Question about engine buring oil

[Bullet]

My truck, a 1994 dodge dakoda with a V6 automatic, on occasionally (once or twice a week) has been blowing a puff of smoke out at start up for the last three years. It has about 135,000 miles and recently, when at idle (in traffic)for about 5-10 minutes will burn oil really bad for the next 3/4 mile then clears up. Last month it used two quarts of oil. The truck runs fine. If it doesn't idle for extended times no oil is burned. While discussing this with my brother he mentioned its probably pulling oil through the valve seals because at an idle an engine draws the most vacumm.

Today, I pull the plugs (bosch palt) that have been in for about 100,000 miles and show zero evidence of oil buring. A compression check all clyinders are between 140-145 psi, don't know what a new engine would be, but the service manaul says a min of 100.

Today, I changed the valve seals on one side until the rain came so the other side will have to wait until the weekend.

My question is, should I start using a oil for high milage engines or thicker oil such as 20w50? If always used 5w30 or 10w30. thanks

 

[Drew99GT]

Your brothers diagnosis is spot on; valve seals. It may be a long shot, but a highly regarded product on this board, Auto-RX, may help. It cleans sludge and varnish. Was there any noticable sludge when you had the valve cover off? If not, then I doubt Auto-RX would help. I'd maybe go up 1 notch in viscosity to a 15w40 such as Delo or Delvac 1300. Your in New Orleans, so cold temps are no factor as far as oil thickness goes. With valve seals I think, once they get cracked and old, you just got to replace them. Several people have had great luck with the High Mileage oils slowing oil consumption, even from bad valve seals. That's worth a try too.