Last week, me and the GF were driving back from her Dad's in her Stilo, it drove fine, I didn't notice anything out of the ordinary, I didnt notice any high temperatures or anything, not that I was particulary looking. We parked up outside my sisters for about 20mins then got back in the car to go home. When i started the car it sounded horrible, like it was running on 3 cylinders. I got out the car went round to the rear and there was alot of white smoke and you could clearly hear through the exaust that it was running horribly. I gave it a quick couple of revs and it went back to normal and there was dramatically less white smoke, so I figured at the time it was possibly a dodgy plug or coil pack so we drove it home and parked it up. The next morning I started it and it ran okay, but there was alot white smoke again and it wasn't going away, so i hooked up a diagnostic machine and found no error codes. At this point it occured to me it might be the HG. I checked the header tank and it was way below the minimum mark, i dont check it that often as its her car, but everytime i have its been up near the full mark. I've checked the engine oil at the dip stick and it was fine, no signs of milkiness.
What i'm thinking is the HG is maybe leaking into the combustion side, which would be why it sounded like it was running on 3 cylinders when i started it at my sisters?
My Q's are:
Is there any way I can say for 100% that it is a HG leak before i tackle it, maybe get the coolant tested for CO2 or something like that?
Secondly, because of the cost of labor I am toying with the idea of tackling this myself, her Grandad used to be a mechanic so can help me out with the more techincal side of things and I would do all the physical labour. Are there any special tools I would need to do the job, maybe Fiat specific ones? Also, is it best practice to just get the head skimmed regardless? Lastly, is there anything I should particulary look out for when removing/putting it all back together. I've got a friend who works at an autofactors that can get me all the bits at cost price as a favour which is also making me think I should have a go at it myself. The car in Q is a 54 plate Fiat Silo 1.6 petrol.
Any input would greatly be appreciated.
Thanks
Daniel/Tasha