allenis2002

1997 Ford F-150 XLT 4.6L V8. Automatic Transmission. 2WD

I would really appreciate some help with this.
Trouble: Intermittent Loses oil- Either loses at least 3 quarts in less than 3 miles, or it loses none at all. ?
When it loses oil, the heater stops working(heater seems weak always), the engine runs fine until of course it starts to overheat. I have noticed no smoke, black or white. The coolant was recently replaced and is now a brownish/reddish color. Not milky or rainbowish like oil on top. No leaks in engine seals. No oil spots when sitting.
History: I got this truck which belonged to my wife's father who passed away recently.
Immediately fixes: replaced water pump, tires, brakes, swing arm bushings. Replace coolant resevior cap (intermitted shoots out coolant like overfull or overheated but it is neither) Still looking into that when the transmission wouldn't shift into drive . Had the transmission rebuilt and drove it home 30 miles. The day after that made it a couple miles down the road and the oil light came on, and it started overheating. No misfiring or stalling. I filled it back up with oil (4qts) and drove it home. Looked it over, no Issues. The next day drove it 30 miles to the mechanic, oil loss=0. He crawled under it with me and found no leaks. Drove it another 3 days over 100 miles no issue, oil loss = 0. I checked before and after each drive. The next morning drove 3 miles and ladies and gentlemen Oil-vis has left the building!! Oil light comes on, heater starts blowing cold air, and the it starts overheating. I pull over and put in 2 quarts of oil. It is not showing on the dipstick but I limped it home and the light did not come back on. Any ideas please help. The mechanics I have talked to so far give me, "well I can TRY repalcing the head gasket." You try a $20 thermostat, not a $1500.00 head gasket replacement. I can't let this truck die. On a side note both times it has lost oil I was giving the same person a ride to work. They have been in the vehicle 2 times and the truck dumped the oil out both times. Just sayin'.

bubbabud

Oil can only go 3 places 1 out on the ground 2 out the tail pipe 3 somebody is stealing it [not likely] so you have to figure out which of the first two it is and go from there. Bubbabud

Tote-M-Pole

Ya know, Bubba is correct. If no smoke out tailpipe and no oil on ground. You are missing something elemental here. With the oil loss you are describing you have the most efficient mosquito repelent on the planet or with the oil loss you are describing your vehicle will never rust out. That oil is going somewhere. Look from the air induction to the tailpipe. Look from the radiator back. There has to be some evidence of residual oil.

I will offer something unusuial as a cause. Your passenger is a OIL sucking alien and I would not pick him up without a .357 in my hand.

JackDW

Another place that was not discussed. Oil getting into the coolant. Issues with your heater and missing oil may be related. Where did you check you coolant? In the radiator or the recovery tank. When the truck is cool check the coolant in the radiator. I think you will find your missing oil. As others have said, that much oil is going somewhere and it should be easy to find.

papa tiger

When it's hot and not seeping past the drain plug or the filter gasket, recheck how you check the dip stick. Dry it off and dip the oil several times. You may be hastily fooling your self thinking oil is on the stick when it is just bubbles and the engine is really 2 qts low. Then look at your pcv for a malf. If it is even slightly questionable replace it. A sticky valve may really suck out the oil. Everyone following you loves your rich smell. Even heard of a water pump impeller suddenly just rusting away and disappearing. Only way to find out was to pull it. Impeller could even just spin on the shaft not circulating water, causing overheat and extreme oil usage. Is your coolant bottle full of oil. It may be milky or very dark depending on how much is in it. It should be everywhere if it is getting into the coolant from an oil passageway as the PSI is 40 +. Your head bolts may have fatiqued and stretched letting the headgasket go south, a sealing malf. I don't know your mileage but the age of the vehicle is about right for a lot of seals, gaskets, head, intake manifold, corrosion problems to begin to pop up. Trips to the auto salvage yard are about to happen probably. Corrosion really cramps em down hard. The blowing of coolant out tells me thermostat, radiator cap, or head gasket. All can be pressure tested for leak down rate. If you can't pump em up, you can't keep running the truck. It will blow. If everything us up to specs with PSI than look to clogged radiator and heater core. But the oil thing in the coolant is first if so.

joshtowal

Two things you can try.

1.Put a dye in the engine oil, let it run for a few minutes and shine a black light under the hood and at the tailpipe.
2. Tell that mechanic he's an idiot. Don't blindly replace a head gasket. You can tell very easily if the engine needs to come apart or not with a leakdown test. All you do is hook up an air compressor to the spark plug port via a leakdown tester gauge and watch for a drop in pressure (the cylinder being tested needs to be at TDC). If you see a significant drop in pressure, you need to listen for where the air is escaping. take off the oil filler cap (worn piston rings), and listen for escaping air or bubbles. same thing with the radiator cap (head gasket or cracked head/block), tailpipe (burnt exhaust valve), and air intake hose (intake valve)

Again, repeat the test until your confident that the cylinder is at top dead center (both valves are closed) and you will have your answer. If you have an air compressor, I think you can get a leakdown tester for as cheap as $60. Much cheaper than that parts slinger...ahem..."mechanic"

transmaster

4.6L V8 early on in F150 had bad timing covers. They where cast too thin and warped causing all kinds of problems with oil leaking into every thing.