I have a 1993 Trooper L (3.2l sohc) with over 200,000km. When I bought it I heard a lifter or tappet noise. As it turns out heavy oil is bad for the light aluminium engine. (oil that is 10w30 or higher) The manufacturer requires 5w30 due to the fact that it increases fuel efficiency, but they also claim it is the lightness of aluminium engines that require it.

10w30 seems to immediately cause tappet noise especially if the oil hasn't been changed regularly in past history (5,000 - 10,000km).

5w30 also needs to be changed more frequently because it breaks down much quicker than heavy oil. Therefore you can get build up quicker from not changing the oil frequently enough and you get valve tappet noises.

(Apparently most shop mechanics recommended to me using heavy oil, but this is counter productive and wrong)

What compounds the problem is that this engine is a relatively hard working engine (overhead cam high revs) and therefore produces more heat. Previous trucks I've had, had large oil reservoirs thereby increasing a cooling effect and decreasing heat and were pushrod type engines (lower revs cooler operating temp)

So be forewarned as 5w30 oil starts to turn into tar or varnish from engine heat and gums up the valve tappets causing the noise. This is bad if you let it go too long as you can end up snapping valves, heads...

Solution: Save yourself a few thousand bucks by getting an oil change immediately to 5w30 (a high detergent one) and dumping some oil additive detergent for cleaning out oil buildup. Then make sure you change your oil more frequently. After a couple of weeks the noise goes away. If it doesn't go away then you need to have it looked at as you've let occur too long.

I feel it's a conspiracy between the manufacturers, the EPA, and Mr. Lube!

Regards,

A Millbank (zhikr@hotmail.com)