5-20 oil

And today's thicher oils? They have advanced as well.

Yes, but its always best practice to use the *thinnest* oil that provides adequate protection. Too thick and the flow rate and therefore cooling is compromised.

I just checked the repair records of a Voyager that has close to

200,000 miles and a tight 3.0 Liter engine. It's quite tight and not burning oil, touch wood. Turns out the recommended oil is 5W-30 but this car was serviced a lot at a Jiffy Lube that used, instead 10W-30, so one weight heavier than recommended.

I suspect since this car did mostly highway driving on the turnpike that the heavier oil than recommended was most likely a good thing. I'm not using 5W-30 since it's being used mostly for short trips so startup wear and tear is a main concern and it definitely starts up easier with

5W-30.

If I go back to highway driving, I would be tempted to go to 10W-30 which is a tighter oil, fewer grades differential between 10 and 30 compared to 5 and 30. What complicates this for me is that the dealer is using a semi-synthetic of 5W-30 which seems much better than the usual dinosaur oils, a Conoco brand of some type. The car is not using as much oil. Hope it's not hurting the seal and whammo am I going to be suprised in a year or so.

How "thick" is 20W50 oil at 210F? Compared to 5W30 at 32F? A WHOLE lot thinner. And what is "adequate" protection? According to the manufacturer it is good enough to get something like 95% of engines through warranty without detectable damage. To me, adequate protection means good enough to reach 300,000Km or more without detectable damage. Big difference.

Last Aerostar had 240,000KM on the clock when I sold it over 3 years ago - 10W40 and 20W50 exclusively from 45,000km on - (when the engine was changed under warranty for a skuffed piston - 3W30 oil used by original owner when serviced by selling dealer). Still going strong - current owner very happy with it - uses NO oil between changes. Towed 17 foot travel trailer

First Aerostar ran exclusively on 10W40 and 20w50 Castrol GTX - had

240,000 more or less on it when I sold it to a friend - who drove it another 6 years.The body fell off, and the engine was still running strong - burning no oil between changes. Towed 17 foot travel trailer.

Last NewYorker 3.0 had 240,000 KM on it when I sold it last summer. Heads were replaced twice for guide problems (dropped and loose) but with heads replaced used no oil between changes - run exclusively on

10W40 and 20W50 oil.

Last LeBaron T&C 2.6 (1985) was purchased with a blown engine (countershafts seized - stripped crank sprocket and spun main bearing) at 99,000Km.Was run on 10W30 oil. I rebuilt the engine, and ran 10W40 and 20W50 oil in it 'till the body fell off (aprox 225,000Km IIRC). I sold the engine to another LeBaron owner in 1994 and it was still on the road last year, running strong with no timing chain noises.

My 1981 Tercel, which I serviced from new with 10W40 and 20W50 was traded in at just under 200,000KM - when I bought it with some minor body damage. I sold it with almost 300,000KM on it - and the new owner was still driving it a year after the speedo quit at 460,000KM, more or less. He said it was the best vehicle he had ever owned, other than the body which eventually just rotted away around him. Never added oil between changes. HE NEVER TOUCHED THE ENGINE EXCEPT TO REPLACE ONE SET OF POINTS AND ADJUST THE VALVES.

10W40 and 20W50 worked fine for me, and for my customers.

Don't know what oil was used in my daughter's 96 Neon before she got it - but it consistently uses 1 - 1 1/2 liters of oil between changes at 165,000 Km. Doesnt much matter what oil I put in it.

I've never had viscosity change problems with the 10W40 and 20W50 oils I've used - but virtually never went over 6000Km on an oil change.

I HAVE had viscosity loss problems with 5W30 (Penzoil) in a company owned Dodge minivan less than 100 miles after the oil change - the oil light came on while on the highway - the dipstick showed full - so I had the oil changed AGAIN and put "real oil" in it (Castrol GTX) and the light went out. The tech who changed the oil said what came out was thin as kerosene.

