OK, I've been lurking for a couple of days and finally joined.

Have an '06 Caravan SXT (short wheelbase, not a grand). 3.3L V-6. Bought used with @ 42k on it, now has @ 79k on it. Has used Mobil 1 5W20 synthetic since 42k. Has had all required maintenances short of the radiator flush (which is pending funds and time -- also needs the inlet pipe from what I see).

For about a month or two it has been making a front (passenger side) engine noise that sounds like bearings or a rattling like bolts rattling in a can. Best I can describe it, it sounds exactly like a diesel engine running. Only at idle. Prominent when it warms up.

No engine lights or other issues there. No oil pressure light.

Today, I replaced the alternator and the decoupler pulley, as well as the serp belt tensioner and idler pulley. Alternator was OK but for time purposes I replaced both at once. I have a spare decoupler pulley and the special tool to remove it, and will put it on the old alternator as a spare once I get my vise mounted on the workbench.

About six months ago, the PS was whining on a trip. I had that fixed by flushing it and cleaning the reservoir filter. Water pump has not been replaced, neither has PS pump.

I'm thinking either resonance in the PS lines, or timing chain at this point. I'm ready to give up and take it to the mechanic.

It's the wife's daily driver, and while everything I've read here seems to indicate that the 3.3L gets louder with age and is non-threatening, it's annoying as heck to drive around sounding like a diesel!

Any thoughts? Anything I should try before I shell out any more $$$?

 

It's more like marbles in a giant soup can..lol. Sounds like timing chain slack. It used to be real bad on the older models after about 80K. I have yet to hear one under about 150K do it on the 01-07

 

have u tried to run the engine with the belt removed?

 

I've got an 05 which makes the timing chain rattle at only 110,750KM (not miles). I heard it on a couple other ones we test drove before buying this one, everything we drove had under 130,000km.

Is this the sound you are hearing?
http://www.youtube.com/watch?v=Cwn2ni_JqSc
It isn't my video but mine sounds EXACTLY like that. I tried switching to a thicker oil to quiet it down thinking it was lifters with no change in sound, and pulling the serpentine belt makes no difference in sound. Mine happens warm or cold, but when it's cold you have to try a bit harder to pick it out from the increased engine noise. The noise almost completely goes away if you rev it up over 2000, but until 2000 it just gets more frequent?

If yours (and mine) are the timing chain rattling around, what is the best route for repairing it? Replace the gears with the chain? Is the chain the same on all years of the 3.3L? I found some parts listings that only specify 01-03 or 01-04 for the chains....

 

That's exactly it! That low, guttural rattle. It goes away on acceleration and isn't there cold. I didn't run it with the belt off when I did the alternator yesterday, but it's exactly that sound.

I highly doubt it's stuck lifters simply because I am meticulous with my oil changes and, using the Mobil 1 for so long, there shouldn't be a problem there. Plus, stuck lifters should sound from start-up and get worse with acceleration, I would think, and this doesn't do either.

I'll be interested to know if there's a fix or if doing the timing chain will even help if anyone knows!

 

Weird! I wonder why this one is doing it so early? What should I get to replace the timing chain -- I've heard of an o-ring in the timing cover that I should acquire, along with the regular chain parts. Anything else that's a must-buy?

I'm probably not going to do that job myself, since I don't have a garage and never have more than a couple of hours between needed trips to have it down for maintenance.

 

They got rid of the o-rings on the cover that used to be there.


Figure 1 - TIMING MARKS

Figure 1 - TIMING CHAIN COVER AND GASKET

 

try running the engine with out the belt, then. That will tell you wether if it is an accessory problem, or engine internal.

 

For the average DIY'er its a full day job, so if you can't spare the van for a day (and risk it being down longer if you find you need anything else mid-job) then you probably shouldn't do it yourself. We have a spare vehicle or two in my house and I hate paying somebody else to do what I can do myself so I'll be changing mine when the weather warms up. I figure if the chain is loose enough to bang on the cover it MUST be affecting the valve timing at least a little bit.

Based on my observations when van shopping this isn't early at all for it to be rattling.

What is the recommended parts list for the chain? Can/should the gears be replaced with the chain? Is it the same chain/gears for all 4th generation 3.3L engines?

I will be changing the water pump while I'm in there, and of course the oil pan and front cover gaskets need to be replaced as well, and I was thinking the lower coolant transfer pipe, anything else that should be changed? Oil pump perhaps?

 

Sounds good. Yeah, I think I will take this one to the garage. We have other cars, but I generally work in the street directly behind my house, so I can't do that detailed of a tear-down or leave it there.

Thanks for the info.

I'll probably do oil pump and water pump at the same time as well. I have the water pump already but will need to get the other pieces, including that inlet pipe.