When did the 4.0 change from V-belt drive to serpentine?

 

Did you do the test I described in post #32? Adding pressure in the system raises the boiling point, so if you do the test and can decrease the thumping by adding pressure then you know the trouble is a hot spot.

The thumping is most likely the result of a steam pocket forming in the cylinder head. Around the exhaust valve seats are the hottest point.

Since the 4.0 has two TSBs that mention this problem, I'm thinking that there is a design flaw and anything that is not right in the system is going to make the problem appear.

 

Bruce - wouldn't you be able to tell if the pump was turning backwards by looking at the external housing? In order to reverse the rotation of the pump they'd have to not only change the impeller, they have to redo the housing so that the exit was "reversed"as well, wouldn't they? The radiator hose outlet has to follow the rotation of the impeller?

 

No only the pulley and the impeller are different. This is not true in all cases. The outlets of the pump have to be into the heads and block. The inlet has to be from the radiator. The angle of the inlet may/should change. The v belt drives from the inside, but in many cases the serpentine belt drives from the outside of the belt, thus reversing the direction of rotation. Doesn't have to be, but it can be. The impeller design is different so it would become very inefficient. I don't know those motors so I have to ask. Next question is, whoever has the serpentine setup, does the belt drive the water pump from the inside of the belt or the outside??? If it does drive from the inside of the belt, then that line of thought is out.

But to have a hot spot and that incidence of the collapsed upper hose, it is a question. The upper hose collapse could be caused by the pressure cap not allowing air in when the system cools.

 

I did do the test and the rsult was the same no change but i just cam back from the ford dealer and found that my waterpump is defective and thats whats causing the problem! The water is new but i bought it from advance auto parts and was told from the mechanic that it was creating an uneven flo! The result is i have bought a new oem waterpump that im going to install myself on the next nice day... 257.00 for the waterpump omg! But i was told thats what it was and they were super nice to me and only charged me 25.00 to diag it.

 

I called today & they told me the samething $256.00 . I had thought it was this for a while now but wasnt sure . I was checking mine today & well i dont really get a flow at all thru the radiator . The radiator is fine as i have flushed it 2 or 3 times . I really hate to buy a high dollar water pump but i guess ill have to do the same . I cant order mine till monday so if you get yours done monday please let me know if this fixed your problem.

 

mine will be done tomorrow im sure... The mechanic told me i wasnt getting a very good flow from the waterpump i have im hoping this is it and thanks for the help Bdox about the pressure test im just glad it wasn't a hot spot.

 

That does not mean there was no hot spot. The thumping is coolant vaporizing, just like a percolator. The poor circulation is the reason that the hot spot developed.

 

does anyone have a pic of this coolant bypass kit F8PZ-8522-CA Im just wondering if i should get both the water pump & the bypass kit or just the bypass kit

 

I dont think the bypass kit is available anymore. the tsb for the bypass kit is obsolete. I fixed it without the waterpump just a lil info>>> I first checked the heater core for blockage it was good the took out the thermostat. Drilled a hole where the little hole was so i just made it bigger! Put that back in and drobe it for about 2 days. It still thimped but the 2nd day it stopped suddenly. I opened the raidiator after it cooled and the level went dor a quart. I added 50/50 mix and it has been stable for a while now so its fixed a air bubble or vapor locked idk but it burped hahaha

 

Good to know since its gonna be nice here tomorrow imm gonna try that just to see what happens . Just funny it all started after i replaced the head . Hell 2 yrs ago i put head gaskets on it cause it was seaping from head & block ON THE PASSENGERS SIDE <-- oops sry for caps . I didnt have a bit of trouble getting it burped then . It just burns me up to have something wrong with my trk &n i cant figure it out on my own . May try & make my own bypass kit . thanx for getting back to me on that fix .

 

hey no problem everyone here has been excellent in trying to help us and for people like me that is limited with cash it the only alternative. Im just hoping its a permanent fix what i did so far so good... Good luck my friend and btw since i did that fix it runs a lil cooler idk if thats the norm but it was always riding on the f mark now its a lil lower but i think thats good

 

I have an update to what has happened. !!!!!! The thumping came back!!! only 2 weekes later. So i went ahead and bout the OEM water pump. It stopped and went away after i installed it for a week. It came back and not as bad either... It thumps lightly and goes away after it idles for a couple minutes. I had a friend who is a mechanic for over twenty years take a listen and he told me he thinks its a radiator problem and its restricting the flow. Kinda makes sense to me since i let it idle for a while and the thimping goes away but when i run it normal usuage and then idle it , It thumps.. I wanted to know everybodies opinion. I wanted to buy a radiator and replace it but i will wait and see what u think. Also do i need a radiator or can i flush it with something to make it flow better? ?????

 

Ive yet to solve my problem too but i havent really been able to do much with all the cold temps & snow we have gotten over the weeks . I think its a good possibility that could be the problem , i would take the radiator off & take it too a radiator shop & have it rotted out . And reinstall it . Mine only thumps if i turn on the heat & if i turn the heat off & let it idle it will quit thumping after a min or two . If i can get a few good days & not so damn cold im gonna flush mine out & put my new water pump on . I didnt go for the $256 pump i just bought one at advance . I got a friend that works at the ford place & he said its not that much difference in the pumps to worry about . He said thats a revised pump & all the part stores have to sell the revised version too . Motorcraft just thinks their shat is gold .

 

Yea im hoping its the radiator cuz after the radiator i have to think its a hotspot maybe a head gasket. either way im gonna fix this but i hate not knowing what it is.