You can buy your brand new vehicles, and service them by the book for

2 years or so, and trade them in. I'll buy said low mileage used car, put whatever oil I please in it, and drive it another 10 years or so (till the body or the wheels fall off, or I just get tired of driving the same old car) and reluctantly send the still running engine to the scrap-yard if I can't find somebody who wants to buy it cheap.

Something like 25 or 26 vehicles now, and I've never blown an engine. Only sold one with less than 160,000Km (100,000 miles) on it.

That's interesting and sort of my experience. I remember one car, hundreds and hundreds of thousands of miles, /6. When it got bad, I used to buy that racing oil, Kendall SAE 50. Not suppoed to work but it sure did bring up the compression. What a Plymouth!

But I gather you're talking mostly about highway miles at faster speeds, like 60 mph and better, yes? I'm starting to favor semi-synthetic 5W-30 because it's not getting burned up as fast and I'm doing a lot of short hops which means starting the engine is my main concern.

But in the past, I used to go with 20W-50, 10W-40, and so on, even SAE

30, kind of mix my own.

Come to think of it, I've had cars where the engine was still good, just the rest of the car was self-destructing. Boy is that annoying.

Thickness or viscosity is fairly irrelevant, unless an oil becomes to thick to pump or so thin that the oil pump can't maintain enough pressure to deliver the oil uniformly throughout the engine. Film strength is what protects from metal-to-metal contact, and film strength has little correlation to viscosity. If thickness were so important, we'd all run 90-weight oil.

And lots of wasted fuel. No car I've owned has ever used thicker than

10w30 in Central Texas, and the newest one has 230,000 miles on the original un-opened engine, and doesn't burn oil between changes.

My newest car (mentioned above, wife's daily driver) is a 1993. My second newest car (440,000 miles as of last Thursday, my daily driver) is a 1973. Both of those have lived on 10w30 their whole lives. I'm

*definitely* not a "trade it every two years" kind of driver, which is exactly why I don't run crap like 20w50 and 10w40 oils, which are more prone to putting the oil filter into bypass mode, uneven oil distibution, poorer heat dissipation, dry starts, and lower volume flow through the bearings than thinner oils.

To be fair, I also do not run things like the new 0w30 oils either, because I'm a firm believer in using the narrowest viscosity span oils that I can, since fewer viscosity modifiers have to be used in the oil formulation.

You are right - to a point. Oil provides a hydrodynamic "wedge" that is most drfinitely viscosity related. This is more important in non-pressurized systems - the same systems where higher viscosity can be a problem because the oil cannot flow into the bearing surface as well. Where higher viscosity oils ARE a definite advantage is on engines with timing CHAINS instead of belts. The longer the chain and the more tensioners, the more effect viscosity has on life. A typical example is the 2.6 Mitsubishi. 2 chains - one for the cam and one for the balance shafts and oil pump. The second chain is roughly 6 feet long. Run a 2.6 of 5W30 (or 10W30) and use the "normal" change interval and you can be guaranteed a noizy engine before 80,000Km (50,000 miles). Use either heavier oil or the "extreme" oil change schedule, and you will stretch the life to something over 120,000Km. Do both, and the chains and tensioners just keep going, and going, and going.

On Toyota "M" series engines (early Mk2 and crown, Supra and Cressida engines) we ran into the same issues. Changed lots of chains and tensioners on vehicles I didn't service - not even ONE on those serviced to my recommendation. Same with the 8R, 18R, 18RC series engines on the early Corona, Celica and Hilux. When I worked for the dealership in the late sixties / early seventies we used the recommended (at that time) 1W30 oil. I replaced several timing chains and tensioners on R and M series engines. In Africa, nobody would THINK of using less than a 10W40, or straight

30 weight oil in those engines - and unless you knocked a hole in the oil pan the engines were pretty well bulletproof (not like the 3R/5r Corona engines) That's when I started looking seriously at heavier oils for "normal " use. I had always used the heavier oils in my higher mileage used cars previously (20W50 in the slant six Darts and Valiants, as well as the 850 Mini (which ran straight 50 before rebuilding at about 200,000 miles) In the Mini, the engine oil was also the tranny oil, and the diff oil.

