the great oil debate???

[1badnevergo]

Ok I have a 92 Mazda Navajo 5 spd 4.0 V6 it has 195,000 on it 2 months ago I got an oil change and switched to full synthetic 10w40 due to my valves rattling with the old 30 weight in it I still have valve chatter on start ups and hot weather passing speeds Im wondering if I can switch to a synthetic 20w50 also if it helps I got the truck from my brother and he never changed the oil or plugs in the 2 years he had the vehicle thanks!!!

 

[Jon94]

If you have valve clatter, it means some of your valvetrain parts are worn out. Oil will not fix worn parts. The only fix is to replace the parts. Thicker oil can mask noises like this, but it doesn't make the problem go away.

It's like a doctor telling you you have a disease, but you just cover your ears saying "La la la I can't hear you! La la la!!" Covering up sounds doesn't make problems disappear.

A 50 weight oil is too thick for this engine IMO. A 40 weight is even a little thicker than I'd use, although it won't hurt anything. I would stick with a 30 weight and either just live with the noise, or replace the worn out parts.

 

[Verno]

Depends on how long you plan to drive it. Since you know it did not get proper maintenance in the life "before you," you can expect major expenses in "corrective" maintenance now. You can try some SLICK 50 or other brand oil treatment, but with 195,000 miles and no oil changes = major wear on moving parts. You can rebuild the motor, or replace the vehicle but you're gonna pay for his mistakes sooner or later.

 

[1badnevergo]

My bad guys I failed to mention that the valve chatter is also after a rebuild I was working as a mechanic and some old schools as they liked to be called recommended it when I got the truck. I replaced the rings and went up from there new heads and all. The motor only has to make it one more season before I rebuild it from scratch as I plan on stroking it. Also it was recomended to Me that I run 10w40 and a qt of Lucas and that's what Ive done since Ive had it. I also found that the only time I am gettin chatter is on high speed passing on hot days the cold start chatter I was hearing was actually my pa speaker against the radiator support thanks for the advice

 

[jakprince]

Sounds like spark knock to me instead of valve chatter.