Well not exactly. This is true at beginning of oil change but the viscosity additives added to the base 5 wt oil lose their effectiveness over time as the stiff polymer chains tend to relax.
But I agree there is no advantage to switch to 10wt other than getting the gage to read a little higher which is a psych thing.
Which brings up the question for the OP; how long has this oil been in there?
He is also located in the same area as me and the temperatures here have gone from frigid to unseasonably warm. If his temperature is actually peaking at 220 like he said it was that could bring his pressure down. Also, if he is having overheating problems that can accelerate the degradation of the oil. Just some more food for thought.

 

I just put this oil in there a little over 2 weeks ago, about 700 miles on it. It is overheating because the factory temp sensor doesn't read above 190/200 until the actual temp is about 240. So it doesn't kick the fan on until then. I replaced the sensor before I got the second gauge too. I'm going to do a manual switch for the fan tomorrow as well if I have the time.

Also, I guess it doesn't make sense to change to 10w just yet. I'll just grab a wix or mopar filter and swap it out. And then go to 10w later into the life of the oil.

 

You have put your finger on the problem. Fix the cooling problem and the oil pressure will return to normal.
BTW if you need Jeep parts there is jeep salvage yard in Four Oaks. I just bought a 2004 4.0 engine from them,they're good people.

 

If I'm understanding this, the oil is getting very thin because of it running around 220, and if I can get the temps back down to 195ish it will help the problem?

If so I may replace the factory temp sensor along with the fan switch so it should kick on by itself sooner.

 

It's probably true for most, if not all, of say a 5K mike oil change interval.....and a 0W30 oil would be even better.

 

Please explain.

R u using a OE factory coolant temp sending unit with a aftermarket temp gauge? If so, that's likely a problem. Aftermarket temp gauges come with their own sending unit and it must be used. U can't mix/match sending units and gauges.

 

Sounds like a stuck gauge

 

Oh no I have a t fitting in the heater hose with a sensor for the aftermarket gauge.

 

......and it is the aftermarket sensor that came with the aftermarket gauge?

 

Yes sir

 

Your efan should be on at 218. The CTS, in the stat housing, signals the ECU, which signals the OE temp gauge needle and the efan on/off.

 

Yeah I know, my factory CTS isn't accurate and thinks that 218 is 240 and doesn't kick the efan on until then.

 

Pull it and polish the probe with something like a 3M pad. Although mine,which was BLACK,didn't affect my e-fan function it,in conjunction with a dirty ICU,was giving me a low idle problem. The tarnishing was affecting the ohms spec enough to affect my fuel/air mixture. Can't hurt to try it.

 

Do u know what your oil temp is vs coolant temp? The second number of multi-vis oil is rated at 100C/212F. The difference in a XW30 oil viscosity at 212F oil temp vs 220F oil temp is negligible. Remember, oil flow equals lubrication, not oil pressure.

Until u have your oil pressure tested, with a mechanical oil pressure test gauge, u r just guessing that u even have a oil pressure issue and that your aftermarket gauge is accurate.

Until u have your coolant temp verified (which will verify if your aftermarket gauge is accurate), u r just guessing that u have a faulty CTS/efan/overheat issue.

 

Yes but that small difference will result is seeing lower pressure at idle.
With the oil pump spinning at only 300rpm it does make a difference.
His pressure is still within spec and is normal at higher speeds. I just used this as diagnostic data to point him to a possible overheating issue....which appears to be the case.