Thu,thud,thud when you turn the engine off

[corey6969]

Has anyone heard thud thud thud thud when you turn your engine off. Its coming from the cooling system. If you put your hand on the top hose you can feel it as it thuds, kinda like its overheating but it isnt. I hooked up a cooling pressure tester and it holds pressure when you pump it up. I start it up and let it warm up and it slowly builds pressure, so that tells me theres no bad head gasket or cracked head right? When it got up to 17 psi after the thermostat opened i shut it off because i wasnt sure i let all the pressure out and started it up again and a little while later the surging started.

You can watch the top hose pulsate. Does anyone know what causes this? Im stumped and about to take er to a shop to get er diagnosed.

 

[dyeager535]

Pull the thermostat.

Coupled with your flat upper radiator hose, I'd be inclined to believe that your thermostat isn't working correctly. Is it upside down? (no idea what that would result in, but...)

 

[ragedracer]

You have air in the system. It needs to be bled out.

 

[broncoman6524]

You have air in the system. It needs to be bled out.

Agreed. You truck is sitting level when you're doing this? If not move it, the radiator cap needs to be the highest point in the entire system.

 

[Jason4x4]

try a new cap too

 

[corey6969]

Apparently thats what it was, when I refilled the coolant and started it up the coolant (after the tstat opened) was goin up as high as the bottom of the cap and as low as the heater hose port. Then after a bit the hoses started shaking real bad. So i said @*&$ it and filled er up and held it at about 4500 for about 30 seconds, did that twice, and low and behold now you can just feel a surge slightly when you grab the top hose. Thanks guys, now its time to dip into the food budget for gas $$ again

 

[ragedracer]

Since I was first with the correct answer, you can send half your gas money to me.

Right? =)

 

[corey6969]

how about a nice friendly pat on the back