Did some searches but did not see any discussion on this issue.
I am a member of a few other LH platform clubs and we are seeing some rod bearing issues with the 3.5L engines. Random rod bearing knock that does not appear yet to have a cause. Well maintained engines, regular oil changes etc. Rod bearings tend to spin and wipe out the rod and crank. Some have been in the 100-150k range with some owners well over 200k with no issue. Years are also random. 99-01 did have an oil cooler that was deleted 02 and up yet we have seen failures with and without.
Anyone have some input/discussion ?

 

I don't claim to be an expert and this is just my opinion.
I've been in the automotive industry for the last 30 plus
years and learn something new every day.

I've had a fair amount of experience with the chrysler 2.7 ,
3.2 and 3.5 in their LH body cars.

I had a 2.7L , my personal car , seize up at an idle with no warning.
These are known for consuming coolant and it was my fault for not
fixing that problem , which led to the engine failure.

Back to the original thread topic . It seems as if Chrysler was after
some additional fuel mileage and HP when they built the 2nd gen.
3.5L engines. I have a 183,000 mile 3.5 that I put a set of rod brgs
in at 172,000. I had just purchased the vehicle and noticed an ever
so slight knock on start up only. After pulling the pan and looking at
the bearings , only the upper half was just starting to see copper, the
bottom half looked good for the miles.
If you look at the bearing width vs. the crank journal and conn. rod
width , Chrysler could have very easily used a bearing .100 wider to
help with the load carrying capacity, but that causes more rotating
friction. I'd rather give up 1 mpg than have to think about loosing
the bottom end.
I had nothing to loose but my time and the cost of a set of rod bearings , so I polished it up and put it back together.
Now just a little more rambling,,,,,
- People think their doing a good job by going to a quick lube every 3000 miles . The oil they use it the cheapest crap they can buy !!
I'm not here to sell oil but you get what you pay for " most of the time" do your homework , even some of the top advertised synthetics aren't that great.
- Run a premium oil filter
- And from my own experience , when you have " ANY " amount of
coolant consumption , address it immediately.
I honestly believe because they have a weaker than average bottom
end that all of the above is super critical.
Again , Just my humble opinion and to end on a positive note , if I didn't enjoy driving my car and I really do , I'd never put this kind of
work into it.

 

Thank you for taking the time to reply. Agreed a wider bearing may have fit and MPG is the mfg goal.
Maintenance is key no doubt.

 

I have a '99 concorde with a 3.2 I purchased about 2 years ago with 80K miles. At 100K, i replaced the TB/WP. Car ran with absolutely no issues the time i had it. At 103K, i heard a tapping. Long story short, ended up being #2 rod bearing. It was totally shot and the crank and rod were toast too!! I pulled the other caps and they were just beggining to show copper. One other thing....this engine was absolutely spotless, i mean, there was no sludge or other other evidence that would suggest neglect or lack of maintenance.

 

Sorry for your knock but thanks for the info.
Starting to see this more and more. (3..2 and 3.5 are identical except for bore size)

 

That sucks to say the least. It seems like it's a real crap shoot to get a good one or not . There could be other factors why these loose the bottom end , like over reving the engine , cold start up and taking off immediately ? I'm kinda reaching here but I 've read many an article
that if you let your car run 1-2 minutes before driving that you'll get
a 100,000 more miles from the engine. And I'll still strongly advise to
fill the oil filter before installing it on any vehicle.

Mine just turned 187,000 after putting the rod bearings in at 174,000.
No problems so far. I run an extremely high quality oil with some
EP additives and won't get this thread into an oil debate.
I have a scan gauge and this 02 Intrepid still gets 30 mpg highway.
I drive the car 90% of the time and the only other thing I've noticed is that they have a low idle rpm when in gear , roughly 650 . This may be way over thinking but when I'm in traffic sitting for any length of time , I put the car in neutral and the rpm's go up to 750. I have no
mechanical oil pressure gauge but it would be interesting to see the
difference.

If the car is solid , keep your eye out for a wrecked one you can buy for salvage. I just bought a totaled 04 with a 90,000 mile 3.5 HO for
$300 . It's just a matter of time before I'll have to swap it out.

 

Idle speed is set low on these engines and lower limit of oil pressure is 5 psi. Still gathering information, thanks for the reply.
Further discussion here :Chrysler 300M Enthusiasts Club • View topic - 3.5 Engine Connecting Rod Bearing Information/ Analysis

 

I've called a number of boneyards and have a couple of a ads out but have yet to locate a 3.2 or 3.5 for my year model (or, '98 thru '01); plenty of 2.7's though. We'll keep looking though, or, bite the bullet and purchase a reman; as you've said, a crap shoot either way you look at it.

 

Salvage yards will want $1200 -$1500 for a decent engine with over a 100,000 miles on it. If you do get one from a salvage yard , ask them for
the vin # and get a car fax before buying, mistakes on mileage do happen.
I'm on the road working M-F so I was very Lucky to find this one private
sale. The car was an ex police cruiser and I believe was well maintained as
when I removed the oil filler cap , there was zero brown varnish, and the
engine sounds very quiet. When or if this engine makes into the 02 I'm driving, I'll still pull the pan " when out " and roll a set of Clevite 77 rod brgs in. Good Luck