OK, My 83 F-150, 4.9, 4 spd has been running pretty well but, I now have a problem.

I changed the oil in Oct. and began driving a bit more than I had been since it's hunting season (I hunt birds). Anyway I checked the oil a couple of weeks later and all looked good. I went on 2 or 3 hunting trips after that before I checked it again. For duck hunting here in the desert you drive to a stock tank (like a pond), jump any ducks off it, and then drive to another tank etc. The route my partner and I take covers about 150 miles. So sometime after that oil change I began getting coolant in the oil but it could have anywhere from 200 to 500 miles of running with enough coolant going in to make oil spew out the top around the oil fill, and maybe some other places too. I discovered this in Dec and have had it parked since. I plan to send some oil off to Blackstone for analysis to see how much metal and coolant is in it.

Here are my options as I see them:

1. Put a new head gasket on and run it. That assumes that it is just a head gasket, and not the block, which I don't know for sure yet.

2. Install a reman engine. I've never done an engine swap before but I think I can do it. I would need to get a cherry picker since I don't have one. I think I'd need to get one for option 1 too, since I don't think I can manhandle a 90 lb cylinder head out of the engine bay without breaking something or part of me .

3. Rebuild it myself. How much does this save over buying a reman? I can get a reman for about $1400, less core deposit. The main problem with rebuilding it myself is that without a truck, I can't get the block and head to a machine shop for whatever work they'd need to do. I live way out in the boonies too.

Right now I'm leaning towards option 2, once I have enough funds to do it. Options 2 & 3 would also take care of the leaking rear and front oil seals. I figure it would also make sense to replace the clutch at the same time, so I'd have that expense too.

I'm sure I've left out some vital details here , but I'm looking for opinions. It will be a few months before I can afford to replace or rebuild, so I've got plenty of time to think about it.

Thanks.

 

Call me lazy, but I wouldn't spend a dime until pressure testing the cooling system. Maybe you'll get lucky and discover something simple like a failed gasket between the timing cover and engine block. That would let coolant into the crankcase.

A leak between the intake manifold and cylinder heads would do the same thing, too.

Edit: Oops, was thinking V8. I'm not very familiar with the straight 6 and any potential leak points from the cooling system into the crankcase.

 

I agree with Karl, do some diagnosis before you start looking at major costs like that.

I'd do the leak-down-type of test.

 

Unless you have run it for a real long time, with a significant proportion of the oil being coolant, I'd imagine you're still OK.

 

Are you sure it is for a fact coolant and not that emulsified scum that can form under the valve cover during the colder months?

Additionally how is your crankcase vent and vacuum pcv etc

 

Thanks guys. I've ordered a leak down tester.

I should have also mentioned that I was getting enough blow-by that oil was collecting in the air cleaner housing. A bottle of Rislone stopped that. Also, the dipstick now shows above the fill range.

The PCV has strong suction by the thumb test.

 

Please see my edit to post #2. I was thinking of the wrong engine, but the general principles are the same.

How much coolant do you think escaped into the crankcase?

With a crack, the volume is usually very slight. Many cracks go undiscovered until rebuild time. If you're getting a large volume, I'd lean more towards a gasket problem. That would typically let a larger volume of coolant escape.

 

I don't know for sure Karl. The level in the radiator is about 1 1/2 to 2 inches below the filler neck now. It was pretty close to even with the neck last time I looked at it. The leak down test should show me if it's the gasket, right?

 

A couple of inches below the radiator neck is the normal fill level. The difference you noticed could be just from thermal expansion.

A cooling system pressure tester will tell you if the system is intact. Unfortunately, if the cooling system won't hold pressure, it doesn't tell you the location of the leak. An external leak can be easy enough to spot visually, but not so with an internal leak. Unless somebody knows some good tricks, you'll have to make some educated guesses with an internal leak.

That's why I was asking about the volume of coolant loss. I'm thinking a rapid loss would point towards a gasket, because that would create a bigger gap. On the other hand, a crack would not let much coolant through, so that is less likely if you've had a major volume loss.

The coolant level dropping a couple of inches is not serious at all, so I'm a bit puzzled. Are you positive you've got coolant in the oil? The oil level increased really high, right? I think you mentioned oil spewing from a certain point, but is the liquid level really that high? If a moderate level above normal, the crankshaft can froth up the oil and cause foaming, giving a misleading volume indication.

