Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Fewer "mass polluters" from oil burning, etc. on the road or so it seems. I am glad but hy is this?

I have noticed fewer mass polluting vehicles on the road lately and am curious as to why. Getting behind a nasty oil burning smoker was common and I would get behind one at least once per day, often more. These always seemed to be a Chrysler product of some type, usually an older minivan with the Mitsubishi engine that was notorious for oil burning. Although I am happy not to get behind cars like this, I am curious as to why you simply do not see vehicles like this nearly as much as in the past. I live in a rural part of Missouri where we don’t have emissions inspections so that isn’t why.

Here are some reasons I have heard.

  1. Cash for clunkers got a lot of these junkers off the road.
  2. Police, etc. ticket drivers of these vehicles enough that it is best to either junk or repair the car.
  3. Engines are built better and tend to last longer, even with less than ideal maintenance, so some other major failure or accident takes the car off the road before the engine has a chance to really begin burning oil.
  4. Newer cars have catalytic converters that are better able to convert this smoke to cleaner exhaust.

Another theory that I have but have never heard is that because cars have so many sensors and everything is computerized that semi-modern to modern cars will simply run terrible or not at all because all the O2 sensors, EGR, etc. become so fouled with carbon from all the oil burning in a very short time.

I know that some of the lower income people around here haven’t just decided to start maintaining their cars better so why is this the case? I talked to a used car dealer once who sold mostly $1500 or less vehicles. Most of these were the result of his primary business being a towing company. He would get called by the authorities to tow in abandoned vehicles. These cars are almost all 10 year or older and have something wrong with them so the owner doesn’t pay the tow fee and he applies for an abandoned vehicle title after many months. He then repairs the usually minor failure and puts the car up for sale. He told me that he always puts a quality synthetic oil in these types of vehicles because this is usually the last oil change these kinds of cars will ever get. He says most engines will run at least a year without an oil change and the owner won’t blame him for selling them a bad vehicle by the time the engine fails due to owner neglect.

Just my 2 cents and I could be dead wrong but I lay it off on two things.
One would be converters catching a lot of the burnt oil and two (the main one IMO) is modern era engines holding up better due to the phaseout of leaded gasoline.

There’s a world of difference when examining a torn down engine in the old days compared to the teardown of a modern era unleaded gasoline engine.
An old leaded gas engine often had heavy deposits on the piston tops, valve heads, etc and a modern era unleaded gasoline engine may still be fairly clean even at twice the mileage.

I agree it’s a number of things; better engines, much better oils, CD ignition with more reliable spark, no-lead gas, much better spark plugs and very lean mixture control.

In other words, engines last a lot longer and we now have many engines outlasting the transmission and body. The number of engine rebuilding shops has sharply decreased over the last 35 years.

The improvement in automobile emissions control and engine life seems to be due to precise fuel metering by feedback fuel injection.

  1. No, not enough of the smokers got junked but it did raise the price of used cars
  2. Never happens in my state, ever. No smog test at all (when we did have smog checks, those smokers where given a “pass” because they were owned by low income folks)
  3. Absolutely yes, plus all the Mitsu Chryslers eventually died off (like the dinosaurs)
  4. Nope, cats die when loaded with hydrocarbons from oil burning

I’d say that the gross polluters finally just died off. Engines in modern cars are just that good. Better than some of the things attached to them like transmissions and such. Just be happy and breath easier!

I think engines have improved. Through the early 1960s, Consumer Reports in its road tests of cars would give the oil consumption of cars tested in miles per quart after break-in. As I remember, the Plymouth Valiant tested in the early 1960s went 450 miles per quart of oil.

My first car, a 1947 Pontiac purchased in late 1961 went about 250 miles per quart of oil. I paid $75 for the car from the local Buick dealer. I imagine today a car like that would probably be junked by the dealer. There were no pollution tests in those days.

The only oil burning engine at our house is my lawnmower that I purchased in 1992. I installed a new short block due to oil burning 10 years ago. It’s now using oil again. The mower is great for mulching leaves which is why I did the short block. For a while, I would only see blue smoke when I hit a thick stand of grass and the governor opened the throttle. Now, I detect blue smoke all the time that the engine is running.

On the highway today, I spied a HUGE plume of white smoke coming from the tractor of an 18-wheeler. This guy was virtually fogging the highway with the white smoke from his exhaust stack, and I have to assume that this was a head gasket problem.

Anyway…my point is that almost all of the vehicles that I encounter on the road nowadays emit only a small fraction of the pollutants that cars emitted as recently as the '70s, and that is a good thing. It seems that only the rare vehicle with a serious engine-related issue is a major polluter nowadays…at least in comparison with those of my youth.

Malleable iron piston rings help too. The old ones were hard and had to wear a bit to break in. They kept wearing and eventually stopped working so well. The new rings don’t push against the cylinder walls as hard so they can last a long time. Better oil keeps everything from gumming up.

Even if you live in a state without smog testing you’re surrounded by cars engineered for the states that do. Be thankful someone insisted on breathable air.

