How to determine bad heads, bad rings, or both?

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Myke

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So I have 148k miles. I haven't noticed any powerloss since I purchased with with 130 miles in Nov 2016. I didn't pay much for the Jeep so went in with an engine replacement/rebuild in mind.

Normal driving there is some blue smoke out the exhaust but not very noticeable. When going up an extreme incline I will start to burn oil out the exhaust pretty heavily until I get back on the road and drive for 20-30 minutes. Then it goes back to "normal" minimal burning of oil.

It looks like a lot of smoke when on an incline but I tend to only need to top off 1-1.5qts of oil between oil changes (3000 miles).

I haven't noticed any power loss from when I purchased it. This has been going on for roughly 6-8 months now and has not gotten worse in terms of how much blue smoke is coming out the exhaust.

I have recently in the last month been losing coolant. I keep an eye on it so never overheats or gets low enough that my heat stops working but I would say I'm topping off the coolant overflow once a week. It'll go from the seam down to 1/4" left in the tank. I do not see any leaks from the radiator, water pump, radiator hoses, etc.

Does anything stand out about this? Any suggestions on where/what to start testing to find out what needs to be replaced.

My game plan is:

  • Pull out spark plugs. rotate the engine so that the first cyl I'm testing is at top dead center.
  • Put the car into gear and set the hand brake to prevent the engine from turning when I pump air into the cylinder. Start with the regulator off so there is zero the pressure coming in. Connect my air compressor, and turn the regulator to pressurize the cylinder.
  • Write down what the leakage percentage is.
  • Then, open the radiator cap, the oil cap, pull the dipstick, and take off the air cleaner. To listen from all these points and see if I can hear air escaping.

  • Air whistling out of the intake probably means a leak around the intake valve?
  • Air coming out of the exhaust or exhaust mani indicates an exhaust valve leak?
  • If I hear it whistle out of the PCV valve, oil pour hole or dipstick is a sign of that air getting past the piston rings - i.e. cooked rings?
  • And if any air bubbles out through the coolant, it indicates a head gasket leak?

Is this sufficient or should I do a dry/wet compression test too?


Then once I know what's worn I can figure out if I just need new heads, a head gasket, or if it's time for a full rebuild/replacement motor?
 
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Myke

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Are you leaking any oil?

I believe there is a slight drip from the oil-p sender but I was going to just swap that out regardless. I had a leak from my water pump so i replaced it about 4 months ago. There is a good chance the oil-p leak was just coolant mixing with grime/dirt and traveling back to that area while driving. I need to reinspect again.

I've got off Fri-Mon this weekend so I'm going to be pulling my front axles (killed them running no swaybar for a while). See if I can get Napa to warranty them if not I'll buy another set. Last time went with the Napa(cardone) remans. Thinking about getting limiting straps so I can run with no swaybar on the trails again.

While working on that this weekend I'll perform the leak down and compression tests.
 
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