Messrs Putney and Beasley : suggestions on timing chain replacementinterval for 2.7L V6

Gents,

I'm approaching 230,000 km (143K miles) on this 2.7L V6. No indications
of any problems so far. But the known issues with the 3 timing chain
tensioners (sludge related I believe) plus the catastrophy of a broken
or skipped chain is something I'd like to avoid.

Any advice on when to replace this stuff on a pro-active basis ? I'm
guessing the water pump would get done at the same time.

Or perhaps this isn't as big an issue as I'm led to believe from all the
stories on the internet ?

Thanks...Phil

 

Isn't there a procedure to measure the chain/sprocket wear and go from
there?
But I wold have changed the chain long ago.
Bob AZ

 

I haven't seen any problems with timing chains or that many sludged up
engines outside of the cust just not maintaining them properly. I don't even
know if there is a recommendation for replacement of the chains. Probably
not. I will check when I get to work. Anyway I own a 2.7 and I expect the
timing chain/guides to outlast the water pump so when the water pump fails
on mine..... that is when the rest will get replaced. If you don't maintain
your vehicle then I couldn't answer your question because dirt/sludge and
all that good stuff is what wears things out prematurely.

My opinion

Glenn Beasley
Chrysler Tech

 

Heh heh! First - yes - absolutely if the chain gets replaced, so the
water pump.

Good question. Yes - I believe the chain will outlast the water pump -
a shame they designed it like that, but that's the modern
engineering/automotive world with all the governmental and marketplace
pressures to integrate and compact everything. I have seen claims by
some on the internet (yes - purely anecdotal) that water pumps have
failed by locking up and resulting in major damage and expense. That
gives you a nice warm fuzzy doesn't it!

Mine is right at 160k miles now. I have casual plans to replace the
chain (tensioners, etc.) and water pump, but it may be another year or
two before I get a roundtoit, fully realizing that there is some risk
which I accept. If the stories are to be believed, it's all a crap shoot.

However I also believe that things that are done intentionally by the
owner (using certain anti-sludge oil additives or synthetic oil) or
inadvertently (mostly highway driving vs. lots of short-trip
stop-and-go) will cut much of the risk (and sludge). On the other hand,
I'm not sure there is much you can do to guarantee that the water pump
isn't going to randomly fail (other than do all you can such as replace
coolant and be sure to use the right stuff - G-05).

Life's too short to worry too much about it - other than just being very
prudent with the maintenance and letting the chips fall where they may.
What's that they say about luck: "I don't believe in luck, but those
who prepare seem to have more of it."

IMO...

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Why? I'm not saying you're wrong - I just would like to hear your
rationale.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Not that I've ever seen. And even if there was, if you disassembled the
vehicle enough to just get at the timing chain so that you could measure
it, you might as well just carry on and replace it at that point.

The chains are supposed to be good for the life of the engine. There is
no replacement interval recommended, unlike timing belts.

One of the failure modes is that the main hydraulic tensioner gets
sludged up and stops working, which eventually leads to failure of the
chain, or the chain skips a tooth or two.

Another failure mode is the water pump seizes which then leads to a
chain failure. The water pump is inside the engine. So when it starts
to go, it isn't like you can hear it start to get noisy before it fails
like you can on most cars where the pump is external to the engine.

Phil

 

Thanks Bill. I guess I'm more or less thinking the same way you are but
I was looking for a reality check.

The majority of my driving has been highway so that avoids the short
trip/low temp sludge mode. The PCV valve gets replaced regularly and I
clean out the PCV hose and heat exchanger. I occasionally get coke
particles out of the PCV hose so that tells you something about how hard
this engine can be on oil. That's another important anti-sludge PM with
these engines.

On the other hand highway driving exposes the oil to longer periods of
the high temps on the heads, which can cause sludge/varnish formation
locally in the hot areas. This is apparently why the manual classifies
frequent trips at sustained high speed (highway speed ?) greater than 45
minutes in duration as Severe Service. And hence, the shorter oil change
interval.

I change my oil every 3000 miles when using non-synthetic. I generally
use Valvoline Maxlife High Mileage which contains a healthy does of
extra detergent and it also contains about 20% synthetic. When I use
full synthetic I may let the oil change interval go to 4000 miles. I
always use a high quality filter like Napa Gold (Wix) or a Purolator
Pure One. The filter is also over sized (PH43 size vs the standard PH16
size). So in the oil dept, I've done everything possible and then some.

