5-20 Full Synthetic vs. Conventional 5-30>???

[ULVER]

I have several older cars, that call for 5-30 weight oil. I was thinking of going to a quality 5-20 SYNTHETIC, in hopes of better MPG.

I have had one mechanic tell me that 20-anything is just too thin for brutal south Georgia summers.

I was just curious on thoughts

I would think a full synthetic would always have better protection than "Dino" anything, in any situation.

Secondly, if we are strictly speaking quality synthetics, does a full synthetic 5-30 trump a 5-20

I would think in theory the 30 would offer more protection. While the 20 more MPG.

Since they have been out for a few years now, I assume the synthetic 5-20's aren't compromising THAT much engine life for MPG? Correct?

Thanks for any thoughts...

 

[ARB1977]

I would auto rx even if you already use synthetic, im about to and see if i gain just alittle mpg. Ive used redline and amsoil.

 

[mstrjon32]

This is just my opinion -- but I wouldn't do it. I might be willing to try a 0w-30 in my car that calls for 5w-30, but no way I'd run a 5w-20.

 

[vronline]

Use a 5w-30 synthetic.

 

[JTK]

I'd do it. I have yet to hear of a failure from running a 20wt in a 30wt spec'd engine. I have run 5w-20 where 30wt's were recommended. No issues at all.

Joel

 

[ULVER]

I know our Ford Police Inceptors, used 5-30 for as long as I can remember. Then, a few seasons back, 5-20 became the the suggested weight.

I recall several agencies that ran their cars hard, experienced some engine failures. Ford immediately went to a 5-20 Synthetic-BLEND. Didn't hear anything after that.

I KNOW 5-20 was all about CAFE & MPG. However, leary I night be of it in "dino" formulation, I feel pretty good about a quality, FULL-synthetic 5-20.

More thoughts?

 

[Patman]

Most conventional 5w30s will thin out to a 5w20 anyhow, so starting out with a good quality 5w20 (that doesn't thin out further) is really no different. And another benefit of the 5w20 over the 5w30 is that it's viscosity at 40c is less, so you'll have less wear during the first few minutes of operation, especially in colder weather.

 

[vronline]

He's in Atlanta, so probably not much difference in wear at start-up.

 

[RF Overlord]

Quote:

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I have several older cars, that call for 5-30 weight oil. I was thinking of going to a quality 5-20 SYNTHETIC, in hopes of better MPG.

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Paul, are these older cars all Fords? If so, the Ford 5W-20 TSB will help your decision.

IMHO, I wouldn't put 5W-20 into any car that wasn't on the TSB.

 

[ULVER]

Quote:

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Quote:

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I have several older cars, that call for 5-30 weight oil. I was thinking of going to a quality 5-20 SYNTHETIC, in hopes of better MPG.

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Paul, are these older cars all Fords? If so, the Ford 5W-20 TSB will help your decision.

IMHO, I wouldn't put 5W-20 into any car that wasn't on the TSB.

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Yep, all Fords... Gonna see if the P/I gets any better MPG. Just for jollies...

What I want to know, is if we see the Vics still going another 150K---AFTER---they are taken out of service, and the cabbies get them.

But then again, heaven only knows, what the cab companies throw in the crankcase. Why am I thinking 15-40 something!

 

[Timothy Ferguson]

Use a good Full SYN 5w30. I use 5w30 with no problem even in my 2004 MPV Mazda that specs 5w20. I have a Tacoma now it loves Pennzoil Platinum. No auto RX needed.