I agree about the timing chain tensioner and guide rails.


After 25 years, almost certainly the guide rails won't be white as when new - nor uncracked.


I'd bet you will find them root beer brown and brittle covered with hairline cracks, and about to crumble;


and if it disintegrates, the timing chain will slip, pistoncs crash into valves and that 53k mile motor will be toast.


Definately time for that timing change refresh. --- Worth it too for a car in such mint condition.

Consider it routine maintenance, if you have to.

__________________
1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...

1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)