Rattling noise...

[SebW20]

A rattley kind of noise has started coming from my engine bay; can only really hear it at tick-over or low revs and doesn't seem to change whether or not the clutch is engaged or in different gears etc.

There doesn't seem to be any other symptoms at the moment. It's hard to track down exactly where the noise is coming from but I think likely culprits are water pump or alternator.

Just wondering if anyone else has had the something similar or knows of a good way to determine or rule out any possibilities?

Cheers

[mr2magic]

Check the heat shields on the firewall.

[aussieGT]

and the engine lid prop rod.

[pbmr2]

Had a rattle for months and never been able to track it down, until yesterday. It was the forward screw on the left inspection panel. Some clown in the past had used sealant around the holes, front screw was stuck slightly short of fully down. Rattle.

Had to trim the screw head flat on 2 sides to get some grips on it as a screwdriver wasn't shifting it without destroying the head.

Not saying yours will be in the same state (never had an issue with inspection panel screws on many mr2s before) but worth checking they are tight.

[rev3gtturbo]

A couple of times I have had weird engine bay rattles over the years and not found anything loose. Turned out to be mechanic leaving a socket on the right side of the block and it being hidden under pipe work.

[abovetherim]

To rule out or confirm the alt all you need to do is remove the alt belt and run the engine, but only for a couple of minutes as the battery will not be charging.
If it isn't the alt check at the nuts and bolts you can find, maybe one of the cam cover bolts is loose as the rubber washers perish.
Other culprits could be one of the injectors getting noisy or the timing belt idler puley or the crank pulley delaminating?

A good way to track down noises is to use a long bar (screwdriver) as a stethoscope touching it to different points on the engine(nothing moving) and putting your ear against the other end.

[SebW20]

Thanks for the replies

I think I can be pretty sure now that it's the water pump; it started to make some new, slightly more concerning, noises along with increasing engine temperature, so that's her off the road for now.

Anyone know of a decent brand water pump to buy? I don't wanna skimp and buy a sh*tty one which will just break again sometime down the line... especially as I'll be dropping the engine to switch it

[pbmr2]

Dropping the engine to change the cambelt and water pump? seems a little extreme.

go with a pump that has a metal impeller, not the plastic ones. unsure of brands.

get a new tensioner when getting a cambelt kit

[Draven]

You don't technically "need" to drop the enjoy for the water pump you can change it in situe, however if you have any other jobs such as clutch etc it is invaluable to drop the engine as it is much easier to work on.

[auzzam]

had a rattling noise recently on mine coming from the cambelt area, turned out to be a loose screw that gave way and dropped in. had the tensioner changed too - so could of potentially been this too