I bought a new pickup, its a 94 4x4 22re, and there is a strange hissing sound coming from between the valve cover and intake manifold. It hisses even after i turn the engine off and I can't figure out what it is, if its important, or anything else.

Then tonight my engine started to over heat. I saw the temperature gauge start to climb and killed it before it really overheated. I added almost a gallon of coolant and it ran fine after that. There also seemed to be some smoke coming from where the hissing sound was coming from.

Since I just bought the vehicle I think the old owner just let it run out of coolant, but the two could things (hissing and overheating) could still be related. So, I'm wondering if anyone can tell me what the hissing sound could be? Is it related to the lack of coolant? How do I fix it if its serious?

Heres some of what I know about the truck: 1994 pickup 4x4 22re, new engine from the dealership 60k miles ago, oil was full a week ago and still full tonight after the heat issues, it runs and drives fine, the truck itself has 260k miles, no idea how old the radiator is.

Any help is greatly appreciated!

 

sounds like you have a bad intake manifold gasket, water/coolant vapors releasing quickly thru a crack or whole in the gasket

 

could be a blown headgasket too

 

if it was the headgasket wouldn't i be losing oil too?

 

I found the hissing sound. Its coming from a hose that runs off the intake manifold toward the engine. That might be making my gas mileage bad, but its not leaking coolant.

I pulled over after having some fun in a little mud and there was coolant leaking BAD, but not from the radiator so i think its my water pump. Anything else to look for if i suspect my water pump going bad?

Also, after I drove through a nice puddle of mud my engine misfired for a while but went away. Does that sound like mud in my intake? Maybe water in the distributor?

Thanks guys

 

as far as the mis-firing goes you most likely got a little water in the air box and made the filter a little wet

or the fan could have thrown water in the distributer cap.. my bet is that water found its way to the unattatched vacuum hose

 

what do you mean unattached vacuum hose?