My son is in high school automotive shop.He recently put head gaskets on his 1992 sierra with a 4.3L v-6.It was getting antifreeze in drivers side back cylinder before he changed gaskets.Had heads all redone by machine shop (best in our area) and put all back together but now is not holding pressure in coolant system and is getting antifreeze in passenger side back 2 cylinders.Could he have installed intake gaskets wrong or any other ideas. Thanks for any replies.

My son is in high school automotive shop.He recently put head gaskets on his 1992 sierra with a 4.3L v-6.It was getting antifreeze in drivers side back cylinder before he changed gaskets.Had heads all redone by machine shop (best in our area) and put all back together but now is not holding pressure in coolant system and is getting antifreeze in passenger side back 2 cylinders.Could he have installed intake gaskets wrong or any other ideas. Thanks for any replies.

Unfortunately, the only way to find out what went wrong is to pull the intake and inspect the gaskets.

I usually use a little Gasgacinch (made by Edelbrock) on the intake manifold gaskets to help hold them in place so they don't move while the intake is being installed.

//2000CAYukon