I have a 2000 Chevy Silverado 4.8 engine. When I pull my RV my oil pressure drops to zero after about 40 miles?
When not pulling anything the oil pressure runs 50
to 60. The engine was running about 3000 rpm
uphill and engine temp is 210 pressure starts
dropping slowly when it gets under 40 it starts
dropping fast. Take the load off engine and let
cool down oil pressure goes back up.
first try and change the oil/filter..go up 10 in weight or try 20-50....!
kelly is right you are probably running a 5w30 or a 10w30 oil and it is not enough depending on the mileage of the motor. like kelly said I would got up 10 in weight and if you are already running 20w50 your pump is failing on you and might need to be replaced. when ever you change your oil I would use lucas oil additive. and if you are using 20w50 oil and your going to change pumps I reccomend a hi volume pump.
An oil pump is the most common failure. But be aware that sometimes a flaw in the engine block can also cause this same problem, the pressure will be fine under normal everyday driving but when a higher loads than normal are meet the flaw opens up due to increased heat and the oil pressure drops. So if the problem is still there after you replaced the oil pump then you know what is next.
I agree with the oil change and the pump and would go a step or two further. How often are you pulling something? If it's a lot, consider adding a oil cooler. The other problem it could be is that you have some burned main baring's. Knowing how many miles on the motor and the size of the rig you're pulling can help us with your problem diagnosis.
The engine has 187000 miles on it, I usually run 10w30 in it the last time I got it changed the oil place put 5w30 in it I had the same Problem went and changed the oil myself to 10w30 and had the oil changed after about 800 miles to 10w40 high mileage. I pull a 24 foot bumper pull RV. I do not pull it much maby 2 or three times a year.
Check and maybe replace your oil sensor. Those have been known to go bad after a while. Very common problem. Gives strange readings. Other hat adding heavier oil, it is the next cheapest way to check and or replace. There are external oil coolers that can be added to tow vehicles, both for the engine and transmission. Look into those. I would recommend changing to a 20-50 oil in the warm months, and 10-40 for winter.
I agree with the sensor replacement; I have had that happen in one of my vehicles before. Have you ever run a compression check on your motor? With 187K on it, it should be ok, but you never know; a compression check is a very inexpensive check to tell you the internal health of your motor.
When I pulled my boat to the lake, I always ran 30W in the summer and changed in the winter to 10W40. Old engines don't have the tight tolerances they once use to. That's a lot miles and it wont hold new engine pressures, they always drop off when it gets hot.
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