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Old 08-12-2013, 08:58 AM   #1
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3.6 noisy at startup?

So far I have only gotten to drive on the weekends (still driving my other car until it's sold) and Saturday when I hoped in to move it after washing it in the drive, it seemd to be quite loud at startup and immediately got quiter.

I have noticed this before too.

It almost sounds like its very noisy until the oil circulates around or something. Otherwise it sounds fine a couple seconds after starting.

Perhaps I am just gunshy after hearing about early 3.6 problems.

Normal? No? It has just over 1,000 mi on it and its a 2013. Seems to run strong and otherwise, I like the engine. It's not TERRIBLE on gas and moves itself out of it's own way when needed.

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Old 08-12-2013, 09:07 AM   #2
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So far I have only gotten to drive on the weekends (still driving my other car until it's sold) and Saturday when I hoped in to move it after washing it in the drive, it seemd to be quite loud at startup and immediately got quiter.

I have noticed this before too.

It almost sounds like its very noisy until the oil circulates around or something. Otherwise it sounds fine a couple seconds after starting.

Perhaps I am just gunshy after hearing about early 3.6 problems.

Normal? No? It has just over 1,000 mi on it and its a 2013. Seems to run strong and otherwise, I like the engine. It's not TERRIBLE on gas and moves itself out of it's own way when needed.
If YOU think its loud try going to synthetic oil. Both my '10 and '12 sounded quieter on start up after going synthetic. At least to my finely trained ear (Nyuk)

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Old 08-12-2013, 09:13 AM   #3
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very possibly the secondary air pump if these engines have one. It is normal for the secondary air pumps to run on cold starts. if there are leaks the pump can sound louder. the pump is for emissions regulations.
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Old 08-12-2013, 09:18 AM   #4
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Mine does the same thing. It sort of whines and ticks but only for a second then it goes away. Mine also seems to run shitty for the first 30-45 seconds if I take off immediately. These 3.6's really seem to like running hot.
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Old 08-12-2013, 09:45 AM   #5
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Some do and some dont rattle at startup after sitting. Most people on this forum dont seem to be too concerned about it. But I would really like to know the root cause. Until then there is no way to know if it could be a problem long term.
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Old 08-12-2013, 10:20 AM   #6
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Im not too worried about it for now. I will change to synthetic shortly after a little break in time and see if it helps. I guess I expect a modern engine in a brand new vehicle to be church mouse quiet, but maybe that's not realistic.

I would be more worried about it if it did not quiet down so quickly.
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Old 08-12-2013, 10:49 AM   #7
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From what I read its just a little valve clatter on start up because the oil is circulating up there since it drained. Completely harmless and normal. 2012 wrangler 10k miles
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Old 08-12-2013, 10:54 AM   #8
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Im not too worried about it for now. I will change to synthetic shortly after a little break in time and see if it helps. I guess I expect a modern engine in a brand new vehicle to be church mouse quiet, but maybe that's not realistic.

I would be more worried about it if it did not quiet down so quickly.
Since a lot of engine wear occurs at startup I would still like to know what is causing it. Even Harley Davidson engines are fairly quiet at startup but rattle like hell when hot. But that is just a characteristic of that engine. Let us know if the synthetic helps.
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Old 08-12-2013, 11:23 AM   #9
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Mine ticks at startup too. I switched to synthetic with no change. Castrol Syntec since Mobil one doesn't meet Chrysler specs.... Yet.
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Old 08-12-2013, 11:26 AM   #10
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I thought I read somewhere that the filter doesn't have an anti-drainback valve. So, the oil pump needs to fill the filter up each time you start before the valvetrain gets full oil pressure? I am not sure.
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Old 08-12-2013, 11:36 AM   #11
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You think the 3.6 is bad you should hear a late model hemi after it sits a week

Generally what happens is a lifter is on the top of a cam lobe and the hydraulic lifter bleeds down a bit so you get some clatter.

Pretty sure there is some kind of anti-drainback on these, when you change the oil on the 3.6s there is quite a bit of oil in the filter housing even after sitting overnight. It would be empty if the oil drained right back out of the filter. All it takes is a little air in the oil to make the lifter clatter though.

I have noticed mine clatter a bit on startup, also sometimes it will idle pretty rough for a few seconds on a cold start. Lot of the rough running part has to do with the cam phasers, takes a few seconds for everything to get in line. Plus you have emissions doing their thing to get the catalytic converters lit off as quick as possible.
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Old 08-12-2013, 12:04 PM   #12
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I thought I read somewhere that the filter doesn't have an anti-drainback valve. So, the oil pump needs to fill the filter up each time you start before the valvetrain gets full oil pressure? I am not sure.
The anti-drainback valve is in the block. At least that is what I read on another forum
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Old 08-12-2013, 12:16 PM   #13
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Ah ... thanks guys.
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Old 08-13-2013, 02:03 AM   #14
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Mine always clatters loudly immediately upon startup if it's been sitting at least an hour, and then completely goes away in about 2.5 seconds. Switching to synthetic had no effect.

