DmaxProf
07-30-2005, 14:35
Just returned from a 3000 mile round trip across Missouri, Kansas, and half of Colorado. I was pulling a 12K 5th wheel with a lot of frontal area (I was pushing a lot of air). I noticed that going down the interstate bucking about a 30 mph headwind and climbing various inclines that my oil pressure was indicating about 45-52 psi. The rpm was about 1800-1900, the speed was about 55 mph, and the EGT gauge was climbing to about 1200-1250. At that point, I locked out the OD which caused the rpm to rise to about 2500 or so, the EGT to drop back to around 1000-1100, and the oil pressure rose to about 60 psi. Whenever I locked out the OD, the oil pressure would rise to about 60 psi and stay there until I re-engaged the overdrive, at which point it would drop back to about 45-52 psi (the gauge is kind of hard to read).
Subsequently, I noticed that whenever the engine was working the hardest, i.e., EGT and boost increasing to produce power to climb a grade or to fight a headwind, that the oil pressure tended to decrease to about 45-52 psi. It seems to me that my truck used to hold about 60 psi no matter what I did or what demands were made on the engine. But maybe I wasn't paying close enough attention. It scared the daylights out of me when I first noticed the oil pressure reading what appeard to be abnormally low.
Once I arrived at Colorado I noticed that the oil pressure at idle was about 15 psi. I don't think I ever saw that low an oil pressure reading before. I took the truck to a dealer who informed that everything was in specs and that there was no problem with the oil pressure gauge, the sensor, or the oil pressure system.
By the way, the truck did not use any oil and the oil only had about 1000 miles of use since its last change. I am using the OEM oil filter which also was replaced at the last oil change. When the engine was started and was cold, the oil pressure reading was around 60 psi. There was no decrease in the reading unless the engine was really warm and under load.
The truck is stock except for an EGT gauge, a boost gauge, and an Edge EZ set on level 2. I monitored EGT temps to make sure that I did not exceed 1250 while towing. The truck is running great and pulled like a champ over some 6% grades, so there has been no deteriation in performance. For one stretch of the trip I unplugged the EZ to see if running stock would make any difference in the oil pressure readings. It didn't. I saw the same readings.
Has anyone else had a similar experience? Does this seem like normal operating behavior? Does the oil pressure typically decrease when the engine is under heavy load? Do I have a problem, or should I just relax since the truck is running great other than the oil pressure readings?
Subsequently, I noticed that whenever the engine was working the hardest, i.e., EGT and boost increasing to produce power to climb a grade or to fight a headwind, that the oil pressure tended to decrease to about 45-52 psi. It seems to me that my truck used to hold about 60 psi no matter what I did or what demands were made on the engine. But maybe I wasn't paying close enough attention. It scared the daylights out of me when I first noticed the oil pressure reading what appeard to be abnormally low.
Once I arrived at Colorado I noticed that the oil pressure at idle was about 15 psi. I don't think I ever saw that low an oil pressure reading before. I took the truck to a dealer who informed that everything was in specs and that there was no problem with the oil pressure gauge, the sensor, or the oil pressure system.
By the way, the truck did not use any oil and the oil only had about 1000 miles of use since its last change. I am using the OEM oil filter which also was replaced at the last oil change. When the engine was started and was cold, the oil pressure reading was around 60 psi. There was no decrease in the reading unless the engine was really warm and under load.
The truck is stock except for an EGT gauge, a boost gauge, and an Edge EZ set on level 2. I monitored EGT temps to make sure that I did not exceed 1250 while towing. The truck is running great and pulled like a champ over some 6% grades, so there has been no deteriation in performance. For one stretch of the trip I unplugged the EZ to see if running stock would make any difference in the oil pressure readings. It didn't. I saw the same readings.
Has anyone else had a similar experience? Does this seem like normal operating behavior? Does the oil pressure typically decrease when the engine is under heavy load? Do I have a problem, or should I just relax since the truck is running great other than the oil pressure readings?