deckerfl

Hi there,
2008 GL320 CDI with 130K miles.
I just changed my fuel and air filters and ran the engine with the plastic cover off and heard an additional noise on top of the usual diesel noise.
Seems to come from the top front of the engine near the timing chain and vacuum pump.
Here's a video
In the video it gets alot louder and different when I remove the oil filler cap

I'm reading alot about timing chain issues on the Bluetech models but not much in this area for the CDIs

Thanks for any help.
Dan

deckerfl

I guess I want to avoid this if possible. From another GL320 CDI Owner with higher mileage...

https://mbworld.org/forums/gl-class-...000-miles.html

"The UGLY! At about 185,000 miles the entire right hand valve train self destructed, save the valves themselves. The vacuum pump, timing belt, camshaft, assorted bearings, all trash. The damage was so complete that it was impossible to tell what failed initially. There is no replacement valve head assembly from MB, not new, not rebuilt. Nothing. It was necessary to catalog every part and order every piece and build it from scratch. This cost, oh, roughly the replacement value of the car at that time. Any sane, sensible person would have dropped in a salvage engine. I am neither, I guess."


Thanks,
Dan

SilverArrow_AMG

I wonder about the same issues. I know its prevalent on the 2009 and up models but I haven't heard any issues with the CDIs. With that said, It does sound like your particular vehicle does have a timing chain rattle.

If you're handy a member did post a DIY guide on replacing his stretched timing chain. Best of luck and please keep us updated.

deckerfl

Thanks Silver Arrow,
I saw that DIY. Very detailed. It's a little beyond what I'm comfortable with and don't really have time for unscheduled work like that. I have done a VW timing belt on an inline 4 TDI, but this is a chain, and a V6. I brought it into a good indy MB specific shop. I'll keep you posted.
Thanks,
Dan

deckerfl

Indy Shop reports that they heard the sound and tried removing the Serpentine belt, and the sound went away. They are going to replace the belt and the belt tensioner and AC pulley that were worn. $1100. Hoping that fixes the issue. Glad it wasn't timing chain as that would've been much more expensive.
Dan

Racin_fool

one of the signs of a worn/stretched timing chain is a cold start rattle for about 2-3 seconds.. There is also a good chance that if the chain stretch is causing the noise on a cold start, that the check engine light will also come on.

deckerfl

All fixed... the shop replaced the serpentine belt, both idler pulleys, Belt tensioner, and the AC_Compressor Pulley. He then recommended changing the water pump while he was in there, so he did that as well and the thermostat. In changing the water pump, a fuel return line got broken and that then also needed replacing. If I weren't in a time crunch with a road trip coming up, I might have tried this myself.
Useful tidbit here if removing the serpentine belt to narrow down if it was timing chain or serpentine belt.

Thanks,

Dan