I bought a new Duramax and I have not been driving the Ford for 6-7 days in a row. On the initial start after sitting there is a pretty nice thud from something on initial startup. It sounds like it coming from underneath/engine bay.

Any ideas? I dont think there it a problem, just wondering.

 

I started a thread about this a week or so ago... It has been happening to my truck also after I let it sit a few days. No one had any thoughts about it though

But I really don't think anything is wrong...but it did not do it during the winter when it sat for a few days at a time, just started after it got hot.

 

Ive started it a couple times since today and it was smooth as glass...weird

 

Maybe the fan clutch?

 

Well mine only does it on the first initial start up and after that it runs fine the rest of the day/1-2 days. But after about 3 days of sitting it will have a thud again.

 

why did you buy a duramax? lol

 

because it has 472hp and 960 ft lbs on torque on the dyno. have my goodies i added to it.

I have had several diesel trucks and i love em.

 

try turning off your AC compressor. there is an old TSB about the problem- too much oil drains back into the compressor, due to its low location

 

Mine is always off when I shutdown.