One of my CRDs purrs louder than the other. Why?

andymoss · **Posted:** Sun Dec 20, 2015 1:39 pm

I have recently bought two 2006 CRD Libertys. Both were broken. One (Tan) broke timing beld and got 8 rockers. I put 16 new ones and a timing kit on it. Runs perfect. The other (Green) had rockers that had failed but not from timing belt. 16 more and another timing kit and that one is fixed too. I have never been around the CRD before now so I am not sure how they are supposed to sound. The one with broken timing is quite a bit louder than the other. What I mean is the normal diesel sound (purr) is louder in the tan one. Like the difference in older duramax and newer ones. They both run the same. Only difference is egr delete in the green one. Both have around 130k miles. What should I be looking into or should I just ignore it? Thanks, Andy

Mountainman · **Posted:** Sun Dec 20, 2015 1:59 pm

probably air in fuel. The fuel heads leak, they sell upgraded ones, and the line that sucks the fuel from the tank has a quick connect that can leak also. An 18" piece of diesel grade fuel line and two hose clamps solves this. Most of us also add a lift pump, in tank (expensive), or inline $40.

Try pumping the primer bulb while it's running and see if that gets rid of the sound, a metallic clack I'm guessing? If so, a new fuel head would probably cure it.

flash7210 · **Posted:** Sun Dec 20, 2015 2:19 pm

Did you have any of the valves checked to see if they were bent?

Louder engine noise could be exhaust leaks at the manifold or turbo.
Could also be improperly sealed injectors. Did you replace the copper crush washers and torque the injectors properly?

Mountainman · **Posted:** Sun Dec 20, 2015 2:37 pm

Good points, put a large screwdriver or whatever you have to your ear and hunt around on the engine to try and discern where the sound is coming from. An exhaust leak should be easy to locate with a long enough apparatus. Valves should be louder on one cylinder vs another. Air makes a metallic clack, and I've found it to sound more like it's in the front of the engine (maybe it forces the majority of the air to injector #1), might sound awfully similar to a damaged valve

A mechanics stethoscope would be better and probably tell you a lot more. I need to get one actually!

andymoss · **Posted:** Sun Dec 20, 2015 4:02 pm

Thanks. I have a stethoscope and I will check for air. The previous owner replaced the fuel head trying to get it running after slipped timing. Ill post what I find. I did not replace copper washers at injectors. I will plan on that soon. Any other advise is appreciated. Thanks again.

jws84_02 · **Posted:** Mon Dec 21, 2015 9:53 am

Call me crazy but I think everyone of these sounds a little bit different from one another. If it was first initial start up I would guess it's just air in fuel rail and will eventually purge out. I also think the ones with tunes are s little quieter than stock ones.

fratichelli · **Posted:** Mon Dec 21, 2015 10:14 am

Other than a GDE Tune, are there other things that might make the engine a little quieter? From what I have read on here the muffler has little to do with the engine noise, straight pipe, flowmaster or OEM the exhaust noise is not the issue - its the clatter from the engine.

xhizzous · **Posted:** Mon Dec 21, 2015 10:32 am

I will second the tune vs stock noise difference.

My 05 with Hot tune vs my 06 with stock, even with the 05 top engine insulation removed the 06 with insulation is noticeably louder at idle.

One of my CRDs purrs louder than the other. Why?

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