2004 WJ 4.0 158,000 mi. We have had some cold weather the last couple days and when I started my Jeep, the oil pressure gauge remained at zero and the check gauges light came on. Shut it off and checked the oil, level looks fine. Looked for visible leaks and saw none. Started it up again and the gauge showed normal pressure and I went on my merry way. Engine runs smooth, no knocking, smoking, or high temps. Was fine for a while but It has happened a couple more times since then. I am hoping it is the oil pressure sensor as I have had those fail before on some XJs I have owned. This is my first WJ. My garage is packed and It is to cold outside right now for me to put a mechanical pressure gauge on it to accurately check pressure. My question for the experts on the forum is whether or not these are symptoms of a bad sensor or indicative of something more serious. Is there a danger driving it with the check gauges light on when it seems to be running perfectly. Would I definitely be experiencing issues if there was indeed no oil pressure? Is there another way to check if there is any pressure other than installing a mechanical gauge? I love this truck and don't want to mess it up. I am hoping for an easy fix. Thanks in advance for any helpful comments.

 

It should be a 15 min job to replace the sensor. High temp, horrible clattering ,ticking lifters all highlight low oil pressure. Not having a 2 nd method to verify, you can only make a guess based on the above. Oil pumps don't cycle from 0 to perfect, bad sensors do. You should be able to tell (hear) the difference between low and normal oil pressure in the first 2 seconds of startup every time you start the engine in the morning or after sitting an hour or two...might not help at highway speed until too late. Even if you install a mech gauge, its usually in the engine bay and you would have to stop anyway...fix sensor

 

[QUOTE=bluejeep2001;3710628]It should be a 15 min job to replace the sensor. High temp, horrible clattering ,ticking lifters all highlight low oil pressure. Not having a 2 nd method to verify, you can only make a guess based on the above. Oil pumps don't cycle from 0 to perfect, bad sensors do. You should be able to tell (hear) the difference between low and normal oil pressure in the first 2 seconds of startup every time you start the engine in the morning or after sitting an hour or two...might not help at highway speed until too late. Even if you install a mech gauge, its usually in the engine bay and you would have to stop anyway...fix sensor[/QUOTE

Thanks bluejeep2001. That makes perfect sense and I appreciate the reply.