Thick oil - Small Engine

OriginHacker21 · Dec 18, 2006

I do believe that a thinner oil = better MPG but not a huge difference.

I recently found out that my co-worker is an automechanic DIY'er. He has a 198x Nissan Pickup with the 2.2L engine with almost *400,000* miles on it.

Anyway, the point is - he is using Castrol 20w50 inside - and has been ever since he bought the thing.

20w50 inside a 2.2L engine for 390,000 miles!

He still reports getting 30+ MPG every day and the truck is running strong. His truck starts well - even in the 30F degree morning of Apple Valley, CA.

After talking with him a little bit he doesn't think 20w50 is that heavy. He has a Prius with 0w20... Still, he says he wouldn't rev his engine real high with that thick of oil because it could damage (he got technical and lost me here) some part of the engine.

I'd have to say that 20w50 for 400k miles is a pretty good track record. My manual book for my 2.2L says using above a 40 weight can damage the engine. Is that true?

What are your comments/opinions?

-Paul

TallPaul · Dec 18, 2006

Well, if he has run 20w50 that long, might as well continue. If he buys a new 4 banger, I would recommend he step down to a 10w40 or 15w40.

Bill in Utah · Dec 18, 2006

Paul, I think the big thing now is that todays oils do SO MUCH better that they do not need to be thick to protect.

5w-20 oils are proving this day in and day out.

I have a 1986 Jetta with 300k on it (any day) and all its ever seen has been 5w30 and 10w30 conventional.

Never a problem starting and still on all OEM parts! Uses very little oil through its 3-4k oci. (like 2-4 oz)

I've run 5w30 through the 120+ degree desert for hours at a time in my Corolla and the used oil analysis come back perfect.

I'm going to run 5w30 year round in it and will be driving it to 300k+. I have no worries.

Take care, Bill

LouDawg · Dec 18, 2006

Quote:

Paul, I think the big thing now is that todays oils do SO MUCH better that they do not need to be thick to protect.

5w-20 oils are proving this day in and day out.

I have a 1986 Jetta with 300k on it (any day) and all its ever seen has been 5w30 and 10w30 conventional.

Never a problem starting and still on all OEM parts! Uses very little oil through its 3-4k oci. (like 2-4 oz)

I've run 5w30 through the 120+ degree desert for hours at a time in my Corolla and the used oil analysis come back perfect.

I'm going to run 5w30 year round in it and will be driving it to 300k+. I have no worries.

Take care, Bill

Bill, you're just so relaxed...nothing ever seems to bother you. I'll bet you've laughed and smiled your way through life.

Good for you!

JohnBrowning · Dec 18, 2006

I work in Heavy Equipment Repair/Salvage for a while. We did repair work and ran a salvage operation as well as a parts operation. Full machine shop. Any ways the owner of the joint had a little 2WD Mitsubishi truck that was used for basic transport and parts truck. It was a little 4 cylinder as well and was clean as could be under the valve cover. It saw 20W50 Cem-Peco dureing the warm months and 10W40 Cem-Peco dureing the cold months and never missed a beat. I think it had almost 400,000 miles when I left. It did use some oil but did not burn any that could be seen from the tail pipe.It had no know or slap. The Harley guys in the Area used to come in dureing the summer to buy 20W50 CemPeco oil from us as they swore it kept their motor's running great even in hot weather. A lot of these Harelys would over heat in parades and stuff with other oils in them.THis was when most Harley guys were afraid to run synthetic in their V-Twin.

Gene K · Dec 18, 2006

I believe the vast majority of current production engines will last within 95% of maximum mileage with anything from 0W-20 to 20W-50. I have seen Toyota 4 cylinders with 500,000 mi that ran anything from 5w30 to 20W-50. I have seen 200,000 mi Ford 4.6L Police Cars that ran 5W-20, 5w30, 10w30, 15w40, and 20W-50. Most engines die of mechanical failure not lubricant failure.

Curious Kid · Dec 18, 2006

Well, it seems the guy knows a few things that help when using a thicker than average oil, like not reving the engine when the oil's cold and especially thick (so the post lead me to believe). I can't say that running such a thick oil helps engine cooling any - greater viscous drag leading to a higher thermal stabilization.

I guess one can get away with using just about any weight, but just for how long, under what operating conditions, etc. There's going to be some trade off but as to what might keep one wondering.

Lonnie · Dec 18, 2006

Could it be that weather and driving habits are more important than viscosity. We could, for better lubrication, have a good driving thread. Good driving costs less that synthetic oil and can work all year-round.

Steelers · Dec 18, 2006

Growing up all we used was 20w-50 in everything, never thought about, never had a problem. Several years into owning a Nissan 4 cylinder truck I casually asked a mechanic about some excessive noise I was getting from the top of the motor. His first question to me was "What weight of oil are you running in this?" When I told him 20w-50 he said way to heavy for such a small motor, back off to a 10w30. At the next change I did and the motor became near silent, smoothed out and pepped up. So while I believe that a heavy oil will not cause an engine to fail it may not be the correct or best weight for the engine either. This experience, though 15 years ago, has lead me to readily accept Ford and Honda's 5w-20 recommendation.

addyguy · Dec 18, 2006

I think part of it as well is just the truck - Nissan and Toyo small trucks seem to be absolutley indestructible. FIL is in the process of getting rid of his 1985 Nissan p/u. Only has 198,000 km's on it, but has lived as hard a life as any - including not having an oil change at all for the last 5+ years. Just topped off when it needs it, but truck still starts and runs fine, and doesn't blow any smoke at all.

