engine noise at start up, lasts about 5 seconds, cant be a rod knock (or god help me)

audible clicking noise within the first 5 seconds of a cold start up, goes away immediately when throttle is applied or 3-5 seconds go by

maybe a hydraulic pump getting pressure after being cold? Ill try to get a sound clip next time i start it up and the noise is present. dealer had oil changed when the vehicle arrived and its only got 8500 miles on it, so perhaps this is normal? Didnt hear the noise until earlier today after I let the jeep sit for about 3 hours in a parking lot and started it up. It didnt make the noise this morning however when the car had been sitting outside all night in 20-30 degree temps

LINK TO STARTUP
this time without the noise
http://meacrob.home.comcast.net/071119_04.wav

look at my post at the bottom for the lifter noise

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2006 TJ Rubicon
OME ZJ/LJ - JKS BL - MORE MML
Khaki 6 speed

lifters. it's a 4.0 thing. You should hear my boss's 100k mile TJ..it's BAD.

agreed
I have only 43K on my '02 and it knocked at cold start up
I swiched full royal purple syn. with a wicks filter and it stoped
keep in mind that if you are not like me and drive less than 5K a YEAR
this will get to be expensive REAL fast
The joke is
"I change my oil once a year weather it needs it or not"

so youre recommending getting the oil changed and seeing if the noise persists?

_________________
2006 TJ Rubicon
OME ZJ/LJ - JKS BL - MORE MML
Khaki 6 speed

well sorta
it has to do with the hydralic lifter not getting oil when it is cold and thick
if you look in the little book it will have 2 oil weights
1 for temps below 80* I think and 1 above
if it is cold out then the oil will be thick and it will knock
if it to hot for the thin oil then it will burn off

I live where the temps break 80* in December so I always run 10W30 but I also run the TJ VERY hard out on the trails
this is also why I run the full syn

so dont worry about it unless the noise starts to last upwards of 15 seconds?

_________________
2006 TJ Rubicon
OME ZJ/LJ - JKS BL - MORE MML
Khaki 6 speed

I can not hear it so it is hard to say
if it is just a few seconds of "tick tick tick" then it stops you should be fine
I would look to see what WT oil is in there ,probably 10W30
if it is cold where you are and the weather is not going to get warmer then look to see if there is a thiner oil RECOMENDED
BY JEEP for your engine
if so try that
mine stoped when I went to the full syn
it can not hurt a thing for you to do the same
it may have just been the wicks filter that is allowing more oil psi. in mine I dont really know
I know that I was in tellico ,Murphy NC last year and it was in the low 20's when I sarted the TJ
you could hear all the lifter knocking but mine did not do it
even jeeps with paper tags were knocking but my beat to heck TJ just started and was quiet
I was at a jeep jamboree

10W30 is what it says on the engine oil fill cap, but i just read from several engine oil companies that as long as the weight is the same (30) that its fien to switch from 10W30 to 5W30, and ill get a recording tonight or tomorrow, as it doesnt make the noise at every start

_________________
2006 TJ Rubicon
OME ZJ/LJ - JKS BL - MORE MML
Khaki 6 speed

As long as it doesn't sound like my XJ you should be fine

got a recording of the noise today, my dad was with me when I started it up, hes been around cars with mechanical lifters back in the day so he could identify it if it was a lifter or not. His diagnosis was that it was probably just one of the lifters at the very front of the engine. He said it might be normal because the I6 sits in the car at a bit of an angle, with the back end of the engine pointing down ever so slightly, so it might just take that much time for the oil to get into the front lifter when its cold outside.

anyways, I'm switching to 5W30 next oil change


heres the recording, you will probably have to turn it up to hear it well enough

http://meacrob.home.comcast.net/071121_01.wav

_________________
2006 TJ Rubicon
OME ZJ/LJ - JKS BL - MORE MML
Khaki 6 speed

I'll second the Royal Purple. I have been using that since my second oil change. My 05 LJ purrs at 35K miles. It has been tested repeatedly and always comes through faithfully.

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2005 Unlimited (LJ) Rubicon w/ 5.5" of total lift
Flat Fenders made by http://www.jpfaboffroad.com/

"Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin, 1759