Hissing sound from engine

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360mopar

360mopar

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I have a 1971 Dart with the 360 motor. When I turn off the car, I hear a hissing sound from the top front of the engine. It only last for a few seconds. It starts out loud and gradually stops. The hoses are all tight, I do not see any coolant leaks.
 
pretty odd - have you tried standing there and watching/listening for it? no idea what it can be - left side? right side? we need a clue.. or two..
 
Maybe there is a snake under the hood...I'd take a look. But seriously,is your coolant full? It could be the liquid running back down the hose past the t stat. A hissing Mopar is new to me...maybe it wants to be a cobra. But thats a Ford thang
 
I found the hissing. It is coming from the oil dip stick. I pull it out while it is hissing and it stops. Any thoughts on this.
 
When the hissing stops, do you still have pressure in the coolant system. You don't need to remove the cap and burn yourself, just feel the top hose. If no pressure, then it is likely from coolant. It can leak at the intake manifold cross-over and flow onto the hot head, making a steam hiss.
 
I had a similar mystery hissing coming from one of the outer exhaust manifold studs where just enough coolant (hardly any) would pass by the threads as steam.
 
I removed the pvc and the hissing is gone when I shut off the engine.
Thanks for the help
 
So make sure you check the PCV.....it could be plugged or installed backwards, or the hose to the carb is collapsed or plugged, or the passage under the carb to which the PCV hose connects is plugged with old oil crud. The PCV should be open when you stop the engine so something is plugging that up; you will have excess oil sludging and possibly water condensation in the crankcase and under the valve covers if the PCV system does not work right.
 
Check the breather/vent, where air enters the engine.. If it's plugged,, it'll suck in air from where it can,, ie dipstick

cheers
 
Yeah that's it. Just throw the PCV valve in the ditch. What in the hell was Chrysler thinkin when they put THAT on there?
 
RustyRatRod said:
... What in the hell was Chrysler thinkin when they put THAT on there?
Click to expand...
Thinking they should obey the law, like every other manufacturer since ~1960. There is little down-side to sending the blow-by gases back thru the cylinders to burn, rather than just shunting them overboard like 1950's engines did. If the rings are good, there will be minimal blow-by anyway.

It isn't anything like EGR. Interestingly, my 1996 2.4L minivan doesn't have EGR, just block-off plates. I think they put EGR on the same engine in cars (Neon, PT Cruiser), but minivans are "trucks" so can pollute more, which is a very stupid rule you might talk to your congressman about.
 
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