Engines are a little better than they were. Usually the only oil burners I see are foreign cars that some teen has “riced up” and beat the snot out of, or cars generally owned by barely conscious people that drive about 45 on the highway with a death grip on the steering wheel. It seems obvious to me that these cars rarely get oil changes and are never driven hard enough to keep the rings seated and burn the crud out of them.

In addition to the visible pollution, we should all be glad the invisible pollution that creates “smog” is being cleaned up from our car’s emissions.

Besides the Mitsubishi motors mentioned, early Hondas, GM and Ford straight-6 motors with high mileage, and old Ford 2.3 liter 4 bangers come to mind as oil burners. (though with the 2.3 it was often the rear main seal leaking oil onto the exhaust) The worst one I saw in quite a while was a Geo Metro that could have been used as a mosquito fogger or possibly had been converted to run on smoke grenades…

I am sure that better materials and tighter tolerances are a big part of why car emissions are so much better and oil use isn’t as big of an issue. I know oils have also improved and I pretty much run synthetics in everything I own, including the lawn mower. I run a 5W40 diesel spec oil in lawn equipment and have noticed a definite drop in oil consumption with this oil.

The Geo Metro comment is a good one. I happen to own a 1994 Geo Metro with the 1.0L 3 cylinder engine. The first engine I had in this car did just that. It ran well without smoke about 98% of the time. The other 2% of the time was a different story. Problems usually began on the highway at high speeds. When hitting a strong headwind or climbing a long uphill grade in a high gear, it appears that the load on the engine contributed to excessive blowby of the worn piston rings. This would pressurize the crankcase and prevent oil in the valve cover from draining back to the sump. The valve cover would eventually fill with oil until it would overflow into the breather where oil would be poured directly into the throttle body and burned in the engine. We are talking about spoonfuls to a cup or more of oil at a time being pumped into the engine. You didn’t happen to see this car in Missouri on I-44 did you?

I tried a few engine flushes and oil additives to maybe loosen up a stuck ring or similar but nothing helped. It seemed that the goo I was flushing out was holding the engine together and the smoking problems became worse. I mean people were honking and pulling over behind me on the interstate highway. I was burning AT LEAST 1 quart every 100 miles. The comment about smoke grenades is no exaggeration! Research indicated this is pretty common with these engines when they are worn out as the PCV system in these engines isn’t real strong. The term used for this is an oil fart in the Geo Metro groups.

I found a good used engine from another Metro that had rusted out and swapped it into my car. I put a car jack under the oil pan with a block of wood, unbolted the engine, disconnected the lines and harnesses, and simply lifted the engine in and out of the bay by hand. The little engine doesn’t use any oil on the stick between changes and I have been running European spec synthetic oil which these are supposed to love. The little car now runs great and gets 55mpg which is why I got it.

One of the main problems with the Metro is that is was a cheap car from the start. The people who bought them tended not to treat them well or take care of the regular maintenance. They will run forever with good oil but are not forgiving at all to neglect. Stuck rings are pretty commonplace. It is rare to find one with both a solid engine and body.

My ‘smoker’ story was with my '84 Jeep Cherokee. In '92 I was waiting at the drive through, wondering who was driving the junker putting out all the smoke…oops. Turned out to be something in the EGR/PCV system (I don’t remember which). And that Jeep still had a carb.

Haven’t had that happen in any newer cars.

A clogged PCV can cause oil burning amongst other problems. I pretty much consider this standard maintenance every 100k miles or every time I purchase a used car. It is a $5 part that takes 5 minutes to install although I have heard some horror stories of it now being integrated in the valve cover or similar. Not changing the oil often enough or using something that turns to sludge in your engine will gum up the PCV and do this. Short drives where the engine cannot fully warm up are also terrible for this.

I knew several people who owned various Chrysler products with the 2.7L engine. It seemed that most of these burned oil like mad and then threw a rod through the block if the owner kept them long enough. I understand there were lots of design defects in this engine. For example, the water pumps tended to leak internally to the engine when they were worn out instead of external where you could visibly see the problem.

Older Chrysler minivans with the Mitsubishi seem to all burn oil, my dad’s 1988 smokes quite a bit but it’s been off the road for years now (waiting for him to either junk it or put it back on craigslist)

One reason is I think today’s better oils hold up better with abuse, so negligent owners can go further before things get gross.

One thing I remember about automobile engines up until about 1962 was the road draft tube that ventilated the crankcase. The blowby from the engine was vented this way. You could see and smell the oil burning in engines of this time period as the engine aged. Positive crankcase ventilation was a great thing when it was added to cars.

Yep, just the market share shift of the ones being entered into service vs the ones being retired.

We see this same indicator of market share shift in our parts inventory too.

one example is the sizes of tires in stock. I’ve been here since 79 when dang near everything had 15s. Cars, trucks . Then the norm became 16s and now it seems we don’t even stock a good ol’ 235/75r15 at all any more. Most of the pickups are on 17 and 18s now from the factory.

The one and only smoker I had was a 1948 Dodge, which I bought for $125 when in college in 1958. It did not smoke when I bought it, probably because some thick sticky stuff was poured in the engine. As I drove it more it started smoking and I had to add oil regularly. It mercifully died in a collision.