I'm in the midst of a long road trip (Michigan to California and back) in a 1990 5.0 Mustang GT. The car was fully serviced prior to departure and is very low mileage for the year (19k when I started). About a day into the trip I noticed that the oil pressure was lower than I remembered (hovering halfway between the median mark and the first quarter mark) and was fluctuating slightly.
As the trip has progressed the needle has sunk lower, so that now its hovering between the first quarter and the minimum normal mark. I should say that this is its normal position, after a long run. It can fluctuate considerably during running. If I put the clutch in and rev the engine slightly the needle raises up above the median mark and under heavy load at lower revs the need can drop to just above the minimum mark.
I've not had any warning lights come on at all, but I'm just concerned that the pressure seems to be getting inexorably lower. Unfortunately I don't know what oil the shop used during the service as it was done whilst I was abroad, however I was wondering if the shop used 5W30 since it was in Michigan and we obviously get cold winters. If that was the case, is it possible that the high heat conditions I've experienced (Wyoming, Utah and Nevada were all in the 100's I'm told) are too much for the oil, causing it to slowly break down and the pressure to drop ?
I've got a three day break now that I've arrived in CA, and I was planning on having the oil changed as a precautionary measure. Is there anything else that I should be looking at (or rather getting someone who knows what they are doing to look at) or am I perhaps worrying over nothing ?
Ta Muchly for any help offered.
As the trip has progressed the needle has sunk lower, so that now its hovering between the first quarter and the minimum normal mark. I should say that this is its normal position, after a long run. It can fluctuate considerably during running. If I put the clutch in and rev the engine slightly the needle raises up above the median mark and under heavy load at lower revs the need can drop to just above the minimum mark.
I've not had any warning lights come on at all, but I'm just concerned that the pressure seems to be getting inexorably lower. Unfortunately I don't know what oil the shop used during the service as it was done whilst I was abroad, however I was wondering if the shop used 5W30 since it was in Michigan and we obviously get cold winters. If that was the case, is it possible that the high heat conditions I've experienced (Wyoming, Utah and Nevada were all in the 100's I'm told) are too much for the oil, causing it to slowly break down and the pressure to drop ?
I've got a three day break now that I've arrived in CA, and I was planning on having the oil changed as a precautionary measure. Is there anything else that I should be looking at (or rather getting someone who knows what they are doing to look at) or am I perhaps worrying over nothing ?
Ta Muchly for any help offered.
