MDS noise - tech input needed

**Kim Hufty** · 10-02-2008, 11:07 PM

My early 2005 Magnum with 115,000 miles has a lot of MDS noise. When I say a lot of noise it sounds like a loud sewing machine or even an exhaust leak. I have checked for exhaust leaks and even did the EGR deleate to insure what I was hearing was valve train noise. One more test I did to convince myself is when I switch to autostick mode the noise goes away 100% after the lifters pump back up.
The noise starts after the oil comes up to tempature and the MDS has been working for a while. When it kicks from 4 to 8 cyclinder the noise is imediate. It minimizes when it goes back to 4 mode. It's like the lifters that are shutting off during 4 mode are not pumping all the way back up to go into 8 mode after they have been off. It just does'nt stay in 8 mode long enough to get the lifters pumped all the way up.

Is there a history of the MDS lifters going bad after higher miles? This could be an expensive fix pulling the heads.
Is there a possibility the oil solanoids could be bad?
Could the recovery oil pressure be controlled or influenced with the Preditor programming?
Is this noise an indication of total lifter failure to come that could cause some damage?

I would like to get rid of this noise so I'm looking for some knowlagable input.

**MAGUIRE** · 10-02-2008, 11:29 PM

bump.

**fnkychkn** · 10-02-2008, 11:34 PM

SUBJECT:

TECH-TIPS # 49 / 2005 – 2007 LX / WK / XK / HB / DR equipped with a 5.7L HEMI

Engine Multi Displacement Cylinder Deactivation System (MDS) - Rattling Noise During Cylinder

Deactivation
Several reports have been received regarding a rattling noise that ONLY occurs and remains
during cylinder deactivation mode (V4 operation). After a few repair attempts, the root cause was
determined to be a worn crankshaft timing chain gear keyway. Please advise service technicians
of this possible cause of a rattling noise when confronted with a similar customer concern and
advise them that the subject noise is not present during any engine operation other than MDS mode.

**mhigham** · 10-03-2008, 12:21 AM

Originally Posted by fnkychkn

SUBJECT:

TECH-TIPS # 49 / 2005 – 2007 LX / WK / XK / HB / DR equipped with a 5.7L HEMI

Engine Multi Displacement Cylinder Deactivation System (MDS) - Rattling Noise During Cylinder

Deactivation
Several reports have been received regarding a rattling noise that ONLY occurs and remains
during cylinder deactivation mode (V4 operation). After a few repair attempts, the root cause was
determined to be a worn crankshaft timing chain gear keyway. Please advise service technicians
of this possible cause of a rattling noise when confronted with a similar customer concern and
advise them that the subject noise is not present during any engine operation other than MDS mode.

So the fix would be just a new key way? Might as well throw in a new chain too and other parts while you are in there.....

Mike

**Charger4Life** · 10-03-2008, 09:38 AM

FNKY, Kim is stating problem when going from 4 to 8 cylinder, that article describes going into 4 cylinder mode. Right?

I had the same exact problem Kim. When I was going slow down to 20 mph and the 8 cylinders engaged it sounded like there were about 5 cans of spraypaint with balls rattling around. I ended up ditching the MDS lifters and haven't heard the noise since.

**dudeiwin86** · 10-03-2008, 10:30 AM

what cam are you running?
what heads are you running?

sounds like your problem is right there.
and it may be your egr tube sticking into the manifold making all that noise when MDS kicks in

mixed with headers, im not suprised you hear the MDS

if i had to gamble... your cam doesnt sit well with MDS and is messing up the lifters?

**Kim Hufty** · 10-03-2008, 02:13 PM

I have a Sidewinder cam with shaved Franks econo heads. I have invested in the Smith custom length push rods and I have deleated the EGR (no tube going to intake). The Sidewinder is not a real agressive cam but maybe it accelerates durability for the lifters??? I have 30,000 to 35,000 miles after the cam install.
FNKY -Thanks for this TECH TIP!!!! by 4 cylinder mode do you just mean MDS is on or just when 4 cylinders are activated.? My noise is when the MDS is ON and it switches from 8 to 4. When I am running on only 4 cylinders I do not hardly notice the noice.
Today I was in drive and the noise was present so after a while I put it in autostick mode, and after 15 to 20 seconds the noise went away. Then after a few minutes in autostick I put it back in DRIVE and it took 30-45 seconds or so before the noise was back.

**formerice** · 10-03-2008, 03:09 PM

Has anyone put a lot of miles on an aftermarket cam with no problems. I have over 142,000 miles and plan on doing a cam soon, I would feel better if a few folks have had no problems and a lot of miles. If it's only the key getting loose, thats a bit different and less worrying.

**fnkychkn** · 10-03-2008, 09:34 PM

Originally Posted by Kim Hufty

I have a Sidewinder cam with shaved Franks econo heads. I have invested in the Smith custom length push rods and I have deleated the EGR (no tube going to intake). The Sidewinder is not a real agressive cam but maybe it accelerates durability for the lifters??? I have 30,000 to 35,000 miles after the cam install.
FNKY -Thanks for this TECH TIP!!!! by 4 cylinder mode do you just mean MDS is on or just when 4 cylinders are activated.? My noise is when the MDS is ON and it switches from 8 to 4. When I am running on only 4 cylinders I do not hardly notice the noice.
Today I was in drive and the noise was present so after a while I put it in autostick mode, and after 15 to 20 seconds the noise went away. Then after a few minutes in autostick I put it back in DRIVE and it took 30-45 seconds or so before the noise was back.

that tech tip is for noise when running in 4 cylinder mode (MDS active). pretty sure autostick defeats MDS and your engine will stay in 8 cylinder mode. if noise goes away in auto stick and comes back in drive, i'd say it only happens in 4 cylinder mode and i'd be checking that keyway.

**Kim Hufty** · 10-03-2008, 11:20 PM

sounds like good advise
Thanks

**Kim Hufty** · 10-04-2008, 12:43 PM

Fnky - If we go to the trouble to open the front I want to have all the parts I could possibly need before hand. With 115,000 miles I might as well replace some wear prone parts. Other than the chain and lower gear what other parts should I consider getting beforehand?Part #s?

**Hemi31** · 10-07-2008, 10:28 AM

Change the cam gear and thrust plate as well.......the plastic guides wear,and with that mileage swapping out the oil pump would be preventative maintenence.

**fnkychkn** · 10-07-2008, 08:19 PM

Originally Posted by Hemi31

Change the cam gear and thrust plate as well.......the plastic guides wear,and with that mileage swapping out the oil pump would be preventative maintenence.

^^ what he said. ^^
he's got way more hemi experience than i do.