A New One To Me

[97grsport]

Ive got the 4.0 EFI in a 97' sport and at idle it is making the strangest sound I have ever heard. Even stumped two techs. When engine is warm and at idle it makes a thud like pounding your fist on a table for example sounds like its coming from the thermostat housing and radiator hose going to the housing.If you squeeze the hose you can feel it pulse almost like a heart beat.Heres the kicker iif you shut the truck off it continues to pulse and make the noise for 3-5 minutes.I removed the hose and flushed coolant system and checked thermostat ,nothing. Any of you guy had or heard of anything remotely close to this . any thing would help.

 

[Glacier991]

When you drained and refilled the system did you purge the air? It sounds like classic old water radiator "water hammer" only in a car ! I'm betting you have air trapped in the system. Follow the procedures for properly refilling the system to remove air.

 

[dogfriend]

Also, check out these threads:

http://www.explorerforum.com/forums/showthread.php?t=63927&highlight=water+pump

Dead Link Removed

I agree that "burping" the system should solve it, but a couple of people reported the water pump could be the issue.

 

[falls guy]

Can't see it being the water pump if it does it with the engine off. When the engine is off there is nothing moving in the engine, therefore it must be water/air. Good luck!
Peace

 

[Lloyd10977]

An old mechanic's trick might help. They would drill a tiny hole (1/16 inch or less) through the face of the thermostat, thereby preventing the thermostat from trapping air. Indeed some thermostats were and are even made with a small bleed hole. Driving the car would eventually work any air into the radiator and the small hole does not effect the overall operation of the thermostat.

 

[97grsport]

Thanks guys tried the burping method worked like a charm you guys saved me some cash much luv

 

[97grsport]

To my dismay the infamous noise is back.I'm stumped.I tried the burping method and solved the problem short term,bought a thermostat with a bleed hole in it,nothing.I'm having a hard time believing that it is the water pump because when the X is turned off it continues for 2-3 minutes.let it run with the radiator cap off until it cycled thru ther was some air that came out but not much.Hose have been replaced other than that I dont know what to do

 

[dogfriend]

Maybe you should try the trick that Lloyd suggested: Drill a small hole in the face of the thermostat. If it doesn't work, the worst that could happen is that you would need another thermostat. My Ranger (2.9L) had a hole like he described in the original thermostat. Also, it was mentioned in Dead Link Removed as a possible solution to this problem.

 

[Runnin'OnEmpty]

GrSport, don't want to offend anyone with this question, but are you sure the thermostat is installed correctly? The 'pill' should point toward the block, and the 'pointed' end should point toward the radiator hose. If it's reversed, this would explain your symptoms.....

I always drill a 1/8" hole in my thermostats, even though they may already have an air bleed.

ROE

 

[351wExplorer]

have you put any new hoses on recently, and if so where they stock replacement or some you found that fit, if the hose is the highest point in the system air can be trapped up there and allow air into the system even when you think you have it bled...

just my .02

 

[97grsport]

I put the stat in properly (no offense taken) replaced hoses with stock hoses bought from don hinds ford, I'll go ahead and drill the hole in the new stat give that a whirl. should I drill the hole where the air bleed is or leave it alone and make a new hole.
Thanks guys
Brandon

 

[dogfriend]

In the other thread, Ross-n-Chicago said that he removed the little "check valve" from the hole to enlarge the hole. I would just enlarge the hole. I think the hole is supposed to be oriented in the upward position (rotated as high as possible).

 

[351wExplorer]

your right dogfriend, rotate it straight up