Help! Coolant Leaking into Oil.

[deathkeeper]

I am in the middle of a full timing chain job on a KA24DE. I have everything removed and am about to replace the chains, tensioners, guides, and gears. The problem is that I did not find the problem I expected to find. My chain rattle has been EXTREMELY bad at startup for about a month, and then one day I got white smoke out of the exhaust. It was not a huge amount, but was sweet smelling so there was no doubt it was coolant. Popped the hood and the coolant overflow bottle was empty. I thought that the chain finally chewed a hole through the coolant channel in the front cover, so I pushed it into the garage not wanting the engine to run at all with any coolant in the oil.

So I get the lower cover off to find a fully intact chain guide, and a front cover in perfect condition with no scoring from the chain. The chain itself was loose and the lower tensioner pretty weak, so at least I did not do all of this work for nothing.

I don't want to think about the headgasket at this point, but I have found another place that I think the coolant is leaking into the oil from. Where the lower front cover seals with the engine block, is it possible that the gasket could fail around where the big coolant channel mates? A blue colored gasket was used on my engine, but it is stained rust colored around the coolant channel as if coolant has been leaking into the engine from here.

Does anyone else see this as a probable cause of my coolant leak?

I have some nice nissan OEM liquid gasket to seal all of this stuff up really good.

[AZhitman]

Could also signal a cracked block.

[deathkeeper]

I don't want to hear that. The engine only has 98,000 miles on it. After further inspection, I am fairly confident that it is the gasket.

[pmkls2]

well, from the factory I believe that they used sealer on the fron cover so if there was a gasket on there then the cover has probably been off before thus making it pretty likely that it was the cause of the leak given your description