 

An increase in oil level... drain the pan and see what's in there, and in what proportion.

Oil floats on water.

 

Option 5 Install a good used engine. Here are some places that have 300 sixes if your air pipes are in the manifold

1984
Engine Assembly
Ford Bronco SHORT BLOCK NO HEAD,STOCK NO. 002534025 45,446 A 002534025 $250 Franks Auto & Truck Salvage, LLC USA-AZ(Apache-Junction) E-mail 480-983-3135 / 800-863-3135
1986
Engine Assembly
Ford Bronco A1 $750 A-1 Truck & Van USA-AZ(Apache-Junction) E-mail 480-983-0511
1984
Engine Assembly
Ford Truck F250 J6L132 $350 M and R Auto USA-AZ(Hereford) Request_Quote 1-800-362-0810 Request_Insurance_Quote


Here's one with the AIR in the head.

1982
Engine Assembly
Ford E150 Van nice 127,000 00016271 $500 Complete Auto Recyclers USA-AZ(Phoenix) Request_Quote 602-269-3236 / 877-874-5889 Request_Insurance_Quote

 

That's a good option for the list Dave, I had forgot about that possibility. Thanks for the searches

If it isn't raining all day tomorrow I should be able to drain it and see what comes out. It's been sitting long enough that any water should be completely separated, at least in the pan.

My leak down tester should arrive next week.

 

I wouldn't worry about the oil blowing back into the air cleaner. My 351W does that and yet keeps going strong. I tell myself it's a factory system carefully calibrated to prevent rust inside the air cleaner housing.

Was your original diagnosis of engine trouble based just on the observation of the coolant level dropping a couple of inches, coupled with the oil level rising a small amount?

As mentioned previously, that change in the coolant level is not major at all. If you were getting coolant in the oil, you should have seen a tannish/brown scumlike emulsion on the dipstick and under the oil fill cap. Did you have that? If not, coolant is probably not leaking into the oil.

I don't mean this is any spirit of second guessing you, but do want to make sure your diagnosis is correct before you open your wallet. I'm not sure if emulsified oil will separate much after sitting. You'll know for sure after draining whether there was any coolant in it. You'll either see a brown milkshake or oil sitting on a layer of coolant.

As far as the rising oil level, could that be a variation based on when you checked? Right after shutdown, not all of the oil will have drained back down to the crankcase.

Another thing to check with the oil is a fuel smell. A fuel pump diaphragm can leak into the pump housing and reach the crankcase. Most pumps have a seal to prevent this, but it could have failed a long time ago and you'd never know until fuel leaked past the diaphragm. There is also a weep hole so any fuel leak gets dumped overboard, but these commonly plug up due to all the grime around the engine. So while it's rare for fuel to leak into the crankcase, it can still happen. It's easy enough to check with a sniff test. Also feel the viscosity between your finger and thumb. Oil diluted by fuel will feel much less slippery.

 

Thanks Karl. My initial diagnosis was based on oily brown slime being all over the valve cover, where it had not been before .

I guess it could be fuel, my nose does not work nearly as well as it used to and I'd probably have to get quite close to it to detect the smell. I'll give it a good sniff when I drain it.

You might be on to something here. A couple more symptoms which I thought were unrelated problems, but may not be, are the fuel bowl and/or line apparently evaporating or draining back, even when it's not hot out. Also quite a bit of the oil/whatever mix was being carried up into the air cleaner housing. I also noticed that my idle speed was getting higher and I figured I had another vacuum leak to track down. But if fuel vapor was being carried into the air cleaner with the oil that would raise the idle too.

 

Fingers crossed that you're only looking at something external that can be easily fixed. Keep us posted on what you find when draining the oil and running the cooling system pressure test.

For the heavy blow-by and the film collecting in the valve cover, I'd gamble a couple of your hard-earned dollars on a new PCV valve. They are calibrated to open and close at certain vacuum levels. If actuating at the wrong time, that could certainly affect the idle speed and crankcase venting in one fell swoop.

If it turns out all you need is a new PCV valve and fuel pump, what do you say we split the savings? I prefer small unmarked bills with random serial numbers. Thanks.