That's right. OBD showed #0302 which is "cylinder #2 misfire". When i pulled the 1 month old plug to see what's the matter it was soaked w/green coolant.

First question, what's green coolant doing in my Jeep since there should only be Zerex G-05 in there. Answer: this engine is the Jasper remanned, installed Nov. '09, and my guess is the mechanic who installed it put the wrong coolant in there.

Second question, what's the most probable cause of the leak, head gasket or something else?

Final question, would having the wrong coolant in there have contributed to this problem?

Fortunately i purchased the extended service warranty w/the motor so, aside from having the motor itself covered, the labor is coverd too. Still a PITA

UPDATE:
Went out to put the plug back in and noticed green liquid pooled up in little spots/crevasses on the motor. i recall spraying the motor off a couple days ago, as we were in a lot of mud last weekend, and figured maybe the green was not coolant but rather soap from the spray wash that got on the plug as i was pulling it out.

Gently stuffed a shop towel in the well to make sure no green residue on walls of the well and then put a new plug in there. Immediate driving yeilded no difference. After about 1/2hr though it began running better albeit not 100%.

So now wondering, if not a problem of coolant leaking in there (which it may still be), what other possibilities? Coil pack? Is there a way to test that coil?

Other things to check?

TIA

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'04 Renny
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That stinks, sounds like a head gasket.

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Sounds like a cracked head possibly,take it back and have them figure it out.

As long as the green coolant is actually Ethylene Glycol you are good since HOAT coolant(GO5) is based off of EG coolant,just need to flush the system once a year instead of the longer interval for HOAT.

To answer your specific question on testing a coil:

Yes, the easy way to test a coil pack is to swap the offending/misfiring cylinder's coil with another on the engine. If the misfire code moves with the coilpack, then your problem is the coilpack. If the misfire remains, then your problem is elsewhere.

Remember to clear your codes first. Easy way if you don't have tools/readers: Unplug your neg battery cable for 15-20 minutes. That will clear all codes.

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-=Stock, but goin' places=-

04 3.7 Sport.
Auto Trans
Yokohama Geolandar AT/S 235/70/R16
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Sometimes the easiest solutions are the most elusive. Can't believe i didn't think of that. Thanx for reply tho.

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'04 Renny
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NP... rule of thumb: if you suspect a failing part that has lots of duplicates bolted onto the vehicle, move them around and see if the problem follows the suspect part.

Think: Relays.

You can spend a lot of time testing a given relay using approved technical process, voltmeters and little machines that go *Ping!* or, you can take an equivalent relay you know is good, and swap it.

_________________
-=Stock, but goin' places=-

04 3.7 Sport.
Auto Trans
Yokohama Geolandar AT/S 235/70/R16
Garmin GPS on RAM Mount

Mileage Trend: