Bypass hose expanding

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82CRUISER

82CRUISER

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so while I rev up my engine I noticed the bypass hose expanding like a balloon with the rpm then returns to shape at idle. It's a AutoZone hose on a 97 magnum 360. Car is a 72 duster. Thanks for the help
 
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How'd you get a 360 into an L platform?

Also do you have a crankcase vent? Sounds like it's building pressure past the rings and causing positive crankcase pressure.

Riddler
 
My bad it's a typo. It's a 72 and yes it's the coolant hose
 
69_340_GTS said:
Pretty sure he's talking about the hose that goes from the intake manifold to the water pump. As in "coolant bypass hose".
Click to expand...

Fair enough... Maybe OP could check to see if headgasket is gone or maybe cylinder pressure is getting into the water jackets? A hose replacement has been suggested already.

Riddler
 
Other than a leak down test what else should I do? It runs great and doesn't overheat
 
I wouldn't buy a hose from auto zone, I'd get a quality one like a gates from napa perhaps, or right from your local dodge dealer
 
By chance were the intake gaskets changed before this started?
 
You need to figure that out in a hurry, cuz if that is a pressure spike,the rad is seeing it too; and she won't put up with that for long.

I guess I should ask; is the pump turning in the right direction?
 
Re: head gasket and excessive pressure, I would think radiator cap would relieve pressure before it got to that point. Also if head gasket were leaking wouldn't bubbles be appearant in The radiator and /or coolant be present in The oil?
Yote
 
Intake gaskets have not been changed and it doesn't overheat. Pump is turning in the right direction. No bubbles in the coolant and no oil or coolant in the wrong area. I was thinking of drilling a small 1/8" hole in the thermostat flange to bypass coolant. I thought maybe the pump was a high volume. Doubt that would cause that. Thought about a restricted cooling system but then I would have more problems. I am gonna do a lk down test to find something. I try to live by don't fix it unless it's broke because I normally open up a can I can't close. Yet I can't turn a blind eye to this.
 
Keep in mind, the bypass is mostly active when the engine is running at below the thermostat's rated opening point. It is simply returning the hot water back to the pump for another go-round. Eventually the stat will open, and then the hot water will head for the rad.
During the warm-up period the cooling system is just coming up to pressure. You may simply be seeing the system in action before the pressure comes up?
 
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