tpm152

This is the final straw for me, I am switching to 5W-30 instead of 5W-20. I am willing to bet that this has at least a small part in these engines having early failure.

I would also be curious to hear from anyone who has torn down one of these 3.8s to see whether you could tell whether the main bearings have lead in them. During my time at GM they were experimenting with new types of "unleaded" bearings (don't ask me why because there is so little lead actually used in bearings compared to things like lead-acid batteries it's rediculous). Anyway every single time they tried bearings without lead in them almost every single time they wouldn't last anywhere even close to the life of bearing with lead in them. I am wondering whether this is an industry-wide thing

duneslider

What would 5w-30 do as opposed to 5w-20? I have thought of switching just cause it's easier for me to find.

humdezign

Well I talked to Chrysler and got a case# I will continue to keep this thread updated with the latest information. I'm deff going to be civil with them as I understand mistakes happen but in my opinion a 100% stock jeep (lift wheels and tires weren't installed yet) should make it way past 50k miles. I do alot of highway miles so I think the 2007-2008's are just now starting to see the results of a defect and I worry that this is just the beginning of alot more posts to come. I can't emphasize enough, this was my baby and I treated it that way. I thought a well cared for jeep should see 200k at least???

I have begun an extensive search for similar cases to compile a list of known cases and I will merge the data and provide it here soon to help others that find themselves in my position.

I just got separated from the ole lady and money's been real tight so all I can do is hope jeep makes this right or I'm screwed. Can't afford to fix it and if it's just going to happen again in 50k I'm not sure it would be wise to.

Wish me luck on my case guys, I'll keep y'all posted.

Also I have a TF 2.5 with coils, adj track bar, and spidertrax spacers all new in box from Dave that if worse does come to worse I'll need to unload so I can buy an a to b car to get to work.

humdezign

Also i was told by service all they did was crank it and by the sound no further inspection was needed. If there is proof of incorrect assembly can I trust they will document it properly and if so how should I tell them that I want that done? There charging me 150 for inspection already and to my knowledge all they did was turn the key and look at the dipstick. I want the dealer on my side so any advice on how to proceed from someone with experience with dealers is greatly appreciated,

Cheers,
Jason

tpm152

The second number in the oil weight (the 20 or 30 in 5W-20 and 5W-30) is the effective oil viscosity at 100 degrees C (normal engine operating temperature). The reason why many companies are moving toward engines running on 5W-20 instead of 5W-30, is once your engine is warmed up and you are driving on the highway, the less viscous oil is supposed to slightly increase MPG because it creates thinner boundary layers (oil films) on all of the fluid bearings (which includes just about every single bearing in an engine). This results in less theoretical "pumping loss" from each bearing (meaning less parasitic power loss and higher efficiency). The trade-off of course is that thinner oil boundary layers (oil films) means that there is less of a buffer preventing metal to metal contact when you have to run high RPM to accelerate up a hill or pulling a trailer.

Just for your reference the first number (5 in both 5W-20 and 5W-30) is the "cold" viscosity. This means that when you cold start the engine, there is absolutely no difference between 5W-20 and 5W-30.

duneslider

Thanks for the info. If I was worried about gas mileage I would buy a prius. I am gonna switch next time I buy oil. I have been running mobile 1 since break in was over, hope it keeps my jeep healthy!

07JKX

mine made a terrible noise on a cold start the other day... been fine since then. I amy have parked it funny to allow the oil to drain out and caused a dry start.

58000 miles on my 2007 motor. It better last me at least till 150K miles

jcs07jk

I have a 2007 and I have the lifetime power train warranty. I thought if you bought a jeep product before the warranty went into effect in 2007 they gave you it When did you buy your JK?

ROKLIMO

Mine has 85k miles on it and sounds like two skeletons fighting in a shitcan. Won't be long for me.

Phantasm

My dealer does them free for the life of the vehicle (State inspections too) Of course I'm moving 240 miles away in 2 months