Why your engine uses, burns or leaks oil AND what to do about it

Hey folks, welcome to another edition of My Car Guru.

I got my Piccolino's wet just now.

Those are my favorite shoes, my favorite brand of shoes.

If you haven't tried on a pair of Piccolino's, you haven't lived.

And well, you've probably lived, but you haven't lived as comfortably as I'm living right now

in my Piccolino's.

But yeah, they're leather and they got wet while I was washing my 1934 Ford.

And why was I washing it?

Well, because it had been left in the service drive when we were doing all of our teen driving experiences last week.

And it got covered with dust.

And so I wasn't happy with it.

You ever wash a car that's a convertible and has no windows?

That takes some skill, especially when the leather is Lebaron Bonnie leather, very high dollar, as we say around here, high dollar leather, expensive leather.

And so I have a technique for doing that, which we won't get into on this particular program because you probably won't be doing that.

What we are going to get into, though, is a little technical, and it's about your engine.

Yes, we're going to talk about why engines use oil.

They're not supposed to.

Many of them don't.

I remember when the Mazda RX-7, you remember that car?

Really cool little sports car.

You know what was unique about it?

That's right.

It had a rotary engine, which originally was called a Wankel engine, W-A-N-K-E-L.

Why was it called a Wankel?

Because the guy who invented it's last name was, that's right, Wankel.

So the Wankel engine was designed to use oil, just a little bit, more so than a regular piston engine.

Both of them are internal combustion engines, but the Wankel was different.

It had rotors, basically only had three moving parts, two rotors that spun around and the rotor shaft.

That was it. Very simple.

That was one of the sales points of the rotary engine.

The negative was that it used about a quart of oil every thousand miles.

I remember when we first started selling rotary engines.

When we became the Mazda dealer in 1977, we still had the RX-4, the RX-3.

I think we had a rotary engine truck, but they were notorious for two things.

Terrible gas mileage and using oil, but they were fun.

They were cool. They sounded really neat.

And so Mazda decided to come out with a rotary engine sports car, and it was a huge success, the Mazda RX-7.

But this oil usage thing was a problem.

Now if you fast forward to today, if you were to drive into my service department and you were in a modern car

and you said, hey, Lenny, my car's using oil, I would say how much is it using?

And you would say, well, approximately, and I would just stop you right there.

I said, let's do an oil consumption test.

So what we'll do is we'll change the oil right now today.

Make sure that it's right on the full mark.

And then we're going to have you drive 500 miles or less.

It depends on how much oil it's using.

But let's say they say it's using a quart every, well, between oil changes, like between every 5,000 miles.

We'll say, okay, let's do an oil consumption test, drive 1,000 miles and then bring it back and let's see what it's doing.

And if it is using a little bit, let's say it's down half a quart.

Well then, if it's a new vehicle, you have to call the manufacturer, the service representative and say, hey, we've got a customer here that has a whatever.

Let's say it's an F-150, although they don't use oil.

But they could, you know, anything's capable of having an oil consumption problem.

And we just did an oil consumption test and it used half a quart in 1,000 miles.

And he may say, that's normal.

That's within the normal range.

And we say, what?

And they say, yes.

Because really what they say matters the most because they're the ones that have to pay for the repair if we have to do something to it.

Now the person who owns the vehicle said, well, my last F-150 didn't use any oil.

And we say, well, yeah, but the manufacturer says that is within factory specifications.

And he says, well, I'm not happy with that.

And then he goes and trades it for a Chevrolet.

And it may end up doing the same thing.

But what causes this oil usage?

Well, every engine is different, just like every person is different.

And there's only a few places in the engine that oil is supposed to be.

And one is in the crank case and the other is in the top of the engine where the valve train is.

If oil gets into the combustion chamber where, you know, where the pistons are going up and down inside the cylinder.

If it gets inside there, it's going to burn and it's going to come out the tailpipe and oil is going to disappear.

What makes oil get into the combustion chamber?

Well, typically it can come from several places.

The most common, see, the valves are in the top of the engine.

Okay, so the valves open and close and what they do is they let fresh air into the combustion chamber.

And that when that valve closes, there's an explosion inside the cylinder of air and gas.

And then when the piston goes back down and comes back up, the exhaust valve opens and there goes all of that nasty stuff through the tailpipe, supposedly.

So all those valves in the top of the engine have seals.

Not that kind of seal, but, you know, a rubber seal.

And they can then take, you know, an intense heat, but they do wear out over time and they can just break apart.

And that allows oil to dump into the combustion chamber when the valve opens up.

Not good.

If that happens, you're going to see blue smoke coming out of your tailpipe.

Usually when the vehicle's cold, that's when you'll see valve stem oil smoke.

Now, the other place is in the bottom of the engine where the crankcase and, you know, the pistons are going up and down inside the cylinder.

Sometimes you can have oil go past the oil rings that are around the piston.

These are just, you know, it's a circular ring, typically has a little split on it so you can fit it on the piston.

And there's multiple rings.

And those rings are designed to basically seal the combustion chamber so that you can get an explosion that will push the piston back down and ultimately turn the crankshaft, which makes the car go down the road.

