I have a 1997 Pajero, 3.5L V6 injected engine. It has over 200,000 K's on it and burns a fair bit of oil.
There is also a noise similar to a knock or pink but does'nt seem as loud, more of a (tinkle) than a knock...
I can manage to minimise this by using 98 octane fuel, but very expensive as this is a very thirsty engine at the best of times.
I guess that this problem is also having an adverse effect on fuel economy too. Is there any possible remedy that does'nt require major surgery?

Dean

 

Hi Dean.

Hmmm...you could start by trying some engine conditioner that gets dumped into the engine oil. Just go into any automotive parts store and ask what brand they recommend.

Good luck.

Newbie Normogg

 

Again, good advice from the noobie.

What you're experiencing could be the result of worn lifters. Very common in Mitsubishi's, especially high mileage.

An oil additive could provide a cheap solution, but there is no harm running it like that.

The only other 'knock' you may experience is one that leads to engine failure.

 

A second opinion here. It might be caused by your timing being too far advanced, wrong spark plug temp range or carbon build-up in your cylinders causing early detonation. See if your ECU is giving you any error codes. If you can easily pull a plug and check its condition, do so. A treatment like SeaFoam as already stated poured directly into the intake plenum through the disconnected brake booster hose (make sure the engine is warm and do this slowly or the engine will die on you) can clean out any built-up carbon on your intake side, if you determine that that's what's needed. It will smoke quite a lot as you do this, but will burn off soon.

If it is your hydraulic valve lifters, maybe a cleaning is worth a shot. I added some SeaFoam to my oil and drove for about 50 miles. I noticed a marked improvement in the quieting of the lifters (my beast is at 176,880 miles). Then, I refreshed the oil, replacing a quart of oil with a quart of Marvel Mystery Oil to keep deposits from refouling the valves and pistons. Some swear at it; I swear by it.

If it's a mechanical noise you're hearing, it could be the beginnings of major trouble, like a main bearing. Hope for your sake that it's not that. Since you say higher octane fuel effects your symptoms, there's a good chance that it might well be an easier-treated and less expensive valve-related, carbon or spark plug problem.

 

If your engine is the GDI I was told by my Workshop here in NZ that as the fuel is injected directly into the cylinders you can get carbon build up. This was affecting my Chariot V6 3.0 litre at 100000k's and after they worked on it. It is now going better than ever, even improved fuel consumption.