alot. You should get up on top of engine and look down in the back of it with a good flashlight in the dark to see what's up...and/or underneath it so as to look from the bottom-up too...

 

Normal condensation is different than seeing milkyness from antifreeze in your oil.

 

Alot like.... more than $1000?

 

Most people at oil change places are barely qualified to change oil,so disregard what they have said. You say you have an uncle at a GM dealership,, have them guide you. They can do a better job than we can guessing.

 

It may have had the rad crack for a long time.
At some point it may have overheated due to the crack and lack of coolant.
So the Mom and Pop just filled her up and kept it full while for sale and just failed to disclose that.

Clean off the inside of the oil filler cap.
Drive it a few days.
Remove cap and touch your finger to the condensation inside the cap.
Taste it.
If it is sweet or has a taste, it is antifreeze.
If it is tasteless, it is regular water condensation.

With regular driving 5 miles or more per one way trip on a semi daily basis or more, you wont likely have a non-antifreeze condensation problem.

Being for sale at a dealer lot would invite non-antifreeze condensation problems.

How bad is the external oil leak discovered by the oil change place?

And dont be fooled into thinking the oil place would not suggest repairs they do not do. Did you make it out the door without someone suggesting where to get it fixed?

 

The truck sometimes goes without being driven for days. I'll do what you suggested DoubleO7 and check the taste.

The oil leak is about 1/2 quart leaking per month. Mostly all on my driveway which is why I noticed it. I took it back to the oil change place and they topped me off, and said it was a 1/2 qt low and it had been approx 1.3 months since the oil change.

 

I would get a can of cleaner and clean underside best you can & run it thru the car wash to figure out exact location of oil leak.

 

Uggggh. I was thinking about that, but I was under there today and it looked like caked n baked oil over a large area.... not sure how bad that means it is... but im going to take it to a trusted shop and have them evaluate it.