rs2 cooling fan problem

[Eastcoastrs2]

When the cooling fan of my rs2 kicks in just above 90, revs drop, lights dim and there is sometimes electrical noise from under the dash.
I was checking a few things and had the engine bay open when the fan kicked in and it seemed to start stop and then start again as if it was struggling to kick in.
Any thoughts?
When I turned the car off there was bubbling noises like liquid boiling around the radiator area, this only started a minute or so after turning the engine off. It didn't sound good.
I'm not losing any coolant. The temp gauge sits at 3 bars below 90 while driving and gets to max 2 bars over 90 when idling in traffic but with the boiling noise I am worried it's getting too hot?
Maybe unrelated but I've also noticed that if I start the car and let it idle it starts blowing white smoke after about 2-3 minutes also a small amount of white smoke when giving it a little.

[UrS4boy]

Bubbling and white smoke are both indications of a blown head gasket.

Sorry.

[Eastcoastrs2]

Any other indications I should look for? or is this pretty definitive?
I'm not losing any coolant and there is no white stuff on oil cap or dipstick.
Car seems to run fine otherwise and doesn't overheat even on long drives.
I average 24 mpg, and it get's driven!
It only puffs a small amount of white smoke when I really hit the throttle.
The smoking at idle was concerning me, really bad when cars sat overnight, not so bad when only sat for an hour or so.
I ran the car up to temp and when hot there is small bubbles visible in the overflow into header tank, worse when I blip the throttle. I guess this is a bad sign.
If worst comes to worst what's the best place to buy head gasket kits?

[Monkeymagic]

If you get smoke after log periods of idle it would indicate valve stem seals/guides are worn. As for bubbles in header tank the definitive test is to conduct a sniffer test. The only real reason you would get bubbles is combustion gas from a cylinder entering the coolant system. If this continues it will eventually over pressurise the system preventing it from circulating. If the sniffer test indicates combustion gas then pull the head and have it worked before fitting new head gasket.

[Eastcoastrs2]

Had a mechanic do a test today to see if there was combustion gas in the coolant.
It came back all good, no gas present so I don't know whats going on.
Any other ideas?

[John.]

If the fan is kicking in late then maybe the coolant is boiling and causing air pockets which may be why you're hearing the bubbling noises? If system isn't holding sufficient pressure then boiling temp will drop.........why not replace the expansion tank cap and see if any different?
After-run pump working?