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My 1995 V6 Mitsubishi Diamante saloon (odometer is showing 170K) has developed excessive tappet noise.

One mechanic I spoke to said to use only synthetic oil while another recommended a regular type oil.

Your opinion please.

Michael

From the "Ask Jack" archives - 3 December 2009

I strongly suspect the noise is the hydraulic valve lifters which tend to suffer from grit and gunge build up over a long period of time.

Unless you address this issue properly, which means replacing all the hydraulic lifters, anything else you do will highly likely be very temporary.

I have heard a product called PROMA MBL8 is the one of the best additives to try in an effort to reduce / eliminate the rattles like this albeit short term. It is simply added to the engine oil and is only available from independant distributors.

These distributors can be obtained from the website www.pro-masystems.co.nz.

Using a synthetic oil or changing the grade will achieve very little at this stage in my opinion.

If the lifters were replaced however, a good quality oil going forward would be very advisable.

Have a 2000 Mitsu Galant SEi and am wondering how much replacement hydraulic valve lifters will cost. Thanks for info - Pammie

We would not be surprised to see an invoice for around $1,000 but that is very much an educated guess.

You need to get an estimate from your preferred repairer as there be other parts that need to be replaced once they have listened to the engine.