Will Thinner Oils Damage Your Engine?

[Zaedock]

He was a complete lad, one of my favourite members, we got along great, sucks that he's no longer here.

Yeah. I remember scoring a bunch of Delo SAE30 back in '05/'06. We both did the same "test" where will we started our cars will the valve cover off to witness immediate oil flow from the rockers with the 30 at 32*F+/-. I used the 350 in my Malibu drag car. It was very scientific...... but fun.

 

[350Rocket]

Yeah. I remember scoring a bunch of Delo SAE30 back in '05/'06. We both did the same "test" where will we started our cars will the valve cover off to witness immediate oil flow from the rockers with the 30 at 32*F+/-. I used the 350 in my Malibu drag car. It was very scientific...... but fun.

Come to think of it I still have the cheap sae 30 supertech in the Caprice right now. I bought a 19L barrel for cheap and used it as a flush oil in all 3 vehicles (so I wouldn't feel as bad leaving the filter on for a second oci) and the Caprice is slightly quieter with the 30w and no negative effects on the (admittedly warm) cold starts we get right now. It has a good battery and spins over just as fast when it's sat a couple weeks, as it did with 0w40.
In the cutlass I settled on xw30 or 0w40 m1. Anything thicker and the valve train gets noisier. Any thinner and I'd be worried.

 

[aquariuscsm]

W30 seems like a good sweet spot when it comes to motor oil, no mater what car it goes into.

 

[blingo]

Philosophising about these Mobil-Toyota-GR 300+ viscosity index oils could have become entertaining, when already teamed up anyway.

 

[buster]

W30 seems like a good sweet spot when it comes to motor oil, no mater what car it goes into.

Yeah or the HPL, Driven and Red Line 0w20's have a HT/HS of 2.9-3.0.

 

[Jackson_Slugger]

... Mazda "allows" 5w30 in europe and mexico. Higher HTHS = higher rpm protection. Going forward, I'll be using an HTHS 3.5 oil. Driving around my equinox, I have no reason to change from OEM spec 0w20 unless an UOA suggests otherwise.
...

Comments about what manuals in other nations "allow" need to be qualified or contextualized. In Mexico, synthetic oil is very expensive and may not be as readily available as here, so most use a conventional or synblend at best. And of course they are in the ubiquitous "subtropical" zone spoken in oil recommendations past. So yes they allow for thicker, (probably accounting for) inferior quality oils. Europe has a broad spectrum but again oil is more expensive (sometimes a lot more) and longer drains have been advocated in the past...

 

[kschachn]

Comments about what manuals in other nations "allow" need to be qualified or contextualized. In Mexico, synthetic oil is very expensive and may not be as readily available as here, so most use a conventional or synblend at best. And of course they are in the ubiquitous "subtropical" zone spoken in oil recommendations past. So yes they allow for thicker, (probably accounting for) inferior quality oils. Europe has a broad spectrum but again oil is more expensive (sometimes a lot more) and longer drains have been advocated in the past...

Which is fine, but regardless of the reason it does show that a higher viscosity oil is not in and of itself detrimental to the engine operation. Not saying you’re making that claim but some do.

 

[gfh77665]

My 2006 Honda Odyssey was noisy with the required 5w20. When warranty expired I switched to 5w-30 and it immediately got quieter.

I always prefer 5-30 and 10-30 in the hot Texas climate. Thins have their place in the northern tier and Canada.

 

[RDY4WAR]

My 2006 Honda Odyssey was noisy with the required 5w20. When warranty expired I switched to 5w-30 and it immediately got quieter.

I always prefer 5-30 and 10-30 in the hot Texas climate. Thins have their place in the northern tier and Canada.

I checked that out in Georgia. I always ran 10w-30 in my old Bronco and the operating oil temp was always ~220*F on the highway regardless if it was 100*F in July or 20*F in January. The only difference is it took longer to warm up in the winter, but warmed up to the same temperature. The only time I saw operating oil temp creep up was when I tried a 10w-40. My conclusion was higher viscosity = more hydrodynamic friction = more heat generated under load.

 

[bluesubie]

You'd have to spend some time searching, but an old member here Gary Allan (RIP my friend) conducted tests running a custom blend 0W10, made by another member here (I believe they called it BruceBlend), in his Jeep Wrangler's 2.5L 4 cylinder.

Jeep 2.5/4.0/258 engines are known for leaving a little iron and if memory serves, the UOA's weren't too bad.

The Bruceblend had high ZDDP.

Ph:1042 Zn:1151

02 jeep 2.5/5k Bruceblend 0w-10 5100

 

[Jackson_Slugger]

Which is fine, but regardless of the reason it does show that a higher viscosity oil is not in and of itself detrimental to the engine operation. Not saying you’re making that claim but some do.

I don't as I am using a thicker-end 5W-30 (RGT) in my Mercury that calls for 5W-20. But oil viscosity recommended can also be based on availability. I think Gokan showed some of the ridiculously priced oils in Mexico a while back...

 

[Jackson_Slugger]

....
I'm curious how the German Audis and BMW's running the 0w20's are going to hold up. That's more a test than the vast majority of the Japanese and N/A brands running 0w20.

Do these engines have beefy oil coolers?

 

[SZR48207]

What about using a 0w variant to get the best of both worlds? (reduced startup wear, but operating viscosity that is thicker)

My Tacoma calls for 5W30 and I've been thinking about moving to 0W30 once I use up my current collection of oils.

 

[buster]

Do these engines have beefy oil coolers?

Good question, I don't know.

 

[buster]

What about using a 0w variant to get the best of both worlds? (reduced startup wear, but operating viscosity that is thicker)

My Tacoma calls for 5W30 and I've been thinking about moving to 0W30 once I use up my current collection of oils.

Depends on the quality of the VII. Larger spread oils often shear more losing their viscosity easier. IMO Mobil 1's biggest weakness is viscosity control. Not from oxidation as it is extremely oxidation resistant, but shearing.

 

[kschachn]

What about using a 0w variant to get the best of both worlds? (reduced startup wear, but operating viscosity that is thicker)

My Tacoma calls for 5W30 and I've been thinking about moving to 0W30 once I use up my current collection of oils.

Thinner oils do not reduce startup wear, a thinner oil never reduces wear unless the thicker oil is too thick to be pumped. MOFT reduces wear and a thinner oil always has a higher MOFT.

 

[Gene K]

Thinner oils do not reduce startup wear, a thinner oil never reduces wear unless the thicker oil is too thick to be pumped. MOFT reduces wear and a thinner oil always has a higher MOFT.

I'm having a real hard time with that. You won't convince me that points that rely on splash oiling won't get lube faster with a thinner fluid.

Also every bearing dimension, clearance and load has an ideal viscosity. It's not 3.8 cSt to infinity.

 

[JohnnyJohnson]

Do these engines have beefy oil coolers?

But wait a minute the myth is the lighter oils cool so much better why are they even needed?

 

[Jackson_Slugger]

But wait a minute the myth is the lighter oils cool so much better why are they even needed?

What strawman ever said that?

 

[NewtonPulsifer]

I don't as I am using a thicker-end 5W-30 (RGT) in my Mercury that calls for 5W-20. But oil viscosity recommended can also be based on availability. I think Gokan showed some of the ridiculously priced oils in Mexico a while back...

Amazon Prime has been available in Mexico since 2017. Things are much different nowadays in Mexico if you live in a city of 500,000+