Thinnest possible oil you can put in a car?

[Greasymechtech]

Why no year make model.....?

 

[Graham Piccinini]

I put Idemitsu 0w-20 in a 2000 Honda CR-V (AWD and 5-speed, ~225k miles) for a couple oil changes. Seemed to hold up fine, no UOA, and same oil consumption as any other viscosity I've tried. No change in fuel economy, so I switched to M1 0w-30 now. Just running what's in my stash and that engine doesn't seem to care what oil to burn. "If an old Honda doesn't burn oil, there is none left in it."

 

[ARCOgraphite]

Didn't know sae had 0W2
Is that a typo?

I would stay away from that oil, A stupid company name, snake oil "additives" and incorrect use of SAE oil grading.
All that together spells trouble.

I bet any of the racers "special stuff" is in white 5 gal pails with sharpie markings or a hand typed label glued ton the bucket

 

[ARCOgraphite]

My brother has an old car and currently has a 120 mile daily highway drive.
He asked me what i could do to make it absolutly as fuel efficient as possible.
I said it probably wont make a lot of difference and maybe try a simple thing like putting a little more pressure in the tyres.
And if you want to make it extreme take a thinner engine oil and trans oil but there are hazzards attached to doing this and i wont recomend it for the very smal gains.

He however wants to try it so i looked into some oils.

Its a 2004 1.6 16v gasoline engine with 110hp and 5 speed manual trans, oem spec oil is 5w40.
Currently theres motul 5w40 in it which has a the following specs:

Viscosity grade SAE J 300 5W-40
Density at 20°C (68°F) ASTM D1298 0.851
Viscosity at 40°C (104°F) ASTM D445 85.4 mm²/s
Viscosity at 100°C (212°F) ASTM D445 14.2 mm²/s
HTHS viscosity at 150°C (302°F) ASTM D4741 3.7 mPa.s
Viscosity Index ASTM D2270 172
Pour point ASTM D97 -36°C / -33°F
Flash point ASTM D92 230°C / 450°F
Sulfated ash ASTM D874 1.1% weight
TBN ASTM D2896 10.1 mg KOH/g

I looked into ravenol 5w20 SFE which has the following specs, i liked it because i think its a pretty ''thick'' 5w20 and has a HTHS of 2.9

Density at 20°C	kg/m³	843,0	EN ISO 12185
Colour		braun	visual
Viscosity at 100°C	mm²/s	8,5	DIN 51 562
Viscosity at 40°C	mm²/s	47,2	DIN 51 562
Viscosity index VI		160	DIN ISO 2909
HTHS at 150°C	mPа*s	2,9	CEC L-036-90
CCS Viscosity at -30°C	mPa*s	3640	ASTM D5293
Low Temp. Pumping viscosity (MRV) at -35°C	mPa*s	6.700	ASTM D4684
Pourpoint	°C	-63	DIN ISO 3016
Noack Volatility	% M/M	8,3	ASTM D5800/b
Flash point	°C	238	DIN ISO 2592
TBN	mg KOH/g	8,8	ASTM D2896
Sulphated ash	%wt.	1,07	DIN 51 575

These engines are known to be pretty bulletproof , i used to own one and did a lot of 120mph prolonged highway runs where oil temps would reach 285f 140c, that was also on 5w40.


Does anybody have experience with switching to thinner oils? Did you encounter problems with this? Normally you can pretty safely switch from 5w40 to 5w30, however from 5w40 to 5w20 is a large step.

Basicly as long as the oil pressure is stable and high enough i dont forsee any real short term problems, except maybe some more oil consumption. (normaly these engines use absolutly 0)

I told him its a pretty large risk to take suchs large steps for almost inmeasureable amount of fuel consumption reduction. But he wants to try it.

You can get these engines for around 100 euros at local junkyards so its not that big of a risk. As i said they normally never fail so they are not that sought after.

