2004 F150 "making oil"

Seems like dilution from gas, not discolored as it would be from water. Up from 1/2 mark on dipstick to “H” after only 6 hours. First guess for possible causes seems to be low operating temp caused by thermostat issue, leaking fuel pump or injectors. Have read about excessive idle, overpropping, not running hard, carbon build up. But I bet those will cause dilution over a longer period time, not in 6 hours. Compression was perfect in all cylinders.

If anyone has seen or had this and fixed it let me know.

I had the same problem not to long ago. Mine was a thermostat issue. Even though It had been replaced a year prior. The thermostat was causing the engine to run cold making it dump more fuel. The abundant gasoline mixed with the oil and overfilled big time. Drained the oil, changed the thermostat and I was good to go.

Thanks. How could you determine the Tstat was bad and how big a deal is it to replace? Boat is at the shop but they are really backed up and I am headed to the coast Friday with the family. Gotta get this thing back going ASAP!:smiley:

The only way to tell if the thermostat is bad is to put it in a pot of water on the stove and see if it opens up after the water heats up. I had the same issue several years ago. Took it to the mechanic and he told me it was the thermostat with out even looking at it. After he fixed the problem it lasted about 3 years befor doing it again. This time I went to the part store, spent 30 bucks on the thermostat and gasket, 15 on the oil and it took about 30 mins to fix. Also saved about 200 bucks. My thermostat was on the top of the engine and very easy to get to. You can google your engine and prob be able to download your service manual. That should show you in detail were to find it. Ever since this problem, I change my thermostat every other year. Been told the saltwater is harsh on them.

Thanks. Now I am worried if that thing has not been working for a while. Interesting no alarm or indicators to know you are running cold. I’m sure running hot is worse but still not good for them. On my next one I think I am installing a temp gauge. Not expensive I bet.

if its not the tsat, the lift pump would be the next step
first thing, is a carbon treatment


Tstat was stuck open so replaced that. One of the fuel pumps failed vacuum test (I think that is what he said) not bad but could have a small leak. So we replaced both part and will run and see what happens.

Thanks guys. Gonna keep a closer eye on the tstat from here out.

Chris - you shock treat the F150’s with something or just run some heavy dose of ringfree for next fill up?

we have a tool to inject a foaming chemical into the engine intake, while the engine is running