Ferocity02

iTrader: (60)

Did some valve work tonight and noticed a hissing sound when turning the engine over by hand. Sounds like air leaking or something as if pressure is being released. After turning the motor lets say 20 degrees, it will hiss for 3-5 seconds. The hissing is coming from the driver side only near the rear. Passenger side was dead silent. It hisses even with all spark plugs on the driver side removed which I thought was weird. Driver side rockers on or off, it still hisses.

I probably did about 4 full crank rotations by hand and the hissing never stopped or lessened. It's like somehow pressure is building in the cylinders even though the plugs are out. The plugs were still in on the passenger side, but how could pressure over there make a noise on the rear driver's side?

I can't think of anything back here that would cause this sound. I've been trying to track down a metallic tapping sound around cylinders 5-7, same area where this sound is coming from. Perhaps they are related?

Ferocity02

iTrader: (60)

Just came up with a theory actually. The passenger side might just be sucking in air through the PCV valve, which is located as the back of the drivers side on a 5.3L. I shall investigate tomorrow.

trevmust

answered your own question lol. HIGHFIVES ALL AROUND

Ferocity02

iTrader: (60)

It's the only thing I could think of.

Ferocity02

iTrader: (60)

Figured it out... wasn't the PCV. But rather the hissing sound caused by the air leaking past the rings on bank 2 was going through the block and coming out of the head on bank 1 where I had the valve cover remove. I pulled the valve cover on bank 2 and heard the same hissing sound

chrisfrost

iTrader: (8)

That's what I was thinkin ,,,,,,,,,,,,either that or maybe a snake wiggled it's way into You're engine ?????????,,,,,,,,,,he he jus kiddin

cmd1126

iTrader: (1)

I have the same issue. Is this normal if not how do I fix it?

bbond105

normal

cmd1126

iTrader: (1)

My only difference is that my engine is a fresh rebuild and does not hiss when the plugs are pulled and hooking up the starter to a batter with jumper cables will not turn the engine over with the spark plugs in

cmd1126

iTrader: (1)

Help please!

bbond105

It will not hiss with the spark plugs removed because the compression is going out the spark plug holes. Can you turn the crankshaft with some type of wrench? If the crankshaft rotates with not a lot of effort your starter is defective, your battery is weak or not fully charged or your jumper cables are too small.

Taxman20

iTrader: (11)

Its normal for the engine to "hiss" when the plugs are in it. ALL engines do this. Its the compressed air getting past the rings. Completely normal. Move along, nothing to see here.

Nickster 7

Same happens when you turn over a small engine by hand. Have a 12HP Briggs on an old riding mower that does this.