4.0 check engine light came on
 

4.0L with 214K miles. The check engine light came on. I noticed the oil pressure being between 10-25psi in highway driving, which is usually 40-50 psi. On slowing down and at stop lights, the pressure was coming down to around 5psi. Check gauges light never comes on. The engine is running smoothly. I had recently changed oil (Castrol Edge synthetic 10w-30) and oil filter (Fram rated at 10K miles).

When I checked the oil level a few times, it was fine. Noticed some smoke coming out of the dipstick pipe when I took out the dipstick to check the level. I do not recall seeing that before. Engine temperature is fine, enough antifreeze in the reservoir.

Couple other things - engine does leak oil (oil drain plug and rear main seal). In winter time ONLY, the oil pressure gauge goes to 0 and check gauges light comes on and that too not every day of winter - it happens randomly. Check gauges light goes away once the weather improves and the oil pressure gauge comes back to 40-50psi.

Best troubleshooting you can do is swap to a quality filter like Napa, Mopar or Wix. And oil too and see if it still happens

Thanks. I will try that solution. I'm going to check the issue with an OBD reader first. I have been using this oil/oil filter combo for the past 5 years with no issues. I switch to 5W in winter.

NEVER trust a Fram.

Are they really that bad? I will replace with Wix, NAPA or Mopar. Also, any recommendations on synthetic oil? Castrol Edge was recommended to me and I have been using that.

This.

You could have been slowly killing your jeep and not know it. And yes of course get the CEL read and report back

It's the bypass valve and the orientation of it on the 4.0.

Wix 51515 or Napa gold 1515 are the quality over sized filters. Cruiser will tell you the normal filters. As for oil. I've used Mobil 1 full synthetic and rotella 5-40 t6 and have been happy

Oh boy. I won't use a Fram again now. I won't get the readings before Monday and I will post that on here. I will replace the oil and oil filter as well. Any recommendations on which synthetic oil or if Castrol Edge is fine?

Thank you!

On another note, I have not changed the spark plugs in about 50K miles. The previous owner had never done the same. The Jeep starts up just fine, even in winter months if I leave it parked for a few weeks. Time for some TLC for the Jeep - I'll change those as well.

Thank you for listening and understanding. Some guys never have issue with Fram until they over day they do. As for oil. People are biased here to be honest. Like I said what I personally use without issue. With oil, as long as you change it as you should, you're aright

What year you have. That will drive which plugs. On my 01 I use NGK Zy5frn V power ones.

I have a 2000 Jeep Cherokee Sport.

I'm pretty sure that plugs are the same for you. Cruiser will def know.

Thank you. I would think so too.