I've read all the post about head and valve problems but I think thismay different because it is a new 08with less than 500 miles on it.
When the engine is started cold, there is a loud rattle coming from the engine. I have tried to locate it but it sounds like it's coming from the top of the engine somewhere. It only does it for a moment just when the engine is started then goes away. Has anyone else had this problem?

 

I have 7000 miles on my new '08 3.7L. I have not experienced the problem you describe.

 

Take a look at the intake system, make sure the hose clamps are snug, and check the bolts that hold your intake resonator box on top of the motor (there should be two 10MM bolts to the left side of the resonator box.I am assuming you have the I5, they are not inherently balanced and do make some interesting sounds when cold started. They vibrate a bunch during cold start up strategies programmed in the PCM and ............... just check the intake, it is simple, if not that, double check the oil level.







If I could only type. [&o]

 

^^^^X2

my intake makes a terrible noise when the motors cold.

 

I make terrible noises when I am cold also.

 

My 08 H3 is less than 3 weeks old - 700miles.

Whenaccelerating (cold engine mostly) up to about 30mph,I hear a vibrating noise.....similar to what my old '89 Bronco II used to do......I believe it was the resonator under the vehicle. For me, however, it's no biggie and something I've been used to for a long time......drovethe Bronco for 238,000 miles until it just stopped one day.......had to put her down.

Does anyone know if the H3 has a resonator attached to the catalytic converter or somewhere along the exhaust system?

 

DEALER SAYS:
The timing chain tentioner is actuated by oil pressure. So before the oil pressure comes up on a cold start, the chain slaps.
I don't know if I beleive that.