Camshaft wear is another place where heavier oils can and do reduce wear.Chevy 307 (in particular, but other SBCs of the same vintage, generally)engines run on 5W30 oil had LOTS of problems with cam lobes going round. Those run on heavier oil tended to last longer before the inevitable happened. Same with the early Pinto/Bobcat/Mustang 2 2200 and 2300 engines.

I don't have an axe to grind here - use whatever oil you like, and be willing to live with the consequenses. I'll use the heavier, wide range multigrades and change oil oftener than many of you guys would say is required. The oil isn't wasted, as it goes to be recycled. It costs me a bit more, but like Fram used to say in days of old- "You can pay me now, or you can pay me later"

Assuming you mean 90 wt. gear oil, (and you may know this already) most people are not aware that 90 wt. gear oil is approximately the viscosity of 10W40 motor oil (two different systems to specify motor oil and gear oil viscosities). (You can always claim you meant 90 wt. motor oil, and who could argue with you.)

Perhpas (or perhaps not) you would agree that on an engine with a lot of miles (like, say, 150+k), you would be wise to bump the viscosity up a notch so the oil pump wear is compensated for a bit (to help it achieve pressure), and the clearances (leaking gaps) in the upstream bearings don't dissipate all the flow and pressure and starve the downstream bearings?

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

Thanks for that info. which I didn't know. Good to know for my 2.7L (with timing chain) - glad I decided to go with slightly heavier oil than recommended but for other reasons.

I know that GM was known for years for their nitrided cams wearing like butter once the very then nitride layer wore thru - was that the problem there? Sometimes a special cause like that forces you to compromise decisions like oil weight - IOW, if the cams were not a special problem, perhaps (perhaps not) things would have been better overall to go with slightly thinner oil.

My philosophy exactly.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

"...very THIN nitride layer..."

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

This was a regular, dinosaur oil, this 1W30? Do you think using a semi-synthetic or even today's dinosaur with the latest ratings, SM?, would give the same dismal results, in your opinion? That's an awfully wide band to maintain more than 25 years ago, if I understood you correctly. I am not surprised that it was a disaster. I talked with another shop manager, and he said the same thing. Just keep the grades narrow and he even thought

10W-40 was too wide a separation.

These were Toyota LandCrusiers or what engines? Is it still this way? It's pretty hot there in places and they go long distances, so stop and go is not their concern, I would guess.

I'm using a 5W30 oil, semi-synthetic, ConocoPhillips/Kendall on an engine that has almost 200,000 miles, that is, ~320,000 kilometers. Original engine presumably, at least for the last 130,000 miles.

So far, engine is fine. Hear valve tapping for about 1 minute, sometimesl on startup and need an oxygen sensor replaced but the timing belt looks fine. I preferred a heavier 10W-30 with fewer separations, just what, two grades here 10 to 30 or three grades all told. The car has generally gotten a 10W-30 oil, 1994 Plymouth 3.0L Mitsubishi Voyager. But it's getting older. I was startled to find, unless I am wrong, this car's dipstick is notoriously difficult to read, the 5W-30 is not being consumed as much as the 10W-30. In 2,000 miles, I don't think I really even needed to add a quart. With 10W-30, I usually added one quart every 1500 miles. Oil is changed every 3000 miles.

Do you have any thoughts in this case, on 5W-30 semi-synthetic versus dinosaur 10W-30? The dinosaur oil has often the higher grade, though, SM, versus, SL for the semi-synthetic oils, when I look at some of them in the stores.

I'm thinking about this since I used to consider that

10W-30 was too light. I did not really like 10W-40 because it was four grades combined, but the oils are getting better I'm told.

Something tells me he meant 10W-30.

