Engine rattle - advice please.

Technical advice Q&A
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JerryL770
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#1 Engine rattle - advice please.

Post by JerryL770 » Tue Jul 29, 2025 7:26 pm

My engine has developed a rattle which is worse when cold but has gotten more audible all the time recently. It is particularly audible when driving beside buildings etc., when the sound is reflected back. It seems to disappear when accelerating but that may just be my hearing.

When cold yesterday, I started the engine and using a big screwdriver pressed against the water pump, ear on the handle and tweeked the throttle, a definite banging could be heard.

I'm suspecting this could be to do with the timing chain tensioner(s).

if so, what is involved with getting in to replace it/them?

Advice appreciated before I take it to get the work done, as likely I won't do it myself. Thanks
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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Gfhug
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#2 Re: Engine rattle - advice please.

Post by Gfhug » Wed Jul 30, 2025 9:27 am

Jerry, I’ve not worked on that part of the engine, but a search on here for “tensioner” brought up 380 results. You’ve probably already searched, but could one of those describe the work involved to help you decide if you’ve got a big enough hammer :bigrin: to do it yourself?

Sorry, I can’t be more helpful and good luck

Geoff
S2 FHC Light Blue
S2 OTS LHD - RHD full restoration

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mgcjag
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#3 Re: Engine rattle - advice please.

Post by mgcjag » Wed Jul 30, 2025 9:38 am

You have 2 chains and 2 tensioners..check and adjust top tensioner...its simple..... lower tensioner..see service manual section on chain tensioner and how to replace it....Steve....
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

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#4 Re: Engine rattle - advice please.

Post by JerryL770 » Mon Aug 04, 2025 9:08 am

Thanks Guys. And yes, I have done a search which is not very conclusive, various possibilities.

So, I can possibly check the top chain tensioner myself but the service manual is not very helpful with respect to checking the lower tensioner with the engine in the car. Big question is: does that have to be an engine out job?
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT - now gone :sad:

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mgcjag
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#5 Re: Engine rattle - advice please.

Post by mgcjag » Mon Aug 04, 2025 9:22 am

The service manual details how to get to the lower tensioner.....I could explain it but its there in black and white....Steve
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

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