Pentastar 3.6 oil pressure

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I wanted to know if any forum members had any insight on Pentastar oil pressure issues. I have a 2012 Jeep Cherokee 4X4 with 3900 miles. Now to the issue. My oil pressure runs between 68 to 80 psi until the oil temp hits approx 158 degrees. It takes several miles for the temp to reach that with the factory oil cooler.Once the oil hits the right temp the pressure drops to around 30 psi.Anybody have any thoughts, theories ,similar experiences or info on this engine? Thanks
P.S. The oil temps never goes above 179/180 degrees
 
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Our pentastar equipped vehicle did the same, I beleive the oil pump is 2 speed, runs on high until temp comes up and than anything over 3k rpm (not sure about exact rpm) the pump runs on high.
 
Same for me. It is almost instantaneous. 70 psi down to 30 psi in a few seconds.
 
Quote:
A chain-driven, vane-type variable displacement oil pump adjusts the flow rate and pressure as commanded by the engine management system, which uses a solenoid to drive the pump into low or high pressure mode. For example, below 3,500 rpm, the pump conserves energy by using low pressure; at speeds over 3,500 rpm, the pump switches to high pressure.

A force balance mechanism inside the oil pump adjusts the size of the pumping chambers to alter oil flow. If the oil is cold, the pump reduces the size of the internal chambers. When the oil is hot and thinner, more oil is needed, and a spring increases the size of the pump chambers. This also saves energy.

The pump is driven at a 1:1 drive ratio; its location under the block is more efficient than an on-crankshaft location. An internal, mechanical ball-and-spring relief valve dumps oil into the sump when needed, for conditions such as a cold start with high engine speed. Both pump and pressure regulation solenoid are non-serviceable.


Source Pentastar.com
 
I have 2 2012 Charger SXT's with the 3.6 Pentastar. I have been very happy with them. The oil pressure (OP) is very much like yours, when the temp of the oil reaches approx 174F the pressure goes from the 70-80PSI range to 35-41PSI range. The hottest my oil has gotten is 214F in stop and go traffic mid summer. The Lowest the pressure has gotten is 25PSI at idle in drive. I do find it "funny" that at exactly 174F the pressure drops but pressure is higher with thicker oils and thinner oils cause lower readings.
 
i have heard of problems with those engines but have never seen any at my engine shop. A lot of new engines have ticks and knocking sounding noises that do not do any damage. Some have loud vvt some have other noises but a lot of the new engines seem to be a lot louder than the older ones.
 
I had a rental Chrysler 300 a few months ago and the oil pressure behavior was the same as you are observing. It's 75-90 psi for a while, then BAM, it drops to 25-40 psi and stays there, unless you hit 3,500 rpm, then BAM, it's back up to 75-90 psi. Odd, and you can feel it in the engine if you are feeling for it. The note of the engine changes just ever so slightly when the oil pressure spikes at 3,500 rpm.
 
The new vane pumps are very different from the gerotor style we are used to in most cars.

Add in the variable displacement feature and you have a bizarre readout to study for the "new normal".

many newer engines are now using this style oil pump. Since all the variable cam timing and cylinder deactivation strategies are operated hydraulically by oil pressure the new engines require a larger volume of oil flow.
 
Originally Posted By: cptbarkey
electric oil pumps... dont quite like the sound of that at all.

everything i read says it is chain driven! the elec part controls high or low pressure. from what i understand the motor can survive just fine on low pressure.

"A chain-driven, vane-type variable displacement oil pump adjusts the flow rate and pressure as commanded by the engine management system, which uses a solenoid to drive the pump into low or high pressure mode. For example, below 3,500 rpm, the pump conserves energy by using low pressure; at speeds over 3,500 rpm, the pump switches to high pressure."
 
Originally Posted By: cptbarkey
electric oil pumps... dont quite like the sound of that at all.


The pump is simply electronically-controlled...it is still mechanically-operated via a chain from the crankshaft snout. Exactly like the cam timing on your Sienna...electronically-controlled by the PCM, but still mechanically-operated via a chain from the crankshaft snout.
 
I finally started recording my oil pressures, had to give up on the Torque app on my phone, haven't been able to get it to read a lot of stuff on the Charger.

Anyway, I ran it up to 3500RPM today and did notice the drastic jump in pressure there, about 200 kPa or 29 PSI on warm oil.

My reason for calling up this old thread though is minimum pressures. Has anyone noted what their pressures are at lower RPMs? Minimum at 1200 RPM with warm oil is supposed to be 206 kPa or 30 PSI. I'm now running PP 5w20 and only seeing temps around 85 C (185 F) yet I'm only getting around 240 kPa or 35 PSI. Not a concern right now as I don't drive hard and I wouldn't expect to see the oil temp a lot higher over the winter. I did however see temps that were up to 95 C (203 F) over the summer. A 10 degree bump in temperature would cause a drop of around 2 cSt maybe a bit more. I am wondering how close this is going to bring me to the minimum spec and how close I am comfortable with.

If anyone could post what they are seeing with the 5w30 spec'd engines I would appreciate it. Of course 5w20 info is welcome too.
 
With a minimum spec' of 30 psi at 1,200 rpm and you're getting 35 psi at 85C on PP 5W-20 sounds in line to me and nothing to be concerned about. The oil temp' at which the test spec' is based is usually below normal operating temp's.
For example the test spec' for my Porsche at elevated rev's (5,000 rpm, and I forget the spec' on idle) is 5 bar at 80C oil temp's.
Normal oil temp's are 90C-95C. I think the lower test temp' is to take into account the fact the oil has cooled down some in the shop when the engine in turned off for a period of time.

I don't think your oil pressure would drop below 30 psi with oil temp's up to 95C but I'm sure it would if you were able to generate considerably higher oil temp's under some extreme usage but that still wouldn't indicate there's a problem. Remember the 30 psi is a just a test spec' to make sure everything is fine with no undue wear etc. It's not a proxy of the safest minimum operational viscosity for the engine.
 
With that in mind the 30 @ 1200 does seem a big jump from 5 @ 600.

Not much fear of extreme use, I'm pretty easy on it. Will be interesting to see what kind of numbers I get when things warm up again.
 
Originally Posted By: cp3
My reason for calling up this old thread though is minimum pressures. Has anyone noted what their pressures are at lower RPMs? Minimum at 1200 RPM with warm oil is supposed to be 206 kPa or 30 PSI.


Our V-6 engine specifies 10 psi at idle and 71 psi at 3,000 rpm, both at 176 deg F oil temperature.

Our I-4 engine specifies 10 psi at idle and 44 psi at 3,000 rpm, both at 176 deg F oil temperature.

I'm not sure why Chrysler would need to maintain 30 psi at idle in that engine. I remember that it would never drop below about 28 psi in the rental 300 I had (with the Pentastar). It seems unnecessarily high to me.
 
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