I've recently purchased a 97 Expedition with a 4.6 W-code engine. I purchased it with the knowledge that the left bank head gasket is assumed to be leaking and needs to be replaced. Now, my only experience to date has been with 4-cylinder engines, so I'm not familiar with what happens to a V8 when the head gasket goes.

In my MX-6, when the head gasket went I had exhaust gases in the coolant and coolant in the oil, resulting in a gray, soupy mess. Right at the end before I pulled the head off the coolant was being sprayed out of the radiator cap with crazy pressure, even with the cap on.

Now, with the Expedition, there is definitely a coolant leak somewhere, but possibly not the head gasket? The fellow I bought it from drove it for a considerable distance from where he bought it to where he parked it. He would drive until the temperature gauge started getting high, then he would stop and wait to cool down, top up with water, and then continue. The truck was tested at the local Ford dealer before he got it. From what I have heard, they ran the truck for 8 hours with no problems trying to find the leak. A pressure test supposedly reported that the head gasket was leaking. There is even a sticker on the fan shroud saying that the A/C system has a leak-testing dye in it.

Now, I haven't managed to get the truck started yet (need a starter), however I have checked the oil and it is black with no gray film. The coolant is as it should be: not black, not smelling of exhaust or anything.

Is there possibly a coolant line somewhere that is leaking? The truck has rear heat/air; could one of the lines going back there be leaking? I would absolutely love it if the head gaskets were fine and the leak was something (relatively) minor, but with it being a 97 and with 375k km on the odometer, the head gasket is a strong possibility...

 

Do a hydrocarbon test on the coolant.

I'd advise you to pull the spark plugs before turning the motor over in case there is coolant in the cylinders. Otherwise, you might hydrolock it.

 

I agree with glc on both of his suggestions. The question I have is how do you know you need a new starter? If it's because the engine will not turn over then glc is right, it could possibly be because you have coolant in at least one cyl and it is preventing the piston from traveling all the way to the top of its stroke ( hydrolock). A hydrocarbon test gave me the information I needed on my 97 to indicate I had a blown head gasket. One area to look for a coolant leak on this engine is the heater tube that sticks up at the right rear (passenger side) of the intake manifold. It is not uncommon for the coolant to leak from the hose connection, dripping down onto the manifold and eventually the ground. Sometimes filling number 4 sparkplug hole with coolant and creating a miss as well. Hope you find it's something other than a head gasket. Good luck

 

My 5.4 just started leaking a small amount of coolant on the right rear, where the gasket is above the starter.

No signs of water / oil contamination, and it runs great.

I found a thread where it was suggested that the bolts be retorqued.

Anyone done this with success?

What pattern of retorquing, and any suggestions / things to watch out for?

Thanks.

 

You read it wrong, that was if your leaking oil, not coolant. My head was wet back there as well, but it was from a leaky heater core line. They leak intermittently when running, then on the cool down when parked, right over the starter. Also on top of the block @ the water pump stem (bad o-rings) and fill the block cavity until it reaches like an inspection cover, back top of the block. Then routs to over the starter and puddles on the ground after shut down. Check the cavity by flashing a light down behind the alternator, top of the block to see if coolant is standing in the cavity.

 

Well, that could be good news.

The valley in the engine is free of coolant: I don't think it's an o-ring issue.

The problem is I just cannot find the leak source.

The coolant collects and drips down onto the exhaust from the lowest, rear most tip of the head, and I can see no possible source other than a gasket; the freeze plugs seem good, and the connection behind the engine where the hose goes to the metal tube which goes to the water pump seems dry also.

Frustrating.

Guess I should focus on trying to see if it's a bad heater core line; suggestions?

 

Retorqueing will sometimes work with an oil leak like jbrew mentioned but not usually with coolant. Coolant is thinner (less viscous) than oil. Another factor is that when coolant leaks it will leave deposits along the leak pathway from heat and evaporation. When you try to compress the gasket with retorqing you end up compressing those deposits and leaving space for the coolant to still flow through. They make gasket sealing products that you put into the coolant system and it is suppose to work somewhat like radiator sealer. I have never tried it and personally am not a fan of that type of fix but it probably has its followers. Who knows it might be the cats ***.Take care.

 

This is probably better off in my other thread...

https://www.f150online.com/forums/v8...ont-start.html

 

Yep, More proof how short my memory can be. Forgot that was you...

 

Now that the engine won't turn over with a bar you can follow the advice on this thread...

 

So... an update on the situation. As it turns out the engine is far from seized. The belt was crusted on the cylinders and the A/C compressor is the only seized component, causing the engine to not turn.

I started disconnecting bits from the engine today to get it ready to pull but when I took the intake manifold off I discovered this...



The top gasket is from the JY engine, the bottom is from the truck's engine. Not sure what blew up the gasket like that, but I would say that's my coolant leak... This is from the left bank of the engine, so these are the water jackets under the thermostat housing. I was told that a compression check indicated the left bank head gasket, but if it was the intake gasket that was like this, would it give the same results? If I only have to replace these gaskets and the engine is fine, yay for me...!

 

Don't get too excited, - still need a head gasket. I am surprised the drivers side head gasket went before the right bank did.

 

Make that TWO head gaskets. I wouldn't even think of replacing just one while you have it down. FYI A compression test will not detect a burned/blown intake gasket. Looks like it got steamed pretty good. If it got that hot there may be other concerns with this engine as well. Good luck.

 

Well nuts. I never planned on stripping the engine in the truck anyways. I guess the JY engine does in after all!

 

Have you checked compresion in that one lol ? Wouldn't that suck if .......