Is 5W30 OK for Desert Southwest?

I've been using Penzoil 10W30 in my West Texas based 93 Ford Aerostar

3.0L because the manual recommends this for moderate to hot climates. But it says 5W30 is OK for ALL climates.

A few months ago I bought a 2003 Toyota Tacoma 2.4L. Its manual states only 5W30 is recommended, regardless of which region of the country it's in.

The charts I've seen indicate that both 5W30 and 10W30 provide the same performance at the high end of the temperature scale, but 5W30 covers more of the low end.

Can I safely use 5W30 for the Aerostar, too? The van burns about a quart of 10W30 every thousand miles....would it tend to burn more if I switch to 5W30??

Reply to
Josh
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Reply to
JimV

30W means "30 winter," not "30 weight." 30W is the cold weight; 30 is the hot weight.
Reply to
do_not_spam_me

"do_not_spam_me" wrote

Geez...you learn so many new things on the internet.

Ian

Reply to
shiden_kai

actually according a web tutorial on oil it is - The "W" signifies the low-temperature pour character of the oil and also its minimum viscosity at 212 degrees F.

Reply to
Jim

Approximately 11/11/03 19:27, do_not_spam_me uttered for posterity:

For a 5W30 oil, the oil is equivalent to a straight 30 weight at 210 F and to a straight 5 at 0 F, or "winter". More accurately at the higher temp it is too thick to be called a 20 and too thin to be a 40, ditto at low temp is too thick for 0, too thin for 10. A rather coarse set of numbers, not worth much without the service ratings.

Reply to
Lon Stowell

With typical mineral-based oils, 5W30 starts off with a thin base oil and uses a polymer viscosity index improver (VII) to pump maintain a thicker weight in the presence of engine heat. But this stuff is usually very unstable and can break down after just 1,000 miles. By

3,000 miles, many mineral-based 5W30s (even the vaunted Castrol GTX) will have sheared down to a 5W20. Chevron and Pennzoil which use a Group II+ base oil are a little more stable.

Conventional 10W30s start off with a slightly thicker base oil and use less VII to achieve its more modest spread.

With synthetics, all bets are off. Some use esters to drop their lower pumpimg points. Some use thin base oils and VII like their conventional cousins ... just not as much.

All things being equal (and they almost never are) 10W30 is more thermally stable than the same brand of 5W30.

For the best in oil and lubrication discussion:

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--- Bror Jace

Reply to
Bror Jace

Well this sounds good but I have read at least three different SAE papers that tracked oil viscosity as a function of engine hours and in all three papers the viscosity increased with usage - not decreased as you have suggested.

Ed White

Reply to
C. E. White

tracked oil viscosity as a

usage - not decreased as you

Ed, I've seen dozens of lab tests with many of the most common brands of oil. The oil initially thins as the VII is broken down. With some, thinning is observed after only 1,000 miles.

However, once the oil begins to seriously oxidize and loads up with contaminants, it DOES begin to thicken. The viscosity can increase up to and even surpass it's starting weight.

But by that time, it's usually shot and the rate of wear begins to increase dramatically. Oils this badly oxidized need to be drained. Wear is up and sludge is bound to be forming.

Oils should hold their grade throughout the intended use interval. However, with the EPA and API leaning on blenders to increase fuel economy, many are actually DESIGNED to shear down quickly. It seems some are trying to "trick" consumers into using a thinner oil.

--- Bror Jace

Reply to
Bror Jace

Huw, you need to read my last post. It explains what goes on with oils in a little more detail.

They tend to thin, then thicken with every brand being formulated a little differently ... especially the synthetics. Red Line is very shear stable/. Mobil 1 is more stable than it used to be and Royal Purple shears down quite quickly (even their 10W30) ... apparently by design.

Fuel dilution, often played up in the past, is actually very rare in modern automotive engines with a function PCV system and fuel injection. I've seen hundreds of lab reports and I don't think I've seen more than 1 or 2 which had 2% or more fuel present. It flashes off very quickly assuming the engine is regularly brought up to temp.

I wasn't "guessing" at anything.

--- Bror Jace

Reply to
Bror Jace

Most of the results I have seen are from owners of gasoline powered cars and trucks who (generally) take good care of their vehicles. None are on the verge of catastrophic failure. Can you tell me what kind of motor had fuel dilution in excess of 50%? Was it gas or diesel? That is an incredible amount.

Where are you getting this info from? There are literally hundreds of results posted at bobistheoilguy.com and MOST show thinning. It is more common than not in oils which have gone between 3,000 and 7,500+ miles. Dino 5W30s are especially prone to thinning as I have already pointed out. They USUALLY don't make it to 3,000 miles without showing some thinning. Chevron and Pennzoil seem to be two exceptions.

Can you point to some data which shows used oil being measured and found to have NOT thinned in typical applications?

Some dino 5W30s might survive this interval while doing their job, but only through extraordinary measures such as increased oil sump, bypass filtration of auxiliary oil cooling ... or a combination of those things.

--- Bror Jace

Reply to
Bror Jace

It makes sense that the results you were talking about were from a diesel engine. I don't foillow those, only gasoline motors.

You can browse through hundreds of UOAs at this site:

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You'll also see that oil in gas engines initially thins out (often quite quickly) and then thickens only after several thousand miles due to oxidation, etc ...

Take a peek.

--- Bror Jace

Reply to
Bror Jace

On a 93 3 liter AeroStar, I'd run 20W50 in Texas. Heck, I ran it up here in Ontario in the summer - and 10W40 in the winter.(on 1989 and

1990) Never a problem. First one went over 250,000km before the body fell off. Second one had over 240,000 on it when I sold it (had engine replaced due to piston noise under warranty (on 5W30) at about 50,000km) It is still going strong. Neither one EVER used a liter between 5000km (3000mile) oil changes.
Reply to
clare

The only oil I have ever had lose viscosity appreciably in under

5000km is Penzoil. Had the oil changed in the Dodge minivan just before starting a 500 mile round trip delivering some parts. Less than 200 miles from home the oil light came on. Checked the oil level, and it was fine - but it was thin as water. I stopped at a lube shop and had the "piss" drained and Castrol put in. Finished the trip, and another several thousand KM with no problem. My brother had the same problem with a cheap lube-shop oil from ESSO (Exxon) in his Ford. Less than 500 miles, and the oil light would not go out. Checked the oil - it was like water. Changed to a better grade oil and never had the problem again.

Note - in both cases these were Quicky oil change place oil changes - cheapest crap they could get their hands on, IMHO.

Reply to
clare

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