3.6 Pentastar viscosity done by clearance and temperature

[Camperguy]

So I did an oil viscosity search different. I took engine clearance/ambient temperature and oil temperature into consideration. Using 100F ambient/coolant temps that average 220-240f and oil temps that constantly are over 200+. Yes the Pentastar has a coolant to oil heat exchanger but it's not over %100 efficient nothing is. If you've worked on them, seen the size and know there location you would probably be amazed if they were 50% effective. Working with a standard .0025 clearance and temperature it looks like a 40 weight oil is recommended. What are your thoughts?

 

[JavierH19]

Wow, took almost 19 years to make the first post, must be a record.

 

[4WD]

So I can do 0W40 !

 

[JavierH19]

And yeah you can use 40 grade if that's the case.

 

[nascarnation]

What's the typical failure mode on these engines? Is it oil related or something else? If it's oil related that might help. I know the transmissions on these are known for converter bearing problems but the engines seem pretty robust and I assume most are running on generic Jiffy Lube or similar levels of maintenance.

 

[Brian123]

Wow, took almost 19 years to make the first post, must be a record.

Maybe he forgot his Password and he just found it!

 

[Camperguy]

It seems to be the needle bearings in the rocker arms then it Cascades to the camshafts taking out the the cam timing system. That's seems to be the most common problem I could find with the 3.6 that and rod bearings.

 

[Camperguy]

Ahhh no, I'm just doing some research. I use this site for research and experience. I thought I had an account

 

[Camperguy]

Holysht, 2005

 

[Brian123]

Ahhh no, I'm just doing some research. I use this site for research and experience. I thought I had an account

You have an Account, you have been a member here since 2005

 

[cptbarkey]

I am going to assume this Pentastar is a Grand Caravan that is being drag raced, so go with their recommendations. Good luck and post videos.

 

[Camperguy]

Yep I joined in 2005, I obviously forgot that I had. I Probably had nothing interesting to add. I keep hearing about newer engines/tighter clearances thinner oil that's why I put this up. I'm not seeing anything super refined on the 3.6. seems to be a middle range build.

 

[Camperguy]

I am going to assume this Pentastar is a Grand Caravan that is being drag raced, so go with their recommendations. Good luck and post videos.

Nope just a Jeep Rubicon that I wheel in the Desert and drive on the street. I noticed my oil catch can filled up 3oz every 1000 miles on 5W-20 and less about an oz every 2k on 5w-40. About as scientific as I can get without a gas chromatograph

 

[Vitamin Yoda]

I'm using Mobil 1 FS 5W-30 in one Pentastar V6 PUG, the other one I use Castrol EDGE EP 5W-30. This one will soon get an oil with higher 3.5+ HTHS as well. I've noticed no negative impact on fuel economy by going "thicker" so to speak. Also, a 0W-40 would probably work even better than Euro 5W-30 because of the better cold start performance.

 

[4WD]

5W30 in my Rubicon (Pentastar) …

 

[CarbonSteel]

The oil temperature and coolant temperature is 100% connected on these engines due to the design. It is a terrible design and mine starting leaking at 50K miles. The Wrangler struggles to maintain temperature control when stock, much less modified and used as a Jeep off-road.

I saw 235°F almost always as a minimum temperature off-road and 225°F on-road. I would not hesitate to run xW-30 in it. I ran Mobil 1 ESP 0W-30.

I have a friend in TX who has ran 0W-40 in his from the first oil change. He has over 130K on it now and runs quietly and has had zero issues.

 

[Camperguy]

Ive seen 240 water temps pretty often in the summer driving grades/off road. I installed a new thermostat, water pump, radiator, silicone hoses and a new aluminum oil filter housing at 60k miles.I also cut one of those Poison Spider hood vents in.Personally been using 5W-40 Platinum Euro since my first summer here. Interesting site, glad I'm not the only one obsessed with oil, hell it even has trolls

 

[Accent Abuser]

So I did an oil viscosity search different. I took engine clearance/ambient temperature and oil temperature into consideration. Using 100F ambient/coolant temps that average 220-240f and oil temps that constantly are over 200+. Yes the Pentastar has a coolant to oil heat exchanger but it's not over %100 efficient nothing is. If you've worked on them, seen the size and know there location you would probably be amazed if they were 50% effective. Working with a standard .0025 clearance and temperature it looks like a 40 weight oil is recommended. What are your thoughts?View attachment 202844View attachment 202845

This is the same chart I compared my Hyundai Accent to, and it led me to pick 5w40 in the winter and 15w50 in summer. At 230,000 miles the engine is in just as good a shape as it was at 60,000.

If maximum wear protection is more important than a small difference in gas mileage, viscosity is what protects an engine above and beyond anything else.


I can also say as a mechanic who does oil changes regularly, oil in winter is definitely cooler than summer oil, even if the coolant is at operating temperature.

 

[HoosierJeeper]

Interesting, I'm getting ready to do another oil change on my JLU with the 3.6. I thought the revised 3.6 like I have was designed for 0w20 with thinner passageways and that was the best for it. Wrong?

 

[demarpaint]

Interesting, I'm getting ready to do another oil change on my JLU with the 3.6. I thought the revised 3.6 like I have was designed for 0w20 with thinner passageways and that was the best for it. Wrong?

CAFE. You can easily bump it up a grade, or two.