White smoke bellowing out the exhaust

[Niche]

Headgasket? My engine did overheat once very badly where the water pump failed, the smoke comes out like every 20 minutes.

I will check tonight to see if my coolant goes down and I'm having my engine tested to see if the headgasket has blown this saturday. But I've been noticing A LOT of black deposits coming out the exhaust (a build up of dirt inside the catalic? It is a new catalic so I dont know), any help would be appreciated.

Nick.

[musto]

sounds like a headgasket mate. is it misfireing??? water in oil (goes white)

[one litre wonder ;)]

headgasket if your coolant level is constantly going down , also check under the oil cap if its white and gunky then that would confirm it

there could be other reasons but thats my initial guess

[Niche]

No white sticky substances and coolant is still level 2 weeks later, white smoke issue has gone.

I put it down to a build up of dirt in the engine being cleared out where the previous owner only done short journeys OR the new CAT Convertor.