Burning blue...cause?

[twmattox]

Is there a way to tell if my burning blue is from bad rings or bad valve seals (with the motor still together)? Hoping on a relatively easy repair and not a complete rebuild on my truck. Thanks-

[Zack172]

Yeah there is. First, do a compression test on your engine. Then, pour a little oil in one cylinder at a time and do another compression test. Don't forget to remove all the spark plugs before doing the test. If the rings are bad, the oil will seal them up, and your second reading will be higher than the first. Repeat that for all the cylinders. If its the valves or seals, the oil shouldn't affect the reading very much. If you have a helper its always nice. Hope this helps

[gsmikie]

what year truck ???? what motor ????? what trans >????? where is it burnning from ???? how is it burnning???

[twmattox]

Truck-81
Motor-360
Trans-?
Where burning from-out tail pipe
How is it burning-blue

I have never done a compression test before. If I have both bad valve seals and bad rings, will the oil in the cylinder show this too?