I know this subject has been beaten to death here, but I had a couple of thoughts. Here in Las Vegas the summer temps reach 112-118 on a regular basis. (130 -140 on the pavement!!) I have been running 5w-20 per Ford's recommendation. It's a '01 Ranger XLT with 22k on it and still under warranty

Now I'm concerned that this is indeed too thin of an oil for the climate here, but then I thought of something else.

Even on the hottest days, my temp gauge still says just below half regardless of the temp outside. So if that's the temp inside the motor, what difference does it make on the outside temp regarding oil weight?

Now if someone wanted to put in a more viscous oil to prevent long term wear, I guess that's a different issue.

I'm still confused about the whole thing, and don't know if I should switch to a thicker oil 5w30. Any thoughts?

 

Because the original reason Ford went to 5W20 seemed to be for slightly better fuel economy, some were concerned that it might be too "thin" to properly protect our engines under extreme circumstances. Extreme circumstances often involve not only high ambient temperatures, but also an inadequate cooling system or other problems.

However, 5W20 oils meeting the tough Ford specification seem to be very good oils. I wouldn't be concerned for your Ranger and I certainly would not prefer a conventional 5W30 to the Motorcraft (part synthetic) 5W20.

Having said that, I personally use Mobil 1 5W30. I believe it is a little better, though for most useage, probably not worth the substantial extra cost.

 

Thank you! I feel better now.

I'm still curious though about how outside ambient temps affect motor temp in regard to choice of oil viscosity. Especially if the cooling system keeps it within spec during those hot summer days.

Like I said before, even on the hottest days here my gauge reads below half. (unless it's broken!)

 

I think the answer is that once the engine is warmed up to the normal operating temperature, your engine and its cooling system/thermostat/etc is designed to run at a given temperature ...whether its 110 above, or 10 below outside.

 

That is correct. If, however, your engine is working particularly hard, or your cooling system is a little below par, and its very hot out, your engine oil may run hotter than ideal, at least in the short term. That is where higher viscosity oil may maintain lubricity better (strictly speaking, its not the higher viscosity itself that does this, but related other properties. And quality DOES count, but that'll get real complicated!).

 

I personally use 5w30 in the summer and 5w20 in the winter. Summer here in northern Utah gets fairly hot and winter is pretty cold. I like using the 5W20 in winter for the startup.... like everyone else said once your engine warms up its pretty much moot but start up is the worst part of the whole situation and I wanted something a little thinner during the winter.

 

Aren't 5W-30 and 5W-20 the same at startup, 5?
0W-20 or 0W-30 would be thinner at cold startup
than 5W-XX. Or am I confused again....

 

Theoretically, yes, depending on the quality of the oil. Actually, particularly after 5000 miles, not necessarily.

Also, the "winter rating" is actually at a fairly high temperature (I think its freezing, 32 degrees F), and may not give sufficient information on those 20 below mornings.

 

http://www.epa.gov/otaq/cert/dearmfr/ccd0006.pdf

Take a look at this if you doubt the reason behind th 5/20 requirement from Ford.

 

Yeah, but....

I can't help but notice that the 5W20 UOA reports I've seen posted on the internet (BIOG site, for example) and had done personally on my various vehicles have turned in some of the lowest wear numbers compared to other higher viscosity oils.

5W20 may have been born out of CAFE interests, but I'm beginning to wonder if it may not turn out to be a good engine wearing oil in the long run as well.

 

My owners manual says 5W 20 Motorcraft synthetic blend which I just changed today at 3700 miles, while it's under warranty I probably won't stray from that.

 

I would suggest that you do a search on this board as to what spec the 153-H entails. After you read the spec, you most likely won't use anything else. To put it short, it is required to run cleaner, have fewer deposits, and the allowable viscosity increase is less than with any other oil including synthetics. The spec also requires the time set on the test to be DOUBLE the test for regualr oils. There is a lot more to the 5w-20 oil than just a lighter weight and CAFE,- a lot more.

 

One of the reasons I use Mobil 1 is that, even in the 5W30 and I think, the new 0W20 (Ford spec), it is rated for Diesel service (CF). The Motorcraft 5W20 is not. This would seem to be an advantage.

Comments?

 

Why is CF an advantage? I've never paid attention to diesel specs before when picking auto oil.

 

On an unrelated note. Our fleet chevy impala's run a test oil with an approximate weight of 5w-30 which meets all of our warranty requirements. We do 5k mile tests and change at 10k miles with several spot checks at intervals of 1500-2750 miles. The oil life meter on our cars usually lights up between 1300 miles and 2500 miles ( Yeah we run the living tar out of these little motors, in summer temps that exceed 150 degrees at pavement level. With water temps that hover between 195-260 degrees depending on how well the under-designed cooling systems are working. These cars often exceed 85 mph for several hours a day in mixed stop and go with bouts of wide open runs for 25-70 miles one way.) The oil is usually jet black by 2k miles. By 10k miles it looks like runny tar and smells like one of those roofing tar trucks with the oil burner boiling the tar. So far we have had no troubles with many of our cars topping the 50k mile mark. ( Many of us never thought they would make 25K).

My point is that I don't really think it matters all that much what weight you run as long as you keep the temp in a workable range and the engine is designed to run on that oil. I wouldn't run 5w20 in my 78 any more than I would run 50W Racing oil in my 98 Toyota.