Motor oil

I have a 2002 f150, which calls for 5w 20 but every time I change oil(3000 miles) it is a couple of quarts low. my local garage

suggested 10w30. wondering if it is ok to run this weight in my truck! It is a v8 5.4

I can’t answer your question, but I’m afraid I have to say that it’s not a very good idea to keep running so low on oil. You’re killing your engine. Why don’t you keep it filled up?

I’d Be More Concerned With Letting The Oil Get A Couple Of Quarts Low.

Older vehicles often use oil. Check the oil more often and don’t let it get down beyond one quart without adding enough oil to bring it to “full”.

In warm - hot climates, you could probably go to heavier oil, but I wouldn’t for cold weather. This may or may not help.

Accept the fact that it’s going to use some oil and get on checking and replenishing it or risk blowing it up some day.

Did the garage check your truck’s PCV system?


I would not go to a thicker oil. It is better to burn some oil than it is for the oil to not be able to get to and lubricate everything. I have watched the results of at least one person switching to thicker and thicker oil as his engine burned more and more of it. The engine went downhill very quickly after the change to thicker oil.

Agree with lion; you should check your oil about every second tank full of gas. Top it up as necessary.

How many miles are on the truck? Are you doing any heavy towing with it? Where do you live and what is the typical ambient temperature?

If there are no leaks and the exhaust does not smoke on startup, I would go to a heavier weight of oil. The 5W20 was mainly specified to get the fuel mileage up so Ford would be able to meet the CAFE standards without penalty.

Your oil consumption would fit within the manufacturer’s range, and if the truck was still under warranty, they would do nothing for you.

P.S. Use the 10W30 in summer only; for winter a 5W30 synthetic would be ideal.

"The 5W20 was mainly specified to get the fuel mileage up so Ford would be able to meet the CAFE standards without penalty."
And your proof of this is where?
I can throw out such proof-less statements too.
A big part of the reason for the switch to 5W-20 was to reduce engine wear at startup (when most wear occurs). It was also done to allow the use of smaller oil passages.

77500 miles on truck, it does smoke on startup , live in southeast

It Could Just Be Mainly Valve Stem Seals (Old) And / Or PCV Valve / System.

With only 77,500 miles on it (10,000 miles/year), you’re not talking about going through a lot of oil in a hurry when it’s using 2 quarts per 3000 miles.

Put a quart in at 1500 miles when it’s a quart low and change it at 3000 miles when it’s a quart low, again. That’s only one extra quart every 3000 miles, 3 extra quarts every year. So what?


tardis; the startup viscosity is the first number, in this case 5. The running viscosity is the 20 or 30 once the oil is warmed up. The 20 results in less internal friction, but at the risk of more rapid engine wear. A 20 grade will easily make it to the end of the warranty, but for maximum engine life, a good quality 30 grade is better.

In case you’re interested, a car sold in North America as well as in Europe and in tropical countries will have different oil specified depending whether that country has CAFE standards or not.

I’ve used 20W50 in cars in Asia with no CAFE stadards, while that same car here would need 5W30 Or 5W20. If you don’t believe me, rent a car in Mexico or Brazil and read the owner’s manual.

I bought a new Toyota in 2007, and the manual said 5W30 for all seasons. The dealer now tells me I should use 5W20, because that’s what he is stocking mostly, since the newer Toyota models now use 5W20!! Even Toyota has to meet CAFE standards.

Agree that oils have improved greatly, and engines are now made with narrower tolerances. But if you want long engine life use only 5W20 under “no stress” driving conditions. For optimal engine life, a 5W30 synthetic would be the best choice.

Agree with the valve guide seals; the smoke on startup is a classical leak down situation. Some owners fix those seals, while others just top up the oil.

The cost of the oil probably isn’t a problem.

But I wonder what condition the engine is in if it’s burning that 2 quarts every 3k miles???

I’d like to know if a study was ever done on engine life of vehicles that use a lot of oil when new compared to engines that DON’T use any oil when new. I’ve only had one car which used oil when new (74 Vega)…was rebuilding the engine at 70k miles.

Every other vehicle I bought new never used any oil…and all of them were running fine well past the 230k mile mark…and some well past the 300k mile mark. Personally I don’t think 2quarts every 3k miles is good…

If you live in the southeast, you can ignore Docnick’s advice about switching oil in the winter.

Have you or your mechanic checked for oil leaks? You are losing enough oil that your truck might be both leaking and burning oil.

The way you phrase your question suggests you don’t check your oil between oil changes. That is recklessly careless. Get in the habit of checking your oil on a regular basis, even if your vehicle is brand new.

To answer your question, 10-30 oil will not hurt a thing, especially in your moderate to hot climate…Allowing the oil to go 2 quarts low will cause the remaining oil to degrade rapidly. If you need to add oil between changes, DO IT!!

Mike; there is no real relationship between moderate oil consumption and engine life. We had a 1984 V8 Impala which from 100,000 miles on consumed 1 quart per 2500 miles and ran reliably till we got rid of the car at over 300,000 miles. At that time it still had 100% compression on 6 cylinders and 95% on the other two. I think most of the oil escaped past the valve guide seals.

The original Jaguar straight 6 was designed to use oil, a quart every 1000 miles, and it had a 7 quart sump. These engines lasted a very long time.

Your Vega with a cast aluminum block with no liners (just some plating) was a very flawed, corner-cutting design by GM.

On a modern engine, the main concern with oil consumption should be its affect on the Catalytic converter and the sensors.

Agree that a good engine, properly broken in, and using the right oil should consume virtually no oil between changes. At the same time, you’d be interested to know that my later Impala, which used no oil, was stolen and after 5 days when the police found it, it was down 2 quarts!! The kids that stole it must have driven it wide open!

Right on, Caddyman!!

I’m still not convinced that a engine that uses oil is GOOD…Is it a design flaw…or a manufacturing defect…or is it actually designed to burn a little oil??? If the engine is designed correctly and it’s NOT designed to burn oil…and it IS…then I think there’s a problem and I’d like to see a study of engines that use oil (that aren’t suppose to) compared to the same engine that ISN’T using oil.

or is it actually designed to burn a little oil?

Based on my own experience (four 4-cylinder Hondas and a Chevy L-6) a tight engine will use