Have wondered why when you start the 06 Dodge Cummins sometimes there is a loud clunk,does anyone have or heard of this??Is it normal?
Toy hauler

 

Yep it's normal. Is your AC on when you start it? If so it's your AC compressor. Mine does it too. Scared me at first.

 

Wow unbelievable,thanks for your input.....Thom (TOY HAULER)

 

I agree with t-boe. 3-5 seconds after start up.............BANG!

 

mine does it to, something with the ac.

 

I have fallen into the habit of turning the AC off before I shut down .....and mine hardly ever does it....just thought I would pass that on...may or may not help but it sure seems to on my truck.

 

Agree with 53, since I started shutting Compressor off before shutting truck off, I do not get the clunk any more. But I used to...Man I hated it, was waiting fo rthe compressor to be my next issues..

 

I've gotten a similar clunk that sounds like it's coming from the passenger side of the engine compartment. It doesn't seem to be dependent on having the AC turned on (I 1st noticed the noise about a month ago, when it was still cold here). Sometimes it sounds like a clunk and other times like a grinding noise followed by a clunk. Always within a few seconds of startup.

I'll ask my dealer the next time I stop in, but it's comforting to know that others have the same noise.

 

Mine is on the passenger side too, but i bought the truck in the winter down here and just now starting to leave the ac on. and it clunks almost evertime know.

i thought it only clunked once after being shutdown for an extended period. mine seems to clunk even after being run.

 

dont forget when your defrost is on...... your A/C is on too

 

You guys don't think it's the A/C blend door hitting against the stop?

 

I dont think mine is that... but who knows???

 

I turn mine off now too. The first clunk is pretty loud on mine but even if it sits for 8-10 hours at work there is barely a noticable noise. Mine only clunks loud after it sits overnight. Every start up during the day is a nice and quiet clunk.

 

so are you saying you do or dont get it if you shut the A/c off before you turn the engine off??

 

the sound you are hearing is nothing to worry about . my 04 and 06 both do it. its just your ac compressors clutch kicking in. if you shut the truck off with the ac on or with the heater in the defrost position the compressor is being stopped with pressure still on it. these new compressors are sealed very well and seem to hold pressure for a long time even with the engine off. when you start the truck there is a few second delay and the ac compressors clutch will engage and when it does , because there is already pressure in the system its like you are starting the compresser with a load on it and you hear a "CLUNK" or maybe even a tiny belt chirp. the reason it makes this noise with the defroster on is because in order to keep the ac comressors seals from drying up and internal parts from sticking from lack of use it has been designed into your heat/cooling system that in the winter months your ac compressor cycles on and off in order to keep the compressor lubricated and in good working order. dont sweat it. its normal for this vehicle