Couple of questions, fuel filter and manifold

[e32lover]

Gday, Im about to service my car again ( You reckon 10,000k's is a good service interval for an 02 nm 3.5 petrol)?

Anyway I decided to do the fuel filter, do you generally replace both of them or just the one that's not in the tank?

Also according to the manual im supposed to check valve clearances at 150k, I do have some tapping but it is really nothing noteworthy, you reckon its worth doing?

Also, my car has the stock manifold, will a visual inspection determine if it is cracked or is there some other means for testing? I tried blocking the exhaust and didn't notice any excessive noise from the manifold, but it is the stock 11 year old manifold and I really want an excuse to add extractors and a new exhaust system. Also apart from rattling is there any means for testing the cat?

Im chasing better fuel economy, currently getting about 450 to a tank, although im running 285/55's, however I didn't notice any difference in economy between the 285's and the stockies.

Thanks for any advice.

[dolphin]

normally just the under bonnet fuel filter needs to be replaced. you can normally tell when the exhaust manifold has a slight crack by the ticking sound that comes out when driving or idleing the car, don,t mistake this ticking sound for faulty valve lifters . when you hear the ticking open up the bonnet and have a good listen also if you notice a dark hairline this can indicate a crack. the valves are hydraulic and not adjustable maybe your refering to the deisel engine which has adjustable tappet / lifters.

[offroaddad]

Just had my NM petrol rebuilt, and have been advised that I should do the oil and filters no less than every 5000, Engine rebuilders don't want to do the servicing so I take that as honest advice. It also works out well for the tire rotation.