I am looking to fix two annoying issues with my otherwise happy car:

1. Dash noise - had my mechanic replaced both heater and airconditioning cores. The dash has never been the same since. At idle, the left side of the dash in this RHD car rattles noisily. It used to be the right side that rattles but after I got mu mechanic to have a look at it, he must have tightened something on the right that's caused the left to now become noisy.

I am after some quick tips as to how I should approach fixing this noise issue.

Having read some threads about this from the archive, can someone advice me:

a) Do I need to remove the whole top part of the dash (that connects to the firewall) or would just tightening the four screws from the engine compartment side fix this?

b) What else should I do to quieten the dash?


2. Funny smell of petrol/exhaust at start with the aircon running:

I can't make up my mind if it's petrol that I am smelling or a bit of exhaust. Some passengers think it's petrol.

After the aforementioned heater/aircon core repairs, whenever I start the car with the airconditioning running, there's a funny smell that permeates the cabin. It's especially stronger when the climate control is set to take in fresh air than if set to REC. Either way I still get the smell. If the fan is blowing and the airconditioning is OFF, I don't get the smell.

Also, after the car warms up, I don't usually get that funny smell at all.

Has anyone experienced this? Would the heater/aircon core repair have caused this? I can't seem to figure out how the fumes can be coming in from the engine bay.

Appreciate your thoughts on these issues.

Thanks

Lucast