Have you actually crawled under the truck and grabbed each heat shield?

 

yes sir I have ...thing is after it starts and runs it doesnt do it anymore , truck has to sit a while ....acts as if it is a tensioner loosing prime but im not sure ! I thought if it were a heat shield it would do it on evey startup but this is only after the truck sits for a while .

 

Heat shield. Crawl underneath when the truck is cool and check all the heat shields. The clamps are known to break.

 

Ill be sure to double check again , thanks

 

Make sure you grab each end of each heat shield. The clamps break, but they still look like they are holding.

 

I use a rubber or plastic mallet to tap on the heat shields to find those that are loose or making noise.

 

I've noticed camshaft follower/hydraulic lash adjusterrattle at startup for a second or two on many OHC vehicles I've owned. As mentioned, it lasts a little longer on cold startup when it has sat for a longer period of time. It makes you cringe when you hear it, but I've learned to accept it. The noisiest one we have is grandma's 03 I35. When it sits for a week it rattles like all hell for 8-10 seconds.

In contrast, my son's 283,000 mile 2003 Silverado 4.3 OHV with over 10,000 hours of run time starts right up without any similar sound whatsoever.

Or...yeah...heat shields.

 

I have the same thing, everyday, the first time I start my truck, as I think many others do as well. From what I remember reading a while ago, it’s normal. Look up “start up rattle” or something like that, I promise there’s a few threads on what sounds like the exact noise you are describing.

 

I’m on my 3rd Nissan now and they have all done it, heat shields on all three. No worries, I put a few clamps on the pathfinder ant took care of it. As said above.. you can tap on the exhaust pipe around the clamps and it will cause them to rattle so you can determine which ones.

 

Appreciate all the replies guys but if it were a heat shield shouldnt it rattle on every startup ? After the initial startup , it doesnt do it again ! Am I missing something ? Will heat shields act this way after the exhaust is warm ? Thanks

 

Mine doesn’t always do it, mainly on cold start ups in the morning or if it has sit for a long enough period of time. I think it’s combination of cold exhaust and high/hard rev at start up, I hate how they have such high rev. I’ve always thought this to be bad for a cold motor but experts see different. If you have someone to start your truck while you are down low to listen., you might be able to determine the sound better, usually gone in seconds.