Self destructing 4.2 inline six

Wow! It's criminal to see an engine self-destruct like that with only 100K on it. A 2002 with 100k would lead me to believe that it had a semi-pampered life. I hope that the replacement is a warranty job?

Rita

"Rita Ä Berkowitz" wrote

Yes, there is a "special policy" on these engines. I believe that this type of failure is covered up to 160K kilometers or

Ian

If they wanted a 4.2 inline six, they should have just put an AMC 4.0 in there. My 4.0 in my 90XJ is easily stroked to 4.7, has lots of lowend torque, and runs forever.

Hell yes, the thing isn't even broken in since this is most likely highway miles.

I would prefer the old Chrysler slant six (225), now that was an engine that was totally indestructible.

Congratulations. Inlines are more durable and have more ample torque than people give them credit for.

Rita

wrote

Please....I've worked on the 4.0 engine and they had/have their share of problems. It's also a cast iron pushrod engine that is quite outdated.

The GM inline 6 is all aluminum and this is the one teething problem they have had. Other then that, we "never" see them apart for anything. There are no leaks, the valve advance mechanism seems to be bulletproof, the few engines that have been apart exhibit "no" discernable wear on the cylinder walls, rod or crank bearings..etc.

This is the way of the future, like it or not. Guaranteed, there will be an all aluminum engine in the YJ's soon enough.

Ian

ahh, but what rocket scientist decided to put the front 4x4 axle shaft threw the oil pan....dumb.

"Brian" wrote

Why?

Ian

----- Original Message ----- From: "Rita Ä Berkowitz" Newsgroups: alt.autos.4x4.chevy-trucks Sent: Thursday, May 13, 2004 5:22 PM Subject: Re: Self destructing 4.2 inline six

The slanted tower of power!! Loved those old engines!

Doc

Twice as many mains as a V....

~KJ/TLGM

""Doc"" wrote in message news: snipped-for-privacy@adelphia.com... : : The slanted tower of power!! Loved those old engines! : : Doc : Ah yeah, putting points in them was the only bad job with the distrib. "down under" . The rest of the old Dart would fall off but the motor would be still running when it went the junkyard.

the same rocket scientist that decided to put IFS on a truck.

Dumb, meet dumber...

I guess everyone is opposed to progress?

IFS has a lot of qualities that a solid axle doesn't offer in the light to mid range truck: I.e SAI levels that are more in line with the suspension designs of today, so that camber and caster can be set for modern roads. Hence: non cupped and notched tires.

But I still believe for the heavy duty truck, nothing will replace the straight axle!

Axles through the oil pan: Even though I've yet to see this, I believe it was done for a lower center of gravity, and enhanced handling. If the engine moves with the axle on jounce and rebound, even better. A unitized suspension system, where there is no unsprung weight.

Just my thoughts, even though I've yet to see the axle through the oil pan.

Refinish King

No, they just don't know any better.

True.

No doubt!.

Yes, these are the ones that flow through the crank. :) It's a work truck, who needs a center of gravity?

"Refinish King" wrote

Ian

You got me on that one. What vehicle is this in? Is it a solid or IFS? Anyway, thanks for the great pics.

Rita

"Rita Ä Berkowitz" wrote

This is a 4.2 inline 6 in a 2003 Chevy TrailBlazer. First picture is the left side of the pan "without" the front diff bolted to it. Second picture is of the right side of the pan "without" the shift mechanism for the front axle bolted to it.

Third picture is the left side with the front diff bolted to it....4th picture is the right side of the pan with the shift mechanism bolted to it.

This is an IFS vehicle. It's really identical in concept to all the other GM trucks other then the fact that there isn't enough room on the Trailblazers to have the front diff slung underneath the oil pan. So they bolted the front diff to the oil pan, ran a stub shaft through the hole in the oil pan, and have the front axle disconnect mechanism on the other side of the oil pan. From there, there are two halfshafts just like a FWD vehicle. So the engine and the front diff stay "put", and the half shafts move up and down and all around with whatever the suspension decides that it will be doing.

The new Cadillac SRV AWD vehicles are similar in concept. The Northstar engine in them has the same setup...front diff bolts to the oil pan. A real bugger to work on. But it's the way that they are all going.

Ian

I would have guessed that they would have to keep everything stationary since you are dealing with some very close tolerances, especially between the oil pan hole and the crank. Talk about squeezing every last bit of space.

Thanks again. I do see what you mean about being a bugger to work on. I'll bet it's a $1,500 job to change a leaking oil pan gasket? I guess I'm still living in the past were dropping an oil pan involves lifting the engine a few inches.

Also, my other concern with this design is how would hold up under a collision? If the suspension took a major hit by sliding into a curb would the axle/differential be forced into the crank? Or is there enough bracing in this modular design to withstand this abuse? My guess is that it would be fine, but I don't I really don't know.

Rita

Yeah, it would make little/no sense to have the engine jumping up and down with the suspension. The hole through the oil pan is solid, so there is no sealing that needs to take place between the oil pan and the shafts/diff/shift mechanisim.

The oil pan can be removed "in-car" on these. I haven't had to do one yet, in fact, I don't I've seen one leaking yet. You basically have to unbolt the diff and lay it off to one side and then pull the oil pan down. So it's probably not that big of a job. GM seems to have figured out how to seal up these engines, as I haven't seen any of them leaking oil or coolant yet. They do not have a split lower crankcase like the Cadillac Northstar, which means one less area for the engine to leak at.

This I do not know. It probably depends on the severity of the crash. I can see the oil pan getting damaged fairly easily.

Ian

This is good news if they have an easy procedure to remove the oil pan. The cast aluminum parts are great and very ridged so I don't think that leaking will be an issue since the mating surfaces are highly machined. Since a lot of these aluminum components are used for structural integrity or to hang heavier parts off of them, I still have a slight bit of concern about leakage. My concern probably isn't warranted

True, but I have to agree with you that if you don't see many/any coming into the shop this is great news.

Rita