busted radiator? or BHG?

[denny2hand]

I have an '89 N/A with 107k. The seam around the top of my radiator is cracked and leaking coolant at a really slow rate. Even after driving for 45 minutes it's a minimal leak. When I take the cap off the next morning when it's cold it releases pressure from the cap. I took it to a shop today and the guy told me it must be a BHG causing the radiator to crack. I have no overheating issues and the temp gauge needle is steady at half or below half on the gauge. The oil looks clean and there is nothing coming out of the exhaust. Is this guy blowing smoke up my rear or could it possibly be a BHG? Could a BHG create enough pressure to crack a radiator?



Dennis