Hello all i have a 2001 F-150 XLT 4.6L V8. i just recently replaced the water pump Alternator and the battery all at once. and i noticed a small pool of coolant accumulating on the engine block of my truck. after completing the replace ment of the water pump alternator and battery i started my truck and saw a small pin hole like leak below the thermostat housing. any ideas on how or what i can do to fix this??

Thanks in advance.


2001 F-150 XLT 4.6L V8

 

Sounds like you have a casting pin hole that has corroded through.
You might try drilling the hole through, tapping it for thread, then use short Stainless Steel bolt with good sealer or drill and tap for a 1/8" pipe plug with sealer.
The pipe plug has tapered threads so should get tighter as you wind it in as long as the don't thread the hole to large with the Tap.
With a pipe plug, don't try killing it with excess tighening because you risk cracking the casting. The seal only has to hold pressure of about 15 to 18 psi at the very most or the limit of the pressure cap..
Another possible way is to prepare the surface dry and try a surface sealer meant to take heat of at least 250 degrees F and hang on hard.
I have used J B Weld on small engine blocks crank cases with no problem.
Otherwise it's change the manifold.
Good luck.

 

Thanks bro im thinking i might put a new manifold in but ill try the seal first. thanks again ill update on the status when i get down to it.

 

well looks like the guy i bought it from failed to mention he put a rivet were that pin hole was so when i was working on taking everything out to get to where i thought it was i found the rivet and it came out with just tapping it with a flat head screw driver. so im thinking im going to happen to replace the upper intake manifold completely. I have thought that maybe i can get my welder out and use a piece of metal to do a patch job until i get a new manifold in.

Thoughts??

 

I'd try JB Weld.

 

Normally i would but the hole the rivet made is about the size of a nickel. so might weld and J B Weld it taking on a trailer to my shop to see what i can do.

 

Okay, so today after looking over the hole and examining what my choices were. I took off air intake using my flat head 10-8, and the clamp the factory puts in. i then undid the hose from the thermostat housing and moved out of the way using channel locks to "pinch" the hose clamp. i took some house hold sand paper and sanded down the area which need the hole repaired, after that i took a 1" strip of duck tape (Yes duck tape.) and placed it over the hole. and then took J B Weld and put it over the entire piece of duck tape as well as 1/4" out side the tape. I then placed another 1" Strip of duck tape over the J B Weld and another coat of J B Weld on just the out side of the tape. I'm going to let it sit and dry over night and see if this works if not i'm welding it at the shop later this week.

 

Looks like my attempt failed i have order a new intake manifold to put in myself. anyone know what it will take to put this is when it comes in i might just take it to a shop and have someone professionally install it if it requires to much. so with that being said cost? and or do it myself?

 

Honestly I don't agree with the way you tried the fix using soft layers of tape.
The metal surface should have been roughed up well with a course file for a sealer to grip directly to the surface because the cooling system operates at close to 14 psi pressure.
Soft tape even covered with your sealer does not provide a firm surface and strength to adhere to.
I still feel JB Weld applied as mentioned will provide the seal you need.
The Red and Black JB Weld will hold at up over 500 degrees and over 3900 psi given a chance to cure like over nite or 24 hours before filling with coolant..
Good luck..

 

- That duct tape must go down and remain wrinkle free.

Yea, the do that. Right! -It is a casting flaw,- that develops into a leak. A pin hole as mentioned. A two second job with a spool gun. (welder) , - Filled , not patched. A spool gun is a aluminum wire feed MIG welder add on. Just for aluminum. Easy fix once removed.

Yea, -JB could work, - so could the Permatex metal filler used on heads.

 

I had this problem with my 98 4.6. When I bought it with 74,000 miles on it. I soon discovered I had a leak in the head below the thermostat, I then discovered it was already patched with JB Weld. I repatched with JB Weld and it lasted one year before failing. I then patched with epoxy putty which also failed after one year. So I had a yearly ritual of cleaning and patching the hole. Unfortunatly you never knew when it would fail and it it usually resulted in massive coolant loss and overheating, this over heating finally caused my head gasket to fail. One time I actually used an expanding foam earplug squeezed into the hole and by leaving the radiator cap loose so it wouldn't build pressure so I could drive it home.
Mike