I have an 86 F250 with the 460 and C6. Daily driver, but that's only 10-15 miles per day, if that. Past week or so I've noticed the heat going in and out and could hear air/coolant gurgling in the heater core when driving, so have been keeping an eye on the coolant. I've always had to add some here and there, but this was more like adding some every other day. Now we're to the point where it's disappearing quite quickly. Can't find any leaking anywhere on the motor or on the ground below it. Engine is running fine, so I assumed I'd eventually find a leak and take care of things.

This morning I noticed no heat again. After topping off the radiator about 15 miles ago I had to add over a gallon to fill it back up. So something was definitely wrong. Started poking around a bit more and noticed a bit of oil/water mix under the oil cap, way more white "smoke" from the exhaust than I normally see on a cold morning, and now piece de resistance the oil level is rising on the dipstick and starting to turn into a delicious looking milkshake. Also, when I bought it 2 years ago the previous owner (I'm assuming) had put that copper head gasket sealer crap in the coolant.

So it's gotta be the head gaskets, right? I mean I'm sure it is, the only thing that makes me scratch my head is that there are no bubbles whatsoever coming out of the radiator and the combustion gas tester shows no combustion gas coming from the radiator. Also have 120psi on all 8 cylinders. I imagine the gasket could fail between a coolant and oil passage, leaving the combustion chamber intact and that would explain this?

Anyway, looks like I get to dig into this 460 for the first time. I've replace the head gasket on an 86 Isuzu Trooper before, so imagine it's basically the same but just doing everything twice. The main question I have is, is it 100% necessary to have the heads machined and rebuild when doing the gaskets? I don't have a garage, so have to work outside in the winter. I'd love to be able to do the whole job in a warm day or two, instead of sending taking the motor apart and then waiting a few weeks for the heads to come back. I'm also planning on putting the truck into more of a retired mode and just use it for hauling long lumber, concrete, and stuff like that, and getting a different vehicle for my daily work truck. So running good not great wouldn't be the worst thing in the world.

 

How many miles on the engine? I would at least get the heads checked by the shop to make sure they are not warped. You do not know what happened to the engine before you got it. You do know they were having problems. The may have severely overheated it and warped one or both heads. They will just lay a straight edge on them and see how bad they are. If they are bad enough, your new head gaskets are not going to seal.

If money is not a problem you probably should let them go through the heads and grind the valves check the guides and put new valve seals in it. Especially if it has a lot of miles on it.

 

43xxx on the dash, so I suspect 143xxx. I guess it could have been overheated at some point, but it has run flawlessly for the last 2 years. I mean, it still runs flawlessly except for the fact that it's mixing coolant and oil. I would think if the heads were warped it would have shown up before now. But you never know.

I would normally not think twice about having the heads resurfaced and valves taped, but it's just the time component. If I do wind up getting another truck to replace this one I guess there's no rush to get the 460 back in operation so I might as well send the heads off. There are a lot of other little things that need to be fixed on the motor, feels stupid to do the heads the right way but then leave everything else as is.

 

My take on this .......
You did not say the oil level going up was a milkshake only a sign of milkshake under the oil fill cap.
I can see this a "normal" for the amount of time the truck is driven.
You are not running it long enough, 10 to 15 miles not enough, to build up heat to boil out condensate and why it is showing under the oil cap.
The oil level may be going up from gas from a bad fuel pump if no milkshake.

Now where is the coolant going is the $98 question.
Have you felt the rug on the right side floor under the HVAC box?
Dose the inside glass fog up when it is cold and the heat on?
If yes then you have bad heater core.

Now if you cant find where the coolant is going get a coolant pressure tester, you can rent one.
Drain the oil and leave the plug out, top off the radiator and start putting pressure on the system.
If the gauge drops you got a leak somewhere. Coolant coming out the oil drain plug? Check the floor / rug again and all around the engine bay hosses and water pump.

I would find just where the coolant is going before I would pull them heavy azz heads
Dave ----

 

I thought the same thing regarding the oil cap. I've had that happen on plenty of other cars that I just drive short mileage on. Also, I was confused because I've never dealt with a bad head gasket where I didn't have either coolant leaking from the gasket and out of the engine, or a bubbling radiator. I also did the rubber glove test (all plugs removed, glove rubber banded to the radiator fill neck, look for air while also checking compression) and didn't see any air or gas coming out of the radiator. If anything it was sucking the glove into the radiator. Then the combustion gas test came back clean. The tester was barely pulling any gas into, just slight bubbles here and there. Didn't look like a fizzy soda or anything that I've on a bad one before.

However the dipstick sure is looking like a melted chocolate sundae that my daughter left out on the counter, minus the sprinkles.

 

I would drain oil and change filter and with plug out do a pressure test to see if coolant comes out and go from there.
Dave ----

 

It could also be the timing cover or the gasket where the intake manifold contacts the head. If the engine is running good then water is not entering the combustion chamber. I would go for the timing cover first.

