I hear rattling coming from the valve covers?

[stewartdrums]

I have a 90 Q45. I hear rattling from time to time comming from the valve covers. I am wondering if I need to change the timming chain guides or is it the chain itself and how do you tell the difference? Thanks

[Q451990]

In a word, yes. If the guides haven't been replaced and you're hearing a noise you're very lucky. Most guide failures don't give a warning, unless you call driving one minute and coasting to a stop the next a warning.

Guide noise has always been described as a "fluttering" sound from the front of the engine (especially at startup). BUT this comment shouldn't be taken as "wait for the noise..."

Heath

[DAEDALUS]

Is it only at startup, or do you hear it when the car's warmed up? How many miles on the car? Valvetrain rattle sometimes happens without enough oil. Does the engine run smoothly, or does it seem a bit out of balance?

[911/Q45]

Could be normal injector clatter, do you hear it just at idle?

[landtodd]

Whew! Sounds like enough uncertainty to park it until you can open it up (or drive gently and directly to whoever is going to do it). You were going to have the guides done later anyway, right?

Agreed about not waiting for some particular noise -- bitter experience within this group suggests that the chain guides give way with no particular warning noise, often on gentle deceleration -- ask Fred. An unusual sound is pretty good cause to open it up, since you need to anyway. That is, if you like the car and don't mind "over investing*"

*"over investing" -- mental trick people play on themselves when they want their current wonderful car to die so they can go into steep debt for something different that will make their current maintenance expense look like pennies to the dollar.

[reggiegsd]

Do a search on "Hydraulic Lifters" or "Tappets". See if that thread describes the noise you hear.