I've got one that's noisy. Needs replacing. Can I access this by removing the inlet manifold? Someone told me that I have to take the cylinder head off, is that correct? Thanks for any help.

 

Before you replace it, this is one of the few times I'd recommend an oil additive. It may just be dirty or sticky and the proper additive could possibly free it up. Seafoam is advertised to work for this. I would add it at an oil change, don't throw it into a crankcase full of dirty oil.

 

Thanks for the advice. I've already tried that so need to replace. Just need to make sure about getting to it. Thanks.