It's impossible to say anything about a commercial semi-synthetic since you don't know the mix of synth to non-synth - which is why I refuse to buy those. Better you mix your own so you know technically what you've got and what you're paying for - there are those experts who claim that there are some synergistic benefits of a blend over straight synth. To me, it would be just way too tempting for the MBA's to have them sell you 15 synth/85 non-synth and charge you an 85 synth/15 non-synth price.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

Again, I'd say that there are other ways to solve those problems than increasing viscosity (like don't buy Shove-a-lot engines... ;-) Seriously, in the case of timing chains, distributor drive gears, gear driven oil pumps, and slider-type camshafts, the single most critical component of the oil chemistry is zinc content. A thin oil with a big dose of ZDDP additive would, IMO, be far better than a thick oil with less ZDDP. Thats exactly the reason I like the new Mobil "extended life" oils- they have higher loadings of ZDDP and other additives than the standard Mobil 1. It means they don't get the latest API rating because the API wants oil makers to cut back on those additives (because they can potentially damage catalysts and they aren't needed as much in new roller-cam engines with timing belts or roller timing chains and no gear drives) but it makes them a great oil for older engines with gears, non-roller timing chains, and slider cams.

Lets say 250k.... I've yet to see many reasonably maintained Mopar engines that have lost much oil pressure at only 150k on 10w30.

As a last-ditch effort, yeah. But the best tool to decide that is an oil pressure guage- if the oil pump can still deliver 30-40 psi on the thinner oil, then nothing's starving (depending on engine design, that's a good number for Mopar v8s). The problem with going too thick is that the drag of the oil galleries may mean that the thick oil flows very poorly to such 'last-in-line' items like the rocker arms and valve tips (again talking Mopar oiling systems here). A thinner oil may show less pressure on the guage, but still gets distributed more evenly as long as you're not talking REALLY low pressures like 10-20 PSI at cruising speed.

Sorry - finger slipped. 10W30. We used the top line Valvoline as well as Castrol

Yes - I strongly suspect it would, particularly with the low zinc formulations.

It IS too wide a separation for extended drain intervals - which I dissagree with on principal with ANY oil. For 5000Km (3000m) intervals, using a QUALITY oil, the whole long-chain hydrocarbon shear phenomenon is a red herring. I've never seen it happen. Oil is more likely, in today's engines, to thicken from heat than to loose viscosity from shear in that period of useage. Witness the problems with "coking" on some Chrysler, some Toyota, and several other brands of engines.

Nope - not the Cruisrs. The "F" engine in the cruiser is, for all intents and purposes, a metric version of the Chevy Econoflame six. Geared cam IIRC.

The vast majority of miles put on the average private car in Africa is put on slowly and painfully, mile at a time. The roads, generally, do not encourage high speed driving - although I've driven on roads where anything between 30 and 60MPH was virtually impossible. Drive under thirty on the "roller-coaster" or over 60 on the "pogo-stick" - hit one bump and miss the next 10 or so. Anything in between was like riding a jack-hammer. There are long distances between major centers - but generally the distances are broken up by many small towns and villages - with the ever present goats, cattle, guineas,pigs etc - not to mention wildlife if you are in the south/east.

A high quality synthetic or blend does not thin out as much as your regular "jungle juice" and provides less friction - might work as well as 10W40

And with a BELT, the oil has no bearing on timing component life.

The "jungle juice" tends to boil off faster than synthetic based oils. Can't compare oil consumption between a synth blend 5W30 and a regular

10W30 and conclude that the car burns less "light" oil than "heavy"

Yes and no. On a high mileage 3.0 Mitsu, with 3000 mile change intervals, I'd use 10W40, and even 20W50 in the heat we've been experiencing up here in Ontario this year. Or go with something like Rotella T 15W40 from Shell.

If you see EXTREME cold in the winter, a synthetic (blend) is possibly worth while on that engine for better cold flow, but a full synthetic is liable to cause you some un-necessary oil leaks. Those Mitsu engines are hard enough to keep dry on the outside with regular oil.

I've read that the problems with fully synthetic oil leaking were only a problem with early synthetics -- that they lacked the chemicals that cause the seals to swell and hence keep the oil in -- and that this problem no longer exists, since the formulations have changed.

I recall reading that full synthetic are more prone to piston scuffing than a blend.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my adddress with the letter 'x')

I recall reading some things about tooth fairies, winged horses with horns, and Paul Bunyan too.

:-)

On a new engine that may be true - but when the rubber is already hard and it's just varnish and sludge keeping the oil in, it's a totally different story. Synth will get out where regular oil has stayed for years.