My experiences with thin oil

[HTSS_TR]

My '00 MB E430 just passed 100k miles, I bought it new in April 2000, it had M1 0W40 as factory fill and every oil change until March 2008.

After reading Dr AEHaas writing about thin oil and his experience in using thinner oil in his cars, I decided to try PP 5W20 in E430 in 03-08. Immediately I experienced several things: Engine was much quieter at all RPM specially at idle while waiting for green light. Second is gas mileage improved by more than 4-5% according to on-board computer, it was 17.5-18.5 mpg with M1 0W40, with PP 5W20 mpg improved to 18.8-20.2. Third, coolant went to operating temperature faster with thinner oil. Fourth, PP color got darker much faster than M1 and became black after only 3k miles, while it took more than 5k miles for M1 to become black.

Last July I went to Vegas and got stuck (mostly stop and no go) at Death Valley for almost 3 hours with 120+ degrees to go less than 5 miles, coolant temperature at almost 100* C. Everything was okay and gas mileage went to 26.4 mpg which is more than 2 mpg better than ever before, with same trips and same speed I got 23.2-24.5 mpg.

I was nervous for extreme temperature so that I changed oil in August to Delo 15W40. Immediately, engine noise was back and mpg went south.

I wasn't happy with it at all, so that I changed to M1 0W20(4 quarts) mixed with 10W30(3.5 quarts) + 8 ounces VSOT. Engine is quiet again, mpg went up but not a good as it was with PP 5W20. Just came home after another trip to Vegas, mpg for the round trip was 25.6 mpg compares with 26.4 mpg last summer. Some of the decreasing mpg may be because of winter gas. EPA rating for this '00 E430 was 17 mpg in city and 24 mpg on highway.

My personal conclusion is thinner oil does increase gas mileage and it reduces engine noise (at least in my particular E430). It may increase engine wear, but I don't have evident to back it up because I did not do UOA before and after using thinner oil.

Since the car has more than 100k miles, I don't care if engine wear is accelerated with thinner oil, I love the quiet that the engine does with thinner oil I will use it in the future.

 

[RISUPERCREWMAN]

My 2007 Ford F-150 5.4 3v uses 5w-20 as the factory fill, I have been using Mobil-1 5w-20 since 1st oil change with remarkable results as far as engine quiet at startup,running,& MPG's.....I will run this oil as long as the engine lasts! I change @ 4K mile intervals.

 

[BigJohn]

Really good to know that you had great results with PP 5w20....for sure that is my new winter oil. For some weird reason, I just can't go to a 20wt for summer time...despite your awesome report from Death Valley. PP 5w30 will be my summer oil.

 

[bustednutz]

I don't think that going to a 30wt in the summer is necessary. Afterall your engine always runs at the same temp year round. An engines temp is regulated by the cooling system so that it maintains a constant temp, regardless of the season.
A low weight for cold start is a different thing, but at full temp, a 20 wt will be fine year round.

 

[xBa380]

I have been running 0W20 for the last four oil changes and my first UOA I just got back had lower wear averages then reported. Very impressed and will continue to use 0W20 year round.

I used M1 0W20 the first two times and PP 0W20 the last two times. PP is quieter at the end of my mandatory 5K OCI.

 

[AEHaas]

I have been using 20 grade oils in Maybachs, Ferraris and Lamborghinis for 4 - 5 years and as yet nothing blew up and UOA have been better than others using thicker, OEM oils, in the same cars.

aehaas

 

[HTSS_TR]

A few things I forgot to mention, operating coolant temperature was around 85-86C with M1 0W40 and Delo 15W40 even during Vegas trips in the winter. It was 83-84C with PP 5W20 last summer but only 81-82C with M1 0W20-10W30 mixed in both city and highway speed.

Last summer average ambient temperature in So Cal was mostly 70-80F, rarely it went over 90F. Ambient temperature on the Vegas trip was mostly in the high 30's or low 40's.

This leads me to believe that engine is running cooler with thinner oil.

 

[HTSS_TR]

Your experiences and your writing about thinner oil made me try it. So far, I love it and my wife loves it too for quiet in the cabin without engine noise intrusion. She doesn't care about gas mileage and/or engine wear or anything else, as long as the car running quietly.