 

Sorry, a bit confused on this. You're saying that water could be leaking into the oil at the timing cover or the intake manifold gasket? Or that it could just be leaking out and onto the ground at these places? If coolant somehow got into the oil gallery that would make sense why I'm seeing water in the oil but the combustion seems normal in all cylinders.

 

I did think of the intake gasket but did not know if it is "wet" water thru it or now and why I did not say anything.
Now the timing cover is good and never gave it a thought

K.I.R.
Ok here is the way I see it, coolant can not get into a oil gallery because of pressures. Cooling system runs maybe 18 psi when it is out to temp and a good radiator cap and the oil system will have more then that anywhere other than under the intake manifold and the oil pan.
Timing covers have been known to get holes in them and leak. If you are lucky like I was on my 02 Dodge 5.9 it leaked on the outside where I could smell it and later seen a puddle under the truck.
You maybe not so lucky and the hole could be on the inside / chain side where there is no psi but the cooling system dose and the coolant leaks into the timing chain area and down into the oil pan.
If the intake is "wet type" a bad gasket can leak coolant into the lifter valley and it drains down into the oil pan.

Again a cooling system psi test, no oil plug in pan and see if coolant comes out and if it dose then where do you look intake gaskets or timing cover?
How many miles on the motor / timing chain, dose it have play and could be replaced? If so I would pull the cover to replace the chain and gears and look the cover over good for a coolant leak into the oil side. Heck maybe just replace it too cant be too much for a new one.
Once together you can psi test and see if you still get water out the drain plug hole if so pull the intake but you know the chain needed to be replaced because of the play so nothing last there.
Dave ----

 

BTW where in NC you at?
I am 30 min east of Raleigh on I40

There is a NC chapter area down lower on the forum that you can post in as we have members all over the state and maybe someone is close and can give a 2nd set of eyes?
https://www.ford-trucks.com/forums/forum88/
Dave ----

 

I'm in Brevard, SW of Asheville. Thanks for the info I'll check it out .

Sounds like there are definitely some options other than head gaskets, which is great! I'll do some digging and will start with a pressure test.

 

Ashville is out there a bit from Raleigh

Yea there are options, if coolant dose come out the drain hole and with high mileage and maybe needing a timing chain I would look at the timing cover were the leak maybe.
Dave ----

 

So, I'm pretty sure y'all are right and it's the timing cover that's leaking into the pan. Got the water pump off and there was a ton of crap built up between it and the plate, as well as on the timing cover. Under the timing cover there's also a ton of crap built up in all of the passages. Guessing it's that copper additive that the previous owner put in the radiator?

As for the timing cover itself; there are two bolts that hold the timing indicator (not sure if this is what it's called) over the harmonic balancer. On is 1/2" and the other is tiny, When I was removing the tiny one the head snapped right off. I imagine I can get the indicator back on there and to stay with the one complete bolt and what's leftover of the tiny one, but should I just replace the whole cover while I'm at it? They're not that expensive and I don't really want to get everything back together and then have to take it apart again.

Also, the timing chain has about 2" of play in it, so that's definitely gonna have to be replaced while the cover is off. Any recommendations on a specific chain?

 

On the timing cover do you see anywhere a crack or pin hole where coolant could of made it's way to the oil side?
I am also guessing that 1 small bolt that held the timing pointer is a threaded hole so a new cover and new bolt to fit should take care of that.
Look over all the timing cover bolts and if any show pitting / rust I would replace them with new.
So being not much money for a new cover and what you see I would replace it.

As for the timing chain I am seeing a plastic cam gear so it is either factory or someone replaced it with a factory type not the best way to go in my book.
Also am I seeing some missing teeth at the 2:30 - 3 o clock place? Either way with the play you say it has should be replaced being you are there.
You are looking for a full roller type chain. I also hear that the 80's chain gear set is re-tarted for smog so you may want to go with one from maybe the late 70's?
If I am off on any of this I am sure someone will say so.
Dave ----

 

Thanks for the info. No crack as far as I can see in the timing cover, but I went ahead and ordered a replacement when I was ordering everything else. With the amount of corrosion and buildup where there should not have been coolant, I think it's certain that water was making its way into the pan from behind the timing cover. I also ordered a set of stainless bolts for the water pump/timing cover. The black oxide ones that were in there had a ton of corrosion on them. Especially the two that go into the water jacket.

I don't think there are any missing teeth on the cam gear, maybe it just looks that way in the picture. I just went and checked and the gear has a Ford logo imprinted on it as well at 1984 casting marks, so I'm assuming it's original. I think the discoloration is from the chain riding on that part of the gear. I also ordered a replacement chain. As for swapping out the chain, as long as I line up the two dots on the gears at TDC, I should just be able to pull off the gears, swap the chain, and replace, correct?