Over in the U.S. that engine (Toyota? Nissan?) would likely have spec'd an API SL /ILSAC GF-3 5W30 with HTHS >3cP.
That's as low as I would go with that engine NEVER a 20 grade.
Most beneficial He could add a home made chin spoiler to keep air out of the underbody.
Where is he driving 120 miles in the Netherlands? on the A50?
- Ken

 

[Blinker]

No when the term “properly inflated” is used. A lot of drivers are running on under inflated tires due to ignorance or laziness.

This. Most people I know don’t give a second thought to tire pressure unless the TPMS light comes on.

 

[ARCOgraphite]

This. Most people I know don’t give a second thought to tire pressure unless the TPMS light comes on.

I can't count the number of women in minivans and suv's that I have encountered
with a rear tire almost deflated to the rim. I engage with them at the next stop light
but they just drive off, then get onto the Interstate and crank it up to 70MPH!

 

[Flyingdutchman]

For my BMW i will probably order a 20l jug of Fuchs 5w30 LL04 spec oil because it consumes a lot and from germany this is pretty cheap at 4 euros a litre.

I will probably use this like a fleet oil for my families vehicles and some friends of mine. All are older cheap early 2000s pretty regular low horsepower verhicles.

This is a 5w30 with a HTHS of 3.5.

I am sure that this will not cause any harm to the engine. Ive read more stories on forums where unknowing shops just threw 5w30 in it because they have it in bulk and the engines ran fine.
Switching to 0w20 would be a different story however.

 

[samven]

If the idea is to save money and not just see how much mileage you can get it makes no sense to spend 80 to save 10 and take a chance you might shorten its life. Remove the weight from the car and the gas pedal, check all your wheel bearings and make sure the brakes dont drag and only drive with the wind at your back and down hill.

 

[alcyon]

At 120mph, at nearly 5000rpm, I would stick to 5W-40. Most of your fuel economy loss at that speed is wind resistance. Driving at about 80mph is the best trade off between fuel consumption and getting to your destination quicker.

 

[ARCOgraphite]

For my BMW i will probably order a 20l jug of Fuchs 5w30 LL04 spec oil because it consumes a lot and from germany this is pretty cheap at 4 euros a litre.

I will probably use this like a fleet oil for my families vehicles and some friends of mine. All are older cheap early 2000s pretty regular low horsepower verhicles.

This is a 5w30 with a HTHS of 3.5.

I am sure that this will not cause any harm to the engine. Ive read more stories on forums where unknowing shops just threw 5w30 in it because they have it in bulk and the engines ran fine.
Switching to 0w20 would be a different story however.

The high HTHS 5W30 is NOT going to save you fuel. I would got with a Mid saps Mid HTHS oil like a
5W30 Dexos approved ILSAC GF5 or GF6 oil. But Seeing how old his car is, I'm not sure if I would drop a grade or HTHS.

Again, adding chin spoiler/air dam to the front of the car under the bumper and maybe a rear roof or decklid
mini spoiler to get the turbulence past the tail of the vehicle at highway speeds. Also block off 1/2 the radiator frontal area at the grill in colder weather.

Oil is going to have little impact - except on the "warmup" drive to the highway

 

[ARCOgraphite]

At 120mph, at nearly 5000rpm, I would stick to 5W-40. ......

😲😱

 

[Obi Wan Noobi]

Its a 2004 1.6 16v gasoline engine with 110hp and 5 speed manual trans, oem spec oil is 5w40.

It's not a good idea to stray away from the OEM spec for two reasons:

1. Even ACEA A3/B4 oils have become thinner over the past 16 years or so. Castrol EDGE 5W-40 is basically a 5W-30 for all intents and purposes. They pushed the operating temperature viscosity to 12.9, on paper, to make it qualify as a 5W-40. Ridiculous...
2. It's an old car, old engine, so going to a 0W-20, you will accelerate wear.

Good luck though, you'll need it with... 0W-20... an oil thinner than Diesel fuel.