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-   -   Hemi sounds like diesel when cold (http://www.jeepgarage.org/f73/hemi-sounds-like-diesel-when-cold-71259.html)

jp467 02-04-2014 12:20 AM

Hemi sounds like diesel when cold
 
I think this is probably normal but I thought I would post to see what others think. I have noticed with the cold weather when backing out of my garage the hemi kind of sounds like a diesel for a few minutes until it warms up. I notice it as soon as I put it in reverse and the walls in the garage of course make it seem louder. Sounds almost like a rods knock. I did a little searching on the internet and it seems kind of common some posted its because of the short skirt on the pistons on these. Just wondering what others thought.

Ken Jacobs 02-04-2014 07:57 AM

Re: Hemi sounds like diesel when cold
 
My hemi does it also, I think it is piston slap. I hesitate letting the dealer look at it since it is running great other than the noise when cold.

Huskercory 02-04-2014 11:43 AM

My hemi has done that since almost day 1 in my 2008, which was 75000 miles ago. Sounds like total crap, almost like a loose rocker arm or bearing going out. Dealer has looked at it twice and said there were no issues. Was hoping that I wouldn't have to put up with that anymore when I trade for a 2014. : (

Evolv0 02-04-2014 12:07 PM

Re: Hemi sounds like diesel when cold
 
How long are you letting the truck warm up before you drive it? since its winter here where I am, I give the truck 10 min to warm up so by that time I don't hear any ticking or slapping. but yes if I am standing right next to it when I first start it up, I hear it also.

But like I said, I don't drive it until that noise goes away.

jp467 02-04-2014 11:56 PM

Re: Hemi sounds like diesel when cold
 
Quote:

Originally Posted by Evolv0 (Post 970403)
How long are you letting the truck warm up before you drive it? since its winter here where I am, I give the truck 10 min to warm up so by that time I don't hear any ticking or slapping. but yes if I am standing right next to it when I first start it up, I hear it also.

But like I said, I don't drive it until that noise goes away.


I let it run for about 1 to 2 minutes. I don't really hear it till I put it in gear then I can hear what sounds like piston slap but really only until I am fully backed out of the garage then it seems to start to go away.

Bikemanx2 02-04-2014 11:59 PM

Im Pretty sure it's piston slap. I have owned 3 gen 3 hemis and they all do it.

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mcclaindave 02-05-2014 11:32 AM

Re: Hemi sounds like diesel when cold
 
Well I am little relieved that someone else is hearing this also. I thought there was something wrong. It doesn't often get too cold in Dallas so needless to say I never noticed it before.

WK2OverlandII 02-05-2014 11:40 AM

Re: Hemi sounds like diesel when cold
 
Quote:

Originally Posted by jp467 (Post 970185)
I think this is probably normal but I thought I would post to see what others think. I have noticed with the cold weather when backing out of my garage the hemi kind of sounds like a diesel for a few minutes until it warms up. I notice it as soon as I put it in reverse and the walls in the garage of course make it seem louder. Sounds almost like a rods knock. I did a little searching on the internet and it seems kind of common some posted its because of the short skirt on the pistons on these. Just wondering what others thought.

Try some Lucas Oil treatment...it will stick to the pistons and stay up at the top of the engine and it will help reduce the noise and wear during start-ups.
Lucas Heavy Duty Oil Stabilizer : Lucas Oil

Huskercory 02-05-2014 11:52 AM

I would be curious to turn off the MDS to see if that is causing the noise. Not sure if this can be done outside of having a programmer though.

From what I understand, the engine goes into 4 cylinder mode by turning off the injectors and also shutting off the oil to the lifters of those cylinders. This allows the lifters to collapse and then not open those valves. Could it be these intentionally collapsed lifters that are causing the noise? Is the MDS active at idle?

Bikemanx2 02-05-2014 11:59 AM

Mds had nothing to do with it. These engines won't activate mds at an idle or when less than normal operating temperature. Plus my 05 Magnum didn't have Mds after the cam and lifter swap but it still made the noise.

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Huskercory 02-05-2014 12:05 PM

Quote:

Originally Posted by Bikemanx2 (Post 970884)
Mds had nothing to do with it. These engines won't activate mds at an idle or when less than normal operating temperature. Plus my 05 Magnum didn't have Mds after the cam and lifter swap but it still made the noise.

Sent from my SCH-I545 using Tapatalk

Any luck quieting it down at all - or have you tried? I'm already running synthetic oil and a good filter. Time to try an oil additive?

rubicontrail.net 02-05-2014 01:49 PM

Re: Hemi sounds like diesel when cold
 
This is a normal "cold" HEMI sound. My 2007 Commander's HEMI has done this from day one.


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