Quest · Dec 18, 2006

LOL! Those Harley guys and their air-cooled V-twins.

Probably not getting enough air flow through the cooling fins when they are doing 5 miles/hr in a parade...

OriginHacker21 · Dec 18, 2006

Awesome information. When I used GC 0w30 in my 2.2L - revving to higher RPMs 4k+ seemed a lot more difficult and slower than with Amsoil/Trop Artic 5w30 - though I get bout the same MPG with both.

Either way, yeah - Nissan and Toyota trucks are indestructible. I think California's 115F summers and above freezing winters help a lot too with the guy's use of 20w50. Either way, I think we all agree that it is too heavy and he would benefit from going to a 10w30. I doesn't bother me what he does - just curious to see the truth.

Bill in Utah is the stabilizer

Without him we'd have people using straight 10 weights and straight 30+ weights.

Still, interesting to see a current day manual say that a 40 weight or above could damage the engine. Seems to me that the above posters don't think it will damage the engine - just isn't best for it.

Either way - pretty cool as I didn't think any modern street car could run on a 50 weight these days. Learn something new everyday.

Gene K · Dec 18, 2006

Whether 40 weight or above would damage the engine would depend on the cold cranking temp. If its safe to operate it at 0* to 70*F with 5w30 I certainly would not think 20W-50 operated in 70* to 115*F weather would cause a problem.

There are lots of 1.9L Saturns in the South with 300,000 mi that have run 15w40 HDEO since the warranty ran out as it will often cut consumption by 40-70% over the usual 1 qt / 1000 mi of 5w30.

JHZR2 · Dec 19, 2006

A LOT of little, old BMW engines got LOTS of miles on 20w-50 oil... many old BMW owners still use 20w-50!

A bit more sluggish??? I tried it (havoline 20w-50) my 318i once, and cant say that I noted a difference compared to syn 15w-50 and syn 5w-40 in normal weather.

All the same, I know that given my climate and driving style , a good 40t oil is all that is necessary, and I can optimize upon the chemistry better witha 40wt oil, due to the options, so its what I use.

But there are lots of 200k+ BMWs that have had nothing but 20w-50...

JMH

jsharp · Dec 19, 2006

Lets see. 390K miles using 20W-50 and I'm guessing the engine has "never been touched." And, the guy is getting about 50% better mileage than the likely EPA city estimate for his vehicle. I was going to add something else here but I'm not sure it's required...

moribundman · Dec 19, 2006

Quote:

I do believe that a thinner oil = better MPG but not a huge difference.

In a small four cylinder engine the gains (less power loss and improved gas mileage) from using thinner oil will be much less than, for example, in a larger 6 cylinder engine.

Quattro Pete · Dec 19, 2006

Quote:

In a small four cylinder engine the gains (less power loss and improved gas mileage) from using thinner oil will be much less than, for example, in a larger 6 cylinder engine.

Really? I'd expect it to be just the opposite. Just like in very small engine, turning on the A/C has a bigger effect on gas mileage than turning it on in a big V8, where you will not even notice the increase gas consumption.

As for examples of thick oil in small engines - in my mom's 2-liter turbo, the dealer has been using 10w-60 oil since day 1. The car is 4 years old now... no issues to report.

TallPaul · Dec 19, 2006

Hmmm, maybe it's that absolute gain (comparing all engines) will be smaller, but relative gain (for that particular engine) will be larger.

Whimsey · Dec 19, 2006

Quote:

Quote:

I do believe that a thinner oil = better MPG but not a huge difference.

Click to expand...

In a small four cylinder engine the gains (less power loss and improved gas mileage) from using thinner oil will be much less than, for example, in a larger 6 cylinder engine.

I found that using Syntec 5W-50 in my 2.0L Zetec versus Mobil 1 5w30, the recommended viscosity, caused a noticeable drop in my mpg. It went from averaging 29 mpg down to around 24 mpg or less. Also the seat of the pants power loss was noticeable as well. After two years I went back to Mobil 1 5w30 and my mpg jumped back to the 29 mpg range. And it's noticeably peppier again. "Thickerer ain't always betterer"

. I'm now using Schaeffer's 5w30 Blend. Still the same good mpg and power as the Mobil 1 5w30. Under the valve cover it looks brand new. Not any sign of ANY build-up or discoloration.

Whimsey

Whimsey

moribundman · Dec 19, 2006

Quote:

Quote:

In a small four cylinder engine the gains (less power loss and improved gas mileage) from using thinner oil will be much less than, for example, in a larger 6 cylinder engine.

Click to expand...

Really? I'd expect it to be just the opposite. Just like in very small engine, turning on the A/C has a bigger effect on gas mileage than turning it on in a big V8, where you will not even notice the increase gas consumption.

As for examples of thick oil in small engines - in my mom's 2-liter turbo, the dealer has been using 10w-60 oil since day 1. The car is 4 years old now... no issues to report.

In a small engine oil doesn't have to be pumped long distances through long oil passages. Compared to thin oil, thick oil adds only minor "drag" in a small engine. If I'm wrong, somebody please holler. Some small engines (like in the Trabant) could get away without an oil pump, and they used pretty thick oil, I believe.

Thick oil - Small Engine

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