Hi, i have recently taken on a '99 1.3 16v 323f, its got 130,000 miles on it but has been one owner from new so seemed too good to scrap.

The head gasket had gone and the owner had replaced it only to find it still white smoking, on removal the cylinder head was found to be cracked.

He went out and bought another car so i had the Mazda from him, ive fitted a second hand head and found the cause of the cracked head to be a broken water pump rotor.

So its had a new pump, new head gasket and head, however it smokes heavily from cold, white with a very slight blue tinge, then as it warms up its just blue. If you hammer it for a while the blue smoke backs off to almost nothing, leave it to cool for an hour or two, back comes the white with blue tinge smoke again.

Ive tried K seal, and leaving the bores soaking in ATF for 2/3 days, seemed to help slightly but still not great.

Anybody have any ideas please? Are these engines common for anything? Im thinking gummed rings where the coolant has been washing the bores? Or could it just need running around for a while as the carbon will have been washed from the rings?

Maybe a PCV valve?

 

White smoke would indicate water or coolant getting into the cumbustion chambers. Keep an eye on the coolant level. If you have a loss it would confirm this probability.

Blue smoke comes from burning oil. Oil may go past the rings as you described or it may go past the valve shaft seals in this second hand head. Keep track of oil consumption.

130000 miles is about the halfway point for these engines if they are taken care of. But it seems this engine may not have received enough care. The PO let the cooling system go until the head cracked.

How does the engine sound? Do you have valve clatter, knock , piston slap? Actually a compression test might be helpful here.

Things to try: With the tank half full add 4 L of lacquer thinner (NOT PAINT THINNER!) and drive it for about 100 miles at decent speed. It should help cleaning deposits everywhere. Intake valves, rings, catalytic converter and so on.
Add "Restore" to the oil. It fills in scrapes on the bores and such and will improve compression and less oil can get past the rings.
Again monitor the oil consumption and coolant loss. That will give you a better idea what to do next.