Questions and Answers

Time To Let It Go? Q. Vince, I have a 1 owner 1989 GMC S-15 4WD Jimmy with a 4.3L V-6. It has been extremely reliable over the past 12 years. It has 235,000 miles on it and not including ancillary components, it has had the following engine related repairs:

A new distributor (including shaft) at 180,000 miles. (THAT's IT!)

Here's the rub, last week it developed a new condition. When the engine is cold or running over 1000 rpm such as at any driving speed, the oil pressure is fine (about 40 psi). However, when idling at a stop light or idle speed under 1000 rpm on a hot engine, the oil pressure drops to 5 psi. I am considering an oil pump replacement (about a $400 repair), but am I asking for other problems once this is done? I would hate to replace the oil pump and have that lead to other failures, but then again I hate to give up on the old girl, especially when you consider the price of today's new vehicles!

Is it worth it? Or is it time to just let go?

Thanks,
Scott

A. This is a common condition on very high milage engines. What has happened over time is the engine has worn. Tolerances are larger than a new engine and the bearings are worn. In short, the engine is not "tight" anymore. Replacing the oil pump may bring the oil pressure up somewhat, but to really fix the problem you need to rebuild the engine and get it back to new specs.

A heavier grade oil will bring the pressure up some, in fact you may want to consider using a straight 30 or 40 weight oil. This will be fine for summer driving, but it will make it harder to start in the winter.