Well 2001 Dodge Ram 1500 Sport 5.9L 360 4x4 206,xxx miles did OBD2 ans shows mis on cly #5 and it is over heating and losing coolant. I am at a loss
so far I have replaced Wires and Plugs. Did a compression test came out
1. 160
2. 155
3.155
4.154
5.140 has oil on plug too
6.145
7.153
8. 155

 

Next step would be cylinder leakdown test. Might be able to rent the tool from the local parts store.... need compressed air too.

 

how does that work

 

Its a set of two gauges. One on the 'feed' side, where the air compressor hooks up, which tells you your input pressure. Another gauge on the 'cylinder' side, that tells you what pressure the cylinder will maintain. I usually dial input pressure to 100 pounds, so I can directly read leakdown percentage on the second gauge. Just as an example, with input at 100 pounds, and the cylinder maintaining 80 pounds, you would have 20 percent leak down. Seems like a lot... but, according to popular theory....... up to 25% is considered 'acceptable'...... (not in my book though.....)

The other neat trick here, is you can HEAR where the air is going, be it out one of the valves, (and you can even tell which one.....) or, around the rings.

If you are within spec, and don't hear much of a breeze out the intake, or exhaust.... then you just have some ring that are getting questionable, but, that wouldn't give you a miss. Your compression numbers look ok, and even dodge says minimum pressure is 100PSI on a compression check.... so.... rings are probably reasonable, if not good.

Unfortunately, that leaves..... valves. This test will tell you if that is the problem, and even which one, or both..... if it is indeed valves, and leakdown is greater than 25%, (or fairly close), time to yank the heads, and have a look at those nice cracked valve seats our trucks are famous for.

 

my bigest problem is where is the oil coming from when i pulled the new plug to do the compression test it was coated in oil on the top and bottom of the plug.

 

Plug not firing because of no spark or fuel injector plugged and oil will load up plug. Could be a faulty injector. If you have a stethoscope you can hear the injector click open and close. Could also have a bad plug wire shorting out to ground. Easy to check wires at night beause you will be able to see the shorts. You may have to jiggle the wires.