TIMING CHAIN _ 420 SEL


I have 180,000 miles on my 420 with the original timing chain. I was told that signs of it first going is when the tachometer starts to flucuate at idle. Is this true? So far so good, no flucuation. Car runs like a dream.

Should I change the chain? Or don't fix what ain't broke? Is this expensive to check and / or replace if necessary?



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'89 420 SEL
'90 300 SEL
'68 Olds 88 Convertible
'84 300 SD (sold it)