I bought a 1993 Ford Ranger 3.0 5 speed truck off of my neighbor who purchased it new. It sat in his back yard for 20 years and had 70K miles on it. I ended up having to replace the radiator, all the rubber hoses, heater core, break lines etc. It runs well but I am going through a quart of oil every 500 miles. I have oil now in my coolant reservoir. No oil or coolant leaks. I did watch a youtube video stating that it could be due to the water pump bolts. I had replaced the water pump. I am at a loss as to diagnose this. Saturday, I will hydrocarbon test the cooling and run a compression test. Other then this truck sitting for years it was in good shape.

Someone mentioned that it could be head gaskets.

Any advice would be appreciated.

 

Welcome to the forum

Compression test should tell you more
Remove all 6 spark plugs first, then do the test

Also as you remove the spark plugs keep them in order and look at the tips, darker color tips means oil burning
After testing, which spark plug came from which cylinder can be handy

Cooling system runs at 14psi pressure after warm up, so you would also be losing coolant if there was a oil/coolant cross over
And coolant in the oil
In an automatic trans vehicle then the oil would be from the transmission cooler in radiator, but you have a manual trans so that can't be it