The coolant level goes down over time which is an issue I knew about when I got the car and apparently it has done this for a while. Previous owner had the misfortune of finding a crap garage which replaced the water pump (I am guessing it didn't even need replacing myself), used some sort of gasket adhesive gunk, and put blue coolant in I am unable to detect any leaks in the coolant system, but I guess it could be a difficult to find one.

There was plenty of mayo on the underside of the oil cap, which I thought could have been due to short journeys and the oil not being changed as often as it should. I have since removed the engine cover and now use the spare oil cap. Used a flushing oil fast idle 10 mins, a cheap plain oil for about 5 mins to flush out the flushing oil, and put in new good stuff. I had hoped if there was any water left in the oil that doing this would have removed it. The mayo is coming back a little after 60 miles, although I haven't been able to detect a loss of coolant as yet, but the coolant is difficult to see through the tank. I am not sure if what's inside the expansion tank/cap is oily film or coolant droplets (I tried rubbing it between my fingers and it doesn't feel particularly oily). I can't smell anything tell-tale in the coolant but then my sense of smell isn't great. There's nothing more than the usual condensation coming out of the exhaust. There's no evidence of overheating or rough running other than is normal for this engine (at idle), although if I interpreted the code numbers right from the shareware version of VAG-COM a misfire was detected at some point on cylinder 1. I have read this guide http://reviews.ebay.co.uk/HOW-TO-TEST-FOR-A-FAILED-HEAD-GASKET_W0QQugidZ10000000001891247 and tried the squeezing the top hose thing while opening the expansion tank cap, and I get more of a pop bottle opening effect than a gushing of water.

I will try and give the cooling system a good going over (still has wrong coolant in there). I believe the temp sender and thermostat need replacing so will do those. Will also replace the original hose clips for jubilee ones if I can reach them. Change the coolant bottle and cap. Ensure there is a washer on the rad fan switch (posts here suggest one wasn't fitted at factory and it is a common leak spot), and give the system a good flush through, then fill her up with g12 spec and deionised water.

Being the 8v I am concerned the head gasket may have had it. Is there a sure fire way to detect if the head gasket is on it's way out before going over the coolant system? (I figure it would be best to get HG sorted first as that involves draining the coolant anyway).

It's a 2002 and has first 3 years dealer service history although no mention of hg in there.

Thanks in advance.

Edited 19 February, 201016 yr by anewman

Take it to a garage for a coolant sniffer test.

This is what the drained oil looked like. I think the bubbles are just air from pouring. Oil shown on paper so colour can be seen. It's nowhere near the colour of the HG failed oil in the lower picture. Will go to a garage for a sniffer test in near future and report the results.

My drained oil.

Edited 4 March, 201016 yr by anewman

Test done no exhaust gas in coolant. Garage suggested mayo could in part be due to the emissions control system (with Mfr's aiming for stricter limits = more mayo).

Gave the coolant system a going over today.

Found the following inside the old header tank and thermostat housing. Not sure if this is general coolant system sludge/scum or the more deadly oil from HG.

If you are concerned about the head gasket, you could get a compression check done of the cylinders themselves, but also get a compression check done on the coolant system (not sure exactly how this works but I presume as a sealed system one can pressurise the coolant system and then see whether this pressure is retained). I wonder if checking the spark plug appearance would be indicative of head gasket problems. I'd also be inclined to drain the coolant system and put the proper orange coolant in. Good luck!