Rattle at start up

[ShafferNY]

Our 06 has a rattle at start up. It sounds just like a couple transmission lines rattling, or a heat shield that's loose. I've looked under it and found nothing.

I believe it's something in the valve train or time chain componets because it goes away about 30 seconds after start up. It's as if it disappears as soon as the oil pressure builds up.

How exactly do the timing chain tensioners work? Are they hydraulic?

Any idea what exactly this could be?

BTW. It came back from the garage with this rattle after they performed the TSB on the valve train. At the time I didn't think anything of it, because it went right away.

The good part is, I haven't seen a CEL!!!

TIA

 

[k99jk99j]

mine has done this since new. i attribute it to piston slap or timing chain tensioners coming up to full pressure. i am not worried about it since i have heard alot (not all) of 3.7/4.7L's do it with no ill effects.

 

[ThunderbirdJunkie]

Yeah, the tensioners work on oil pressure...how many miles are on it?

 

[ShafferNY]

Just bumped over 40K

 

[tjkj2002]

They could have messed up on install if the timing chain tensioners delaying there pressure build up.Take it back and have them fix it on there dime.

 

[ShafferNY]

I believe the work they did on it had a 12 month, 12k mile warranty on it. If not, our aftermarket warranty should take care of it.

Just curious. Would this cause any other componets prematurely failing as a result of this?

The reason I ask is because this engine has been messed with so much, I'm questioning the longevity of it.

 

[ThunderbirdJunkie]

Everything that is a repair carries a 12/12 warranty by law.

 

[tjkj2002]

I believe the work they did on it had a 12 month, 12k mile warranty on it. If not, our aftermarket warranty should take care of it.

Just curious. Would this cause any other componets prematurely failing as a result of this?

The reason I ask is because this engine has been messed with so much, I'm questioning the longevity of it.

Timing chain stretch,tensioner pad wear(they are plastic),out of time cam/crank(big problem,major damage).

 

[ShafferNY]

They could have messed up on install if the timing chain tensioners delaying there pressure build up.Take it back and have them fix it on there dime.

If you start up the engine cold, it makes the rattle noise. After approximately 30 seconds it's gone. If you shut the engine off and start it back up, it doesn't do it. This is what made me think the problem was ralated to the oil pressure.

Knowing the vehicle history, I went looking through the FSM for componets which could be the culprit and the timing chain tensioners is what made sense logically. I just wasn't 100% sure how they worked.

A post about a quarter of the way down this thread seems to explain it, though it's intended for the 4.7L V8.

Timing Chain Assembly

Boy. It just sounds like this Jeep is going to be a problem child forever.

 

[ShafferNY]

Thanks for your help Troy.
Much appreciated.

 

[k99jk99j]

very common noise that is supposed to be normal, here are two examples! i can find more if you need! mike

here is four that have rattled since new
http://www.jeepforum.com/forum/f28/cold-engine-tick-update-664888/


post #21 is from a dealership tech he seems to think it is the cat covertor warming up?
http://www.jeepforum.com/forum/f28/cold-engine-noises-3-7l-282340/

 

[moparman]

I hear that on my Jeep occasionally, not worried about it. Mopars have been making hydraulic lifter-like noises for forever. You should have heard my Neons starting up could. One would thought they were ready to blow up. They never did. My last one is still running around Minnesota with 150K miles on it.

 

[moparman]

BTW, that other Jeep Forum isn't as good as this one. A few good people but not the same technical depth. I know that some of us are on both. A lot of newbies find that one first because they don't know what a KJ (or KK) is.

 

[Mangate]

What about a bad non-return valve in the oil filter, or incorrect filter?

 

[kb0nly]

I hear that on my Jeep occasionally, not worried about it. Mopars have been making hydraulic lifter-like noises for forever. You should have heard my Neons starting up could. One would thought they were ready to blow up. They never did. My last one is still running around Minnesota with 150K miles on it.

X2... I had a 95 Neon that sounded like it's motor was shot on a really cold morning, but after it warmed up it was as quiet as a luxury car....

My KJ has that same 20-30 second period of more than normal noise at startup when its cold, on a hot day, or after the engine was just run, it doesn't do it. but let it sit over night and a cool morning the next day it has a little clatter to it until the oil gets a flowing!

The 3.4 in the Pontiac minivans does the same thing, the 97 Montana we had did this too so i guess i wasn't that surprised to hear a little noise on the KJ when she fired up. The 3.4 was worse, clank clank clank clank, sounded like it was going to blow up the lifter noise was so bad, but after less than a minute it was gone.

I also notice on the KJ it has more to do with the amount of time it sits then just temp. It can be 80-90 degrees here and let it sit for 8 hours or more and it will make a little clatter noise for 10-15 seconds even on a warm day, i attribute that to the oil being pumped up through the entire engine and getting circulated before everything smooths out.

Considering the track record these 3.7's have, and the guys with 200k plus miles on them and they have had that noise since new i'm not going to worry about it. I found one mention on a small Jeep forum where the owner of an 02' has 270k on his, he is a traveling salesman and drives it 7 days a week across the country and back, and his has been making that noise since day one at 30 miles on the clock.

 

[Marlon_JB2]

I don't know of a 3.7L that doesn't make that cackle / rattle noise at startup. Heck, mine does it. Some are louder than others though, take my sister's for instance... hers is very noticeable, mine is there, but you kinda have to listen for it. Same goes for others I've driven at work, all make that noise!

 

[ShafferNY]

My '03 makes no noise what-so-ever and it has twice the milage, 84,000mi. My sister's '03 has over 100k on it and makes no noise either.

Our '06 never made a peep until it went into the garage for the TSB. That's what concerns me.

Honestly, if it would have made this noise at the time of purchase, it would still be on the dealer's lot.

 

[HoosierJeeper]

Was the 06 a lemon???

It kinda sounds like it...

 

[tjkj2002]

My '02 3.7 makes no noise at start up(besides the rather loud injectors firing,commonly mistaken for lifter noise).

 

[moparman]

My '02 3.7 makes no noise at start up(besides the rather loud injectors firing,commonly mistaken for lifter noise).

That might be what I am hearing, since the injectors are running rich at that moment.