Chrysler Repair: low oil pressure/valve train noise, tappet noise, low oil pressure

Question
Hello,

I just put a timing belt on a 97 concorde 3.5l with about 170000 miles on it. The old timing belt had about a ten inch space where the teeth had been sheared off. I followed the guidlines in my service manual when replacing the belt. After driving the vehicle about ten miles, I was pulling a steep hill. The car suddenly began running poorly and the check engine light came on. At low rpms the oil light came on. I immediately stopped and added about 3/4 of a quart of 15 40 oil filling the pan to the full mark. The oil pressure still runs low and there is a lot of noise from the valve train. What could cause this, and what should I do to restore oil pressure?

Answer
Hi Don,
You might want to see what the pressure actually is with a gauge in place of the oil pressure sensor unit to be sure that it is mainly a pressure problem before you do anything beyond inspecting the belt. At idle the pressure should be 5 psi or more, and at 3,000 rpm it should be 25-105 psi. It is located next to the oil filter.  If it is lower than the spec:
It could be the oil pump is worn or the oil pressure relif valve has gone weak. If the pressure were low that would explain the valve train noise because the lifters have to be pressurized or you get tappet noise. Because the timing belt had been recenty replaced, it might be that something is wrong with the timing as far as the poor running that also occured. But the oil pump is driven by the crankshaft so that shouldn't be affected by the belt question.
My manual shows that the relief valve can be serviced by removing the oil pan only. But to service the pump you have to essentially go through the process that was involved in the timing belt replacement and also do the pan removal/pick-up tube and crank sprocket to get the pump off. I guess you might start with the pressure measurement and a belt inspection. If the pressure is low then remove the pan and change the relief valve, and if that doesn't restore the pressure then you have to probably remove and replace the oil pump.
Roland
PS Sorry for the delay but I just found your question in the 'pool' to which it had been referred by Kevin, the other 'expert'.