During a thumping episode, try turning the **** to MAX AC which should cut off the hot coolant flowing through the heater core, and see if thumping stops.

 

Did you mention that you have a pressure tester?

If you have one, you could put it on in place of your radiator cap. Warm the engine up to operating temperature. When the thumping starts, pump pressure in to the system, say up to twenty psi and see if it stops. This will raise the boiling temp of the system, so if the thumping stops, it would be a fair bet that you have a hot spot in one of the heads that is generating steam.

 

ok i will try that tomorrow then and let u know what i find ok? I hope i dont have a hot spot

 

Yeah, I hope not. But finding the trouble means eliminating possibilities.

 

Sorry to ask but i may have missed the answer..You did or did not have this issue before the repairs?.. you had a mech do those repairs? and after you get it back it suddenly is making all these noises?...Time for a new mech..time to get him more involved in the cure..(well thats my opinion.sorry) If you add the flush kit i would watch the run off closely..I am wondering if something got in the water system while it was appart. If you are willing and are doing all these other suggestions. why not disconnect or bypass the heater core all together and try to burp the engine alone and see if you are still having the problem(s). the smell in the cab makes me think you do have a leak in the cab.. another problem. perhaps not entirely related to the original but now being noticed. something to keep in mind. Good Luck.

 

No i had none of this going on as a problem before the work was done. I had a mechanic do it as a side job. He is a mechanic at a garage nearbye. he has a lot of years doing it but since i had this problem i havent heard from him but i think he is just busy. I called yesterday left a message he should call today i need this to be fixed. Im not sure its caused from his work or not so im not gonna jump to conclusions either since im a fair guy i will find the problem first. Got the flush kit and im gonna try in a few minutes after my coffee :-) Thanks for everyones help I really do appreciate it since i dont have a lotta money and im a single dad money is tight and I couldnt afford to take it and pay for a repair. But I am willing to work at it.

 

Ok I think i might have found the problem !!!
1. I bought another OEM thermostat and went in and replaced the other one.
2. Before that i bought the flush kit and flushed the system, Found stuff that looked like a soft material, very little and it was reddish in color. Got the system very clean.
3. Buttoned it all up with the new thrmostat and added antifreeze 50/50 mix!

Im running it now and will let u know the results but im wondering if this guy left a rag in the hole were the timing chain was for the antifreeze that would explain a lot and i would still have this problem until he went back in and got that rag right??? idk we will see? I'll check back in soon when i have it up to temp and see if it works.

 

Ok! I have burped it the best i can and still have the thumping noise. I flushed it and found some stuff not much at all and its now clean. Its just funny i never had this noise before the repair and now i do. idk.

 

Dont get me wrong. I understand why you did it the way you did. I too have kids and these darn trucks arent cheep. If I could help physically I would be all over it. I would be curious if you could cut the heater core out of the loop to try to eliminate if it is truely the culpret or just a microphone for some other suspect.

Well stuff in the system isnt good. So watch it close and consider another flush soon to see if you get anything more stuff knocked loose. With my limited budget.. I think I would start cutting(as a figure of speach) stuff out of the loop to try to narrow it down. Good luck.
TruckCentral

 

Use your pressure tester in place of the pressure cap. Pump it up to twenty psi when the thumping noise is going on and see if it changes the sound at all.

If no change, shut it down and observe the pressure over half an hour.

Let us know what you get, OK?

 

ok I will do the pressure test and see what happens! Bdox thanks a lot ... And Truck central thanks for understanding I was very frustrated the other day and i hate not understanding whats going on with my truck. Just a quick note i am very thankful for everyone helping me out here and realize there just so much u can do through the computer. I will try my best to do what u guys have for me and try hard. thanks so much... Dave

 

I have the exact same problem with my ranger Its a 98 4.0 . I just put a new head on last week & soon after it started this . I have done a combustion leak test to see if combustion gases are getting in the coolant . Test was Negative . I too can turn off the heater & all thumping stops Ive burped the system several time done everything i can think of except hang the truck from a tree with frontend straight up in the air . The temp gauge is normal & the truck runs great its just this thumping at idle is driving me damn nuts .

Installed new head
new thermostat with jiggle pin up at 12oclock
New intake gaskets
Done a combustion leak test Test negative
Not losing any coolant


Is it possible that the waterpump is about to go & causing this problem ? Im gonna try bypassing the heater core today to see if that does the trick. Any help is much appriciated & if i find a cure ill post my cure .

 

I would say yes, it's possible a bad water pump could cause similar symptoms. There is an older TSB covering the 4.0L and faulty water pumps. For some reason, though, the TSB was never updated to include the 98-'00 Rangers w/4.0L OHV:

 

this only makes sense . I have also seen a TSB for some coolant bypass kit . But ford doesnt make this part anymore & is about impossible to find . I was wondering if anyone has a picture of this bypass kit . Thanx for that TSB

 

Ok i went ahead and checked to see if the heater core had any restrictions and its fine. I also pressure tested it again it was perfect. I also did the combustion test and it was good. So im leaning towards the water pump being faulty its new but maybe just not good for the truck. Idk what to do im thinking of just putting it in the garage to have it fixed then see what it was.