20wt.....why? 30wt.....

Messages
575
Location
Connecticut
Originally Posted By: Steve S
Doing a double blind test?,,, I changed from 5w-30 to 5w-20 Pennzoil Platinum and he did not notice any difference when I asked if there was one.
That is actually a blind test, or a single blind. If you had rigged the test so that you yourself didn't know which oil was which, that would be a double blind.
 
Messages
1,649
Location
Bowie, MD
Originally Posted By: Pop_Rivit
Can someone point me to information about the failures, damage and reduced longevity caused by running an Xw-20 in the summer months, even on a vehicle that sees high outdoor temperatures and cars that see heavy loads? I see a lot of suggestions (by some) that a 30 weight is better for summer or "tough" use, but I don't see any of it backed up by real proof. That assumes the vehicle is spec'd for a 20 weight. I'd love to see the actual proof-it would be interesting reading.
I don't use 5w30 in the summer because of a threat of immediate failure if I use a 5w20. Using a heavier oil is a choice to take a precaution against additional wear that may or may not happen. Even if extra wear does happen, it won't cause immediate failure. I also happened to have some 5w30 that needed to be used since I had some in the stash after getting rid of the 5w30 spec car I used to use. I guess the way I see it, high temps make it so that you can "get away with" using a 5w30 instead of a 5w20
 
Messages
424
Location
Toronto, ON, Canada
Originally Posted By: Pop_Rivit
Can someone point me to information about the failures, damage and reduced longevity caused by running an Xw-20 in the summer months, even on a vehicle that sees high outdoor temperatures and cars that see heavy loads?
I read from an acura forum the engine block (J32 engine) failed due to thin oil + high temp + high rpm. The engine failed at around 80k.
 

FZ1

Messages
4,727
Location
Texas
I prefer to run the oem spec weight oil year round. It's 5-20 for my Accord V6. I run synthetic to get better flow and performance. I don't think thicker oil,than spec,is more protection......I would think is more engine stress,friction,and heat,than a thinner oil.
 
Messages
1,623
Location
western australia
Possibly 5w20 in "winter" if the climate allows it and fuel dilution is not an issue. Are there any specific Toyota approvals required for this engine ? Some on the board are quick to generalize and reduce grades because it is fashionable and impose their views as facts. I know the Doc reduces his by a couple of grades but he does UOA testing and is quite aware of conditions he is exposing his engine to and defends his case very well. Some other well respected members, especially where there are specific engine approvals for a particular engine, warn and make it clear to use only oils (and grade) with the required OEM approval. As this is a question open to opinions be clear why as to you wish to change and accept responsibility for your decision.
 
Last edited:
Originally Posted By: BigJohn
I hear a lot of people on this forum talk about the need to use 30wt instead of 20wt, when towing. So here's the question... Hasn't Ford, in their 1/2 ton pickups, spec'd 20wt for several years? I wonder how service trucks are performing with 20wt. For instance the oil and gas industry uses thousands of these trucks in the oil field. Also, cities and counties across the nation have fleets of these pickups.... Surely there is data somewhere.....???? I do have to admit that I would lean to 30wt in summer and when towing....so I am in that camp until some data surfaces that proves it wrong.
You have to remember that all of these generalizations will NOT lead you to the proper answer for your vehicle. A Toyota 4-Runner is not a Ford F150. Oil temperatures may be different under heavy loads, from the winter to summer, etc. Different vehicles are just that... Different. I believe Jim Allen enlightened this board with data from his F150 V8 stating that under all kinds of different conditions, his oil temperature did not even reach boiling point. It was even colder in the winter, even after prolonged driving. This has a huge impact as to why many Ford F150's work very well with 5W20! You would need to do the same with your 4-runner in order to conclude that you also would be safe with a 5W20 as opposed to a 5W30 in all of the conditions that you encounter. You might find that you would be absolutely safe, or you could find that when towing with your rig the oil temps get a bit higher than you'd like to see with a 20 grade in there. Different cars... Apples to oranges...
 
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