So i just got my car back from a cmplete engine rebuild. Its an ls/vtec with egle rods and je pistons, honed to 81.5mm, acl ,ain and rod bearings etc. Head is a Si head, it was machined and heat treated right before it went on. boosted with a greaddy kit, but the only thing still greddy on it is the turbo and manifold, pushing 7lbs. I just finished breaking the motor in and changing the oil, the motor has about 700 miles on it. I got on it in second gear and at about 6k rpms saw some white somke from the engine bay, it has no hood on it so i saw it right away. I pull over and its smoking from directly to the right of the ehaust manifold bewtweeen the head and the block. Not a terrible amount, but its there. After it sits for a minute it goes away. The car runs and idles just fine, and i tried hitting a little boost this morning and that still acts fine. The car doesnt smoke on startup, only after warm up and it smells a bit like coolant. This is defanitly a head gasket right? I was just trying to make sure before i pulled this head off and realized it was more

 

oh, and i dont think there is much if any coolant smoke coming out of the exhaust, it was hard to tell because it was cole here this monring, but it was nothing like when i cracked my cylinder. I smelled t3he exhaust smoke and i didnt smell any coolant in it

 

its leaking coolant or oil? if it leaks coolant out of the head gasket in boost range then there will be exhaust gas in the radiator. if thats the case you could take the radiator cap off and rev the engine and it will shoot coolant up into the air.
there is also this blue fluid you can buy that turns yellow in the presence of exhaust gas, but you gotta have the special tool to use it. it the radiator hose above the head? it might be just running around

if its oil, i would be inclined to believe someone didnt clean the block very good and it just looks like its leaking because the head is so clean. look realy good at everything above it or to the side of it that could leak. ive seen rear main seals leak and travel around the oil pan so it looks like its coming out of the timing cover. dont yank the head unless you are sure

 

thanks for the info, i will try the radiator thing today. It's very weird the smoke seems top be coming from a one inch area right between the head and the block. its def not coming from the cover. But oddly enough, I drove it easy yesterday and this morning, with a small pull before i stopped, and I havent seen any smoke yet, very odd. Ill keep an eye on it though for sure. Also getting a compression test today just to make sure. The car is for sale and I dont want anything to be wrong with it