I have a 1990 F150 that i bought a month ago. I paid $700 for it. It had been used as a yard truck for 15 yrs, but it has barely any rust. I have undercoated the frame, did the upper and lower ball joints, tightened the steering box, got new front tires, exhaust, re did the steering linkage, and changed the oil. When i got home I checked the oil. The dipstick was white and there was no oil on it. I drained the oil and only about 3 quarts came out and it was mud colored. There doesn't seem to be coolant leaking into the oil. Could it be a blown head gasket or something else? I heard that synthetic oil attracts water so could it be that? The engine also ticks almost like if you tapped on a piece if cast iron with a screwdriver for a few minutes when its warming up, but before I changed the oil and filter it didn't. I used a Purolator filter and Valvoline high mileage 10w30. The engine has over 168,000.

 

Mud for oil is certainly what you do not want to find. Yes, it could be a head gasket, but you say it does not appear to be losing coolant?

I think, change the oil and run it. Keep an eye on the dipstick and address any problems. Mud for oil could have simply been poor maintenance.

No guarantees. There could be excessive wear if the oil was not changed regularly.

 

I checked the coolant and its full. I am going to change the oil again, but with Pennzoil which I should have used. (use it in other engines i have). The old oil was sort of brown last month when i bought it. I changed it a couple days later and this I just noticed this issue. There has only been about 50 miles on my oil change.

 

could be intake gasket leak too. mud color usually indicates water in the oil. almost has to be using coolant..

 

That is lots of oil to use / lose in 50 miles. Do you have leaks or smokey exhaust?