In the warmer months I use Esso Extra 0W-30 motor oil. This is a full
synthetic (100% PAO - Group iv oil) with exceptionally high levels of
detergent and additives. And it is significantly cheaper than all the
other well known full synthetics. Despite the 0W designation, this oil
is actually thicker than most 5W-30s at all temperatures except when the
temps are below perhaps -20F. At real low temps it maintains a thinner
viscosity than a 5W-30. But I never see temps that low here.

I'm going to pull the valve covers in the spring to evaluate the
sludge/varnish accumulation on the top end. I almost hate to do it
because that job is such a pain on these cars. It'll probably take me a
full work day to get everything apart and back together.

Phil

 

I also have a 98 Intrepid with 264000 km and the 2.7 engine.
I have had no problems with the engine whatsoever. I do a lot of highway
driving, changed the oil about every 12000km during its life. 10w30 in
summer 5/30 in winter, Engine flush at the time of oil change.
I, and my trusted mechanic think to leave well alone until water pump goes.
I change coolant yearly not wait for the so called 5 year expiry.
Only problem will be that this car has no resale value and a waterpump
change would exceed its value otherwise.
Its a great car I am seriously thinking of buying a back up 2002 Intrepid.
Keith

 

What year is your car? I ask because there was a design change to the
PCV hose that will reduce or eliminate the coking up of the PCV hose
(which, as you point out, will completely clog up without periodic
cleanings - the deposits actually will also dissolve the rubber elbow in
the PCV hose). That change was done starting with the '00 MY (possibly
'01, but I think '00). The change is *easily* retrofit if you have the
earlier design - the part is around $30 and is quick and easy to do. I
did it to my '99.

I would take the long-trip driving over the short-trip stop-and-go
driving any day. I doubt sludge will form with primarily highway
driving, but that's just an opinion (and reality has no respect for
opinions).

Careful with the oversize filters on teh 2.7L engine. The filter hangs
straight down, and sits right behind the front frame cross piece, and is
surrounded by the oil pan on all other sides. The standard size filter
is recessed above the frame piece and the oil pan enough to be well
protected from road debris. The extended filters will hang down too far
and be vulnerable to road debris. Chances of something hitting and
damaging it are maybe low, but if a rock or piece of metal just happens
to come off the road with just the right trajectory...

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Mine is an '01, built in late 2000. My PCV system has the little heat
exchanger built in. Even with that, I occasionally get a *few* little
bits of coke out of the hoses. Minor, but they're there.

I agree.

Yea, I'm aware of that. I do carry a spare filter, wrench and oil in
the trunk just in case. But the PH43 size really doesn't stick out all
that much. I'd love to use a PH8A size but that would hang down way too
much.

Phil

 

Yes, remove the chain, remove the master link, measure the total length of
the chain,
discard once it exeeds maximum variation. I almost forgot, you did remove
the master
link when you first installed the chain and measured it then , for a
baseline didn't you?

Ted

 

Is this a Bicycle we are working on or a car?

Glenn Beasley
Chrysler Tech

 

Most bicycles don't have master links in their chains either.

I posted that bit to illustrate the silliness of the request. Yes, indeed,
you can measure chain wear with the procedure, of course in a timing
chain there is no master link so getting one apart and back together
without introducing a weakness would be quite interesting, and in any
case since the OP oviously didn't baseline the original chain, any
measurements he took were he to actually be dumb enough to do this
would be useless.

If the OP used his or her head for a few minutes he would have
realized it was a dumb question. The usual way of measuring timing
chain wear is to simply look at the sprocket - a stretched chain
hogs out in between the sprocket teeth, and that is something that
is measured "by eye" If the timing sprocket teeth are in good
condition you can assume the chain is fine. And if the sprocket is
nylon/plastic coated it's going to wear long before the chain.

Ted

 

I used to build my own Bikes and all mine had master links, including all
the mini bikes I owned as a kid, I guess todays bikes dont have master
links.

I figured if someone is going to go thru the trouble to check for wear on
that particular engine they would replace the chains, guides and tensioner
regardless of stretch/wear.

Glenn Beasley
Chrysler Tech

 

I used to build my own Bikes and all mine had master links, including all
the mini bikes I owned as a kid, I guess today's bikes don't have master
links.

I figured if someone is going to go thru the trouble to check for wear on
that particular engine they would replace the chains, guides and tensioner
regardless of stretch/wear.

Glenn Beasley
Chrysler Tech