PP - Mix 5w30 & 0w40?

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I had the pleasure of going across the border and buying some of the European Formula 0w40 PP.

With my new stash of PP 5w30, can anyone come up with any good reason not to mix the two? They are both pure base derived, both SN spec.
 
I still don't understand the whole concept of mixing different grades. Why not run it exclusively for one OCI and then go back to the 5W-30 stuff? What's it going in?
 
What's the positives of mixing those? I understand mixing a thick and a thin eg. 40 with 20 but there's probably not a lot between the two you have. My vote goes to no
lol.gif
 
I have a couple of quarts of 0w40 PU from the AZ 'Clearance' that I will probably mix with 5w20 to get rid of it.... but I certainly don't think that 'mixing' will create something better than either oil individually.
 
Think about viscosity. I don't want a 40 weight with a super high HTHS. But I wouldn't mind increasing the 3.0 HTHS and 10.3 hot viscosity a little while severe service towing.
 
Originally Posted By: FermeLaPorte
It's pennzoil, I think they never perform well

Based on?
 
While towing up the hill towards Cape Smokey (Cape Breton, Nova Scotia) on our recent family adventure, my coolant temp spiked to 115 degrees Celsius (239 Fahrenheit). If I had followed Dodge recommendations with a 5w20 I would have had a viscosity of approximately 6 cSt during that climb, assuming coolant temp = oil temp.

With PP 5w30 it was around 7.72 cSt, using online temperature viscosity calculators.

For comparison, PP Euro 0w40 would have had a viscosity of 9.71 cSt under similar conditions.

Food for thought for those that blindly follow manufacturer recommendations.
 
They're usually about 10C difference under normal conditions. No way to know unless you have an oil temp gauge. Depends on RPMS too. Sustained high rpms heat oil up faster than load does. Your thermostat working ok? 115C seems very high. Was it a super hot summer day with no air flow or something?
 
About 25 degrees Celsius ambient, ~3000 - 3500 rpms, slow speed (not much airflow). Steep climb, pulling a 2000 pound load, with family of four (+ dog), and related gear for a 3 week road trip. I was surprised to see the temp gauge climb past half way and reach 3/4. Had the scan gauge plugged in for the trip. Interesting stuff learned about coolant temp, ignition timing, load and intake air temps.
 
Check your thermo fans come on at the right time too. They usually come on around 100C on most cars and sometimes go to full blast mode at 110C.

Some manufacturers state to use higher viscosity when towing. Is there anything about that in your manual?
 
Originally Posted By: KL31
Check your thermo fans come on at the right time too. They usually come on around 100C on most cars and sometimes go to full blast mode at 110C.

Some manufacturers state to use higher viscosity when towing. Is there anything about that in your manual?


There is no language in the manual as such. Just the recommended 5w20.
 
Originally Posted By: SilverFusion2010
Oil cooler?


Yep, OEM oil cooler that comes standard with a 2017 GC.
 
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