Supposedly normal...but I've never heard any other vehicles do this and certainly none of the previous vehicles I've owned did this.
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Old 08-13-2013, 06:11 AM   #15
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Mine always clatters loudly immediately upon startup if it's been sitting at least an hour, and then completely goes away in about 2.5 seconds.
Both of ours do the exact same thing.
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Old 08-13-2013, 07:50 AM   #16
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I also have the same thing at start up. Synthetic didn't make any improvement. Inside my garage it's downright loud for a second or two. It find it extremely annoying for an otherwise great engine. Also the metal on metal rubbing or whatever it is would have to take its toll over the years. Every once in a while it won't do it. Strange?
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Old 08-13-2013, 07:58 AM   #17
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My '12 JKUR does exactly the same thing, as does my '06 H3 (3.5L). I've got 125k on the '06 and not a problem so I am not concerned about the noise.
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Old 08-13-2013, 08:13 AM   #18
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My 2013 did this because I only drove it once every few weeks. After I took it on a 4K mile vacation she purrs like a kitten. I also switched to synthetic oil.
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Old 08-13-2013, 08:17 AM   #19
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Thanks guys, I won't worry too much about it. Now if I could just get to drive it some. Does anyone want to buy a 2004 GTO?
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Old 08-13-2013, 11:18 PM   #20
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Just filled up with 6 quarts of fresh Mobil1 synthetic & no difference to the startup clatter...just the nature of the beast. I'm not worried about it, it only lasts for 2 seconds while there's no load on the motor. I don't see it having any effect on long-term wear & tear.
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Old 08-14-2013, 02:24 AM   #21
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Confirmed by Wikipedia

"Frequently, the valvetrain will rattle loudly on startup due to oil draining from the lifters when the vehicle is parked. This is not considered significant provided the noise disappears within a couple of minutes, typically it usually only lasts a second or two."

Hydraulic tappet - Wikipedia, the free encyclopedia
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Old 08-14-2013, 05:19 AM   #22
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After some research I found this on another forum. Makes sense to me.

There appears to be two problems. First is a hydraulic lash adjuster problem that affects one of the adjuster bores and allows the oil to bleed out before it can pump up the adjuster (note that a Pentastar does *not* have hydraulic lifters -- the lash adjuster's sole purpose is to push up slightly on the cam follower to keep its roller in contact with the cam so that it doesn't make noise). This problem is annoying but not actually going to cause damage to your engine.
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Old 08-14-2013, 08:16 AM   #23
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Quote:
Originally Posted by MikeK46 View Post
Confirmed by Wikipedia

"Frequently, the valvetrain will rattle loudly on startup due to oil draining from the lifters when the vehicle is parked. This is not considered significant provided the noise disappears within a couple of minutes, typically it usually only lasts a second or two."

Hydraulic tappet - Wikipedia, the free encyclopedia
Wikipedia- Please don't believe everything on Wikipedia. Anyone can post anything at anytime. Some good stuff, some not so good or accurate stuff. They do try and correct erroneous information as fast as they can but it is a huge job and some misinformation does get posted.
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Old 08-14-2013, 11:32 AM   #24
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Most of us believe the things we read on forums, is Wikipedia any better? :-)
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Old 08-14-2013, 04:12 PM   #25
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Most of us believe the things we read on forums, is Wikipedia any better? :-)
Nope! Jeep forums are always 100% accurate, right? They're on the internet so they have to be correct.
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Old 08-14-2013, 04:42 PM   #26
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Mobil1 seemed to fix it for my '13 but now I have a squeak, probably from the belt or pulleys. I hope it's not always going to need attention 💩
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Old 08-14-2013, 04:48 PM   #27
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Mobil1 seemed to fix it for my '13 but now I have a squeak, probably from the belt or pulleys. I hope it's not always going to need attention 💩
You may have the infamous water pump squeak.
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Old 08-14-2013, 05:02 PM   #28
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I too get a little valve clatter on start up. There's 24 of em in there, bound to be some noise. Much more noticeable when in the garage though.
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Old 08-14-2013, 05:19 PM   #29
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You may have the infamous water pump squeak.
Whatever it is, neither the pitch nor tempo change with rpm...freaky
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Old 08-17-2013, 01:55 AM   #30
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Since switching from Castrol Edge to Mobil1, sometimes I get the clatter in the morning and sometimes it's perfectly quiet! What's up with that? LOL...Pentastar has a mind of it's own is what it is.

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