Well, there's a little bit more to that story as well.

But if these rings that surround the piston that are going up and down inside the cylinder, if they get worn or one of them breaks, then oil can go where it's not supposed to go into the combustion chamber.

So all of this combustion is taking place above the piston and below the valves.

And so if oil gets in there and it's leaking through the rings, typically you're going to see a bunch of blue smoke coming out the tailpipe when you're going down the road after the vehicle is warmed up.

This is where a lot of oil can go.

Now, where else can it go?

My goodness.

It can go in a bunch of places.

That's typically how oil gets into the combustion chamber, but there are other ways.

But do you check your oil?

I showed these teenagers not too long ago at the teen driving experience how to check their oil.

They had no clue.

Most of them had never seen an oil dipstick.

Couldn't find it if they had to.

But they can now.

That's why people come to these things.

People were asking me, how did the teen driver experience go?

And I said, it went fantastic.

But they were all kind of like prisoners in a prison.

They weren't there because they wanted to be.

They were there because their parents insisted that they come.

But when they left, they all left with a smile on their face and they had learned something.

Even the guys who got out their cell phones in the middle of my presentation.

I called them out because that's just what I do.

And they put the phones up and then smiled at me.

And they were so tickled that they know how to check their oil.

But when you don't check your oil, you don't know if your car is using oil.

If it uses enough and it goes down, down, down, then your engine will lock up.

And you'll be out of, well, you won't be able to get around.

Because your car is down and you can't afford to put a new engine in it.

Check your oil.

But where does oil go other than getting burned in the combustion chamber?

Leaks.

Where can it leak from, Lenny?

I'll tell you here in just a minute.

All right, I am back.

So can oil disappear in other ways other than being burned in the engine, in the combustion process?

Yes, it can.

It can leak out.

We all know that.

We see the spots on the garage floor or in the driveway.

Should we be concerned?

Yes, we should be.

We need to find out where it's coming from.

Now, what if we just got an oil change?

And it didn't leak before.

It's leaking now.

Well, it could be that they stripped out your oil drain plug.

Shame on them, but it happens.

These exuberant teenagers that were flipping hamburgers before they go to work at the Jiffy Lube place,

they're paid by how many cars they can process, how fast, so they'll strip out a few plugs and they won't worry about it.

But you will.

Another thing they do is they spill oil on your valve covers when they're putting fresh oil in.

And so, whoops, you know, they don't do a real good cleanup job, so they put the oil cap back on.

Check your oil dipstick.

Yeah, it's got, it's full.

And then as you drive the thing, you start smelling that burning oil.

And when you get it home, you see a few drips.

That is a less serious situation, but still an annoyance.

We don't like annoyances.

We have too many of those in life as it is.

So the oil pan, that's where all the oil goes when you go to sleep.

All the oil drains back down into the pan.

And that oil needs to get to the top of the engine, and it does that with an oil pump, when you start your vehicle,

so that all the moving parts inside your engine can be lubricated.

That's why I say you need to just kind of sit in your driveway for about at least 30 seconds to a minute.

Modern cars don't need a long warm-up time, but 30 seconds is not very long,

and you just want to make sure that the upper end of your engine, where all the overhead camshafts and valves and all that stuff is,

it probably still has a little bit of oil in it, or on them, but I really wouldn't want to risk that.

So let your car warm up.

But the valve cover gasket, once it's all under pressure inside your system, they can leak.

That's the gasket right under the valve cover.

Those tend to leak after about 30,000 miles. They start dripping.

And sometimes you can just put a wrench on it and retighten the bolts that go around there, but sometimes that gasket has to be replaced.

And a real leaky valve cover can get oil all over your engine.

And then as it drips down on the hot parts of the engine, which about all of it's hot, then you'll have an oil smell, which is not pleasant.

The rear main seal, that's the seal at the very back of the engine, that can leak.

That's more serious, and that's very expensive because the transmission has to be removed in order to get to the rear main oil seal.

And so, like I say, that's not one that you want, but it has to be fixed.

The oil filter seal.

This can also happen at the Jiffy Lube place, if they can strip out your drain plug.

I've got to stop saying Jiffy Lube is my example.

Let's fast lube the quick places.

So, if they don't get your oil filter on there nice and snugly, then there's a little rubber gasket that has to be smashed.

They can either over tighten it or under tighten it, and it will leak.

And so, most of these, like I say, this will manifest itself after you've had your oil changed.

And it doesn't just happen at the fast lube places.

It can happen at a car dealership as well.

What other seals?

A stripped drain plug already said that timing cover gasket, that's on the front of the engine, and it has oil behind it, and over time it can leak.

Crankshaft seal, head gaskets can blow.

The head is considered where the valves are.

So, that's the upper part of the engine, and it connects to the lower part of the engine, which is called the engine block.

So, you have the head, and you have the block.

There's a gasket in between.

Very important gasket.

If you blow your head gasket, have you ever said that just as a kind of a saying about somebody getting mad?

Boy, he blew his head gasket.

