Been having an intermittent idle/warm running issue where its almost like a misfire more noticeable when cooling fan was coming on/off. Only ever happened when the car was at temperature.

Replaced my ignition switch a few days ago as it was starting to fail, producing some spectacular results on the motorway recently.

Eitherway, down to business - symptoms seemed eerily similar to a faulty CTS, but the temperatures were reading more or less correct. Decided since my rocker cover gasket has seen better days that I would clean up the plug incase any of the old seeped oil had run inside and was causing me issues.

Cleaned up with a combination of carb cleaner and contact spray inside sensor plug and plug harness - made some improvement, but I wasn't happy.

Cleaned up all the road dirt and grime off the back of the CTS harness (socket) which has been caked on for years (used an old toothbrush with cleaners sprayed on to bristles). Low and behold I found my issue - broken wiring insulation, so all that filth/carbon was upsetting my CTS reading to the ECU (dash loop is OK).

It's a good job I like this car - another head-scratcher solved.

Ideally I would like to re-pin a new plug for this CTS, but I don't even know where to start for a new one. So for now, more contact cleaner on the exposed copper, dried and taped. Problem solved - so just a bit of a heads-up for anyone else with an old mk3! Upside is that the exhaust has lost its hint of richness I was getting occasionally.

[Col]

Glad to hear you are still running the old girl.

Small niggles are to be expected. How old exactly is the old girl ?

[SammoVWT]

18 years old now - still plenty of poke in the engine. I just need the niggles to stop so I can get onto the body work, lol.

Still got an electric window to fix, and sort out the rear wiper motor, other than that it's alright!