97 F150 4.6 windsor with 162K miles
I finally found my antifreeze leak after two weeks of smelling it and searching all over. I put in some UV dye and found puddles of antifreeze sitting in the valley area under the intake and a small trace amount around the flywheel cover on the tranny.
A little background info might be helpful. Fan clutch was a little bad so about a 1 1/2 months ago I replaced a few parts. As preventive maintenace and since they had never been changed I did a new water pump, hoses, belts, and t-stat. All went pretty well with the change execpt the pump stuck in the block cavity just a little. I did have to use a board and a small hammer to knock it loose but it wasn't a major ordeal. After the change I did get a noise similar to a fan blade hitting metal. I rechecked the fan clutch and water pump pulley bolts and the noise stopped. I'm hoping I didn't bend something and that noise I heard was the pump impeller hitting the block and caused a hole. The old pump didn't even have a mark in it so I can't see where the cast block would be bent. I hope it's just the tube or o-ring under the intake or a intake gasket. What do the experts out there think? What kinda of cost and labor is to be expected in pulling the intake to check things out?

Sorry for the ranting, this is the first real major engine problem I have had. Pretty good I guess for the mileage. Been debating on trading might be the time to do it.

 

I would think the trace amount on the fly wheel cover might be from above. I would look hard at the t-stat housing agian. Did you get it really clean and use sealant on the gasket? even the smallest bit of old gasket left behind will cause a leak. I normally use a air powered sander with a 3M pad on it to clean the intake and a bench grinder with a wire wheel to clean the housing. Same for the water pump surfaces. Obviously you don't need to clean the new pump but the block surface needs to be really clean

 

Once when I had to remove the thermostat housing/radiator hose, fluid went along the driver side head and into the valley. Maybe you could dry up as much fluid as possible, let the truck warm up so that the thermostat opens and the antifreeze begins to run through it, and watch and see if you see a leak around the thermostat housing or water pump.

 

I'm guessing that the T-stat O-ring is the culprit. When I did mine I cleaned it all up real good and the O-ring was difficult to seat when it was dry & clean.

I removed the whole works again and lubed the O-ring with straight antifreeze and also the hole that the t-stat and housing goes into and with it being slippery I was able to work the whole housing in by hand and the slowly tighten the bolts. This made a positve seal in my situation.

An O-ring is cheap and replacement is fairly easy. It's a good place to start.

Good luck.

 

Check the heater return hose on the firewall. it should be the one to the right when you are standing facing the truck and looking at the firewall. Follow it to the clamp and make sure the clamp is tight. If it is one of those squeeze clamps it could be leaking and allowing the coolant to run down the pipe and leak on to the tranny and into the valley.

Regards

Jean Marc Chartier

 

Thanks for all the suggestions guys, I will have to try a few of them out. I hope to god it's something simple, I priced the intake removal priced today and it's a 4.5 hour job and will could cost upto 250 in labor. If I only had my own garage I would do it.

All the heater hoses seem OK, I know the heater hoses above the #4 plug that everyone claims to leak have a screw type clamp added on by the previous owner.
There's no gasket on the t-stat so there's that problem gone. I think the rubber o-ring seated fine on the new t-stat and the UV dye showed no leaks coming from the t-stat. Still there is a chance it could be from here as it's hard to see the back side of the t-stat housing on the driver side.
I see no leaks from the front side of the pump and I did clean the water pump cavity out with solvent, wire brush, and very fine sandpaper. It seems as if it's coming from the backside of the pump which is in the area of that tube. It could also be coming from a side of the intake and be hidden by all the crap on the motor. It's hard to see more than just a small amount of the valley with the lower intake and the intake runner control in the way.
My local mechanic is not sure where it's from, he's a good mechanic just hasn't worked on many 4.6's. Would it be worth the $100 or less to let a Ford mechanic at least check it out, give me an idea of problem then have the work done elsewhere or do it myself?

 

Did you know that there is a small hose right behind the water pump?? It connects to a metal line that runs back under the intake. It about 3 inches long. I think its 3/8 I.D. in size. that could be where the leak is. You may want to check there.
Lariat#1

 

LARIAT1
Actually that's what I'm hoping where the leak is. According to the Haynes manual through only the Romeo engine has the short rubber line under the intake, the windsor model has a metal tube all the way to the back of the pump with an o-ring seal. I can't see or feel back there. Does the intake have to be removed to read this? Maybe the ALT, can come off and I can at least check it.

Thanks

 

I would check that heater hose by the firewall, that was the culprit on my old girl. 98 4.6L with 230000 km's

 

LE PEW, iron horse, and Pestco1
I have to give you three credit.... at least partial credit. I did find that the hose clamp on the t-stat had worked loose a little and I guess under pressure it was seeping from the hose connection at the t-stat housing and running into the valley. Now I'm not for sure if all leaks are stopped as I am still smelling it but it could just be burning off residue. I'm keeping a close I on it and double clamping all hose connections. Will probrably pull the t-stat and install a new t-stat and o-ring to be safe when the snow stops and it's above 32*. Thanks a million to everyone.

 

That's good news. I'm glad it was an easy fix (not expensive) for you.