That's where that phrase came from, because it's an important gasket.

And when it blows, it can blow coolant, and it can blow out, or it can blow in.

That coolant can mix with oil.

Not good.

Yeah, you don't want coolant in your oil system, and you don't want oil in your coolant system.

You didn't know that, did you?

Let's see what else.

Oil cooler lines.

Okay, what are oil coolers?

Well, that's not in a lot of vehicles.

You see that maybe in real high-end sports cars?

Sometimes they want to make sure that the oil stays at certain temperatures, so they'll take it out of the engine through a hose

and put it in something that looks like a little miniature radiator, and then they'll send it back to the engine.

It's all under pressure, so it's moving.

And so sometimes those lines can leak.

Sometimes an oil pressure is sending units, so that sends a signal basically to a gauge on your dash or to a warning light

that says, hey, oil pressure has gone down too much, and those have seals around them as well.

Even your dipstick tube has a seal around it.

That can leak.

If you've got an older car and an older engine, it's going to leak somewhere,

because a lot of the aftermarket gaskets and seals that they make, they're just not as good as the original ones that came from the factory,

and so they end up failing regularly.

Everything I have, every old car I have leaks oil.

My wife has just gotten used to it.

She accepts it.

It's something you just have to accept.

I wish she would accept the fact that sometimes I fail to empty the dishwasher or get the garbage can to the road.

She will never accept either one of those.

But she can tolerate a few oil leaks in my garage, or our garage.

Oh yeah, there's one more thing that can cause oil leaks.

And that's the PCV valve, and hold on for this one.

I'll be right back.

Are you still holding on?

Okay.

PCV.

Lenny, what's that stand for?

Positive.

Crankcase ventilation.

So this was a brilliant invention.

Because in the process of creating power for a vehicle to move down the road,

inside the engine, you know, we got all this oil, we got gasoline mixing with air,

all of this activity is going on.

There is some residual stuff that finds its way around the engine.

It moves past the pistons.

These are unburned gases, basically.

And they will move past the pistons through the rings and get into the crankcase where they're not supposed to be.

Well, there's positive pressure inside that engine that will force it up into something called the positive crankcase ventilation valve.

PCV valve.

I bet some technician has said to you at one time or another,

hey, you need to replace your PCV valve.

And you said, whatever.

How much is it?

And they said, $15.

And you said, go ahead.

Not knowing why you needed to replace your PCV valve.

And the reason is because it gets stuck.

It gets clogged with all of these gases that have been moving through it.

Keeping your engine running, keeping your engine.

Well, making it last a lot longer because if there wasn't a PCV valve,

then all of those gases would mix with your oil and destroy your engine.

And a stuck or clogged PCV valve will cause your engine to use oil.

Our bodies have similar systems that get the impurities out, you know, like our kidneys and our liver.

And so that's the analogy that I use for a PCV valve and an oil filter and an air filter.

All these different things that keep our engine healthy and all of it is your responsibility.

It can make a car that would normally last 150,000 miles to last a million miles.

There was this guy that had a, what was it, a Volvo P1800 that he bought new.

I think his name was Art, something or other.

But he lived up in New Jersey or up in the Northeast somewhere and he drove that car for a million miles.

I think he died.

I think the car outlasted him and the car is actually an Volvo museum now.

You know why it lasted?

Original engine, original pistons, all the internal components were original.

The only thing he had to replace was the clutch a bunch of times.

But yeah, the engine lasted.

Why? Because he changed his oil and managed his filters and took care of all the different things before they became a problem.

That's the lesson we all need to learn.

If we want stuff to last, if we don't care, you know, we're going to trade every three or four years before it runs out of warranty anyway,

then it really doesn't matter except to the next person.

But for me, I like taking care of my stuff and you should too.

Well, I hope this little tutorial on engine and oil and PCV valves is just what you needed to hear today.

But if you need to hear something else, call me 423-552-2020 or send me an email to LennyLawson2020 at gmail.com.

And I'll try to help you.

Also, if you want a copy of the My Car Guru guidebook, just send me your email address and I will send it to you.

And it'll tell you everything you need to know about buying, selling, trading, servicing, how to handle body shop repairs.

You know, it's a really good guide on how to avoid spending too much money on things that you just rather not have to spend your money on.

It's better to spend them on vacations and fun stuff.

Well, thanks for listening to this edition of My Car Guru and I'll see you next time.

Why your engine uses, burns or leaks oil AND what to do about it

About this episode

Chrysler LeBaron

engine uses oil

Mazda Rx7

rotary engine

Wankel engine

rotors

Mazda RX-4

Mazda RX-3

exhaust valve

piston rings

oil dipstick

oil disappear in other ways

oil drain plug

oil pump

valve cover gasket

oil smell

Jiffy Lube

over tighten it or under tighten it

manifest itself after you've had your oil changed

car dealership

head gaskets

oil cooler lines

oil coolers

oil pressure

dipstick tube

aftermarket gaskets and seals

PCV

engine oil contamination from crankcase vapors

engine to use oil

air filter

oil filter

clutch

warranty

Request an Explanation

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