Problems with 97 sierra 5.7l vortec

dboyzus · March 7

So I've got this 1997 GMC Sierra 1500 4wd with the 5.7l vortec in it. Was having some trouble with the fuel pump but got that taken care of with a new pump and regulator.

I'm having difficulty pinpointing a water leak on the passenger side head on the back. I first thought it was the intake gaskets, so I replaced them. The head did not appear damaged as far as I could see nor did the intake manifold. I got it all back together and started it and it was still dripping.

Went out yesterday and tried to start the truck and it was like it was almost hydro locked. What are the odds I've got a cracked head or blowed head gasket?

Also the truck idles fine for a minute then slowly starts to almost stall out, and then revs back up and slowly works its way down again. It does this up until it finally stalls and dies.

txab · March 7

Can't recall, does the heater core have a line that comes off the back of the engine on that side? Check that and heater core connections

biscaynekid · March 11

If the truck hydro-locked, it means water is getting into a cylinder as well as leaking externally. You can’t compress water.
You will see white smoke coming out the tail pipe too.

You’ve replaced the intake so the head would be most likely source.

You could try head sealer additive to buy some time.

Research to see which one folks have had good luck with.

Brian Lindsey · May 6

i agree , bad head gasket , it is not blown yet , but if not taken care of , it will get worse, those sealer products may work , but only a temp fix, my advise is do it right once