 

[hate2work]

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

If they don't make one by the time I'm out of ASL next Spring, I might have to switch to PP to try the thinner oil.

 

[The Critic]

Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?

 

[Stanley Rockafeller]

Originally Posted By: The Critic
Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?


Ed Zachary!

 

[Ken42]

Nobody mentioned the dirty factor? Wonder if that is cause the thinner oil is able to get into the smaller nooks and carnies of the engine?
Ken

 

[BuickGN]

Originally Posted By: HTSS_TR
A few things I forgot to mention, operating coolant temperature was around 85-86C with M1 0W40 and Delo 15W40 even during Vegas trips in the winter. It was 83-84C with PP 5W20 last summer but only 81-82C with M1 0W20-10W30 mixed in both city and highway speed.

Last summer average ambient temperature in So Cal was mostly 70-80F, rarely it went over 90F. Ambient temperature on the Vegas trip was mostly in the high 30's or low 40's.

This leads me to believe that engine is running cooler with thinner oil.


So thinner oil has made your thermostat crack open at a lower temp....

 

[HTSS_TR]

Originally Posted By: BuickGN

So thinner oil has made your thermostat crack open at a lower temp....


I don't know why the coolant temperature is lower with thinner oil, the thermostat is original OE and the same for all hoses. Logic tells me that engine may run cooler with thinner oil but coolant temperature should be the same.

The only time the coolant temperature got into dangerous zone, almost 100C, when I got stuck uphill in Death Valley at noon on July 04, when ambient temperature was more than 120F for more than 3 hours (with air conditioning running full speed).

I drove fairly fast to Vegas many times with the same cars, cruise control was set at 85-90 MPH and accelerated to 95-100+ to pass if needed. Because of fairly high speed driving, I scan the instruments every few minutes to make sure nothing was out of whack before too late. Coolant temperature is the one I paid most attention to, because the car doesn't have oil pressure nor oil temperature.

 

[hate2work]

Originally Posted By: The Critic
Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?


Well, I'm sure it's good oil, but my engine is not spec'd for it, just 5W-30 and 5W-20.

 

[OVERKILL]

Originally Posted By: hate2work
Originally Posted By: The Critic
Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?


Well, I'm sure it's good oil, but my engine is not spec'd for it, just 5W-30 and 5W-20.


0w20 is designed as a replacement for 5w20 in applications that call for it. As 0w30 is the same with 5w30 applications.

 

[hate2work]

Originally Posted By: Ken42
Nobody mentioned the dirty factor? Wonder if that is cause the thinner oil is able to get into the smaller nooks and carnies of the engine?
Ken


I think the general consensus is that it flows better.

What's the dirty factor?

 

[demarpaint]

To me the increase in MPG means less friction and drag, that would equate to less wear in my opinion. If MPG dropped and the engine was running hotter then I would say more friction, more drag, more wear.

JMO,
Frank D

 

[hate2work]

Originally Posted By: OVERK1LL
Originally Posted By: hate2work
Originally Posted By: The Critic
Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?


Well, I'm sure it's good oil, but my engine is not spec'd for it, just 5W-30 and 5W-20.


0w20 is designed as a replacement for 5w20 in applications that call for it. As 0w30 is the same with 5w30 applications.


No kidding? OK, so THAT'S why they don't make a 5W-20 full syn.

 

[BigJohn]

Originally Posted By: hate2work
Originally Posted By: The Critic
Originally Posted By: hate2work

I wish Amsoil made a 100% synthetic in 5W-20, I think it would be very popular. But I realize they can't make every possible combination.

What's wrong with their ASM 0w-20?


Well, I'm sure it's good oil, but my engine is not spec'd for it, just 5W-30 and 5W-20.



By way of a Toyota Service bulletin, saying that they now approve T4R's for 5W20....I was ALL OVER, beginning to use M1 0W20....which is a superior oil to 5w20.

Honestly, I would like to see the Toyota Lab prove that they can.... #1 determine that 0w20 is worse than 5w20....and #2 determine that the 0w20 in the engine caused any trouble with any warranty work that will be needed.