Messrs Putney and Beasley : suggestions on timing chain replacement interval 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

Reply to
Phil T
Loading thread data ...

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

Reply to
Ace

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

Reply to
maxpower

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')

Reply to
Bill Putney

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')

Reply to
Bill Putney

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

Reply to
Phil T

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

Bill Putney wrote:

Reply to
Phil T

Reply to
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')

Reply to
Bill Putney

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

Reply to
Phil T

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

Reply to
Ted Mittelstaedt

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

Glenn Beasley Chrysler Tech

Reply to
maxpower

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

Reply to
Ted Mittelstaedt

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

Reply to
maxpower

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

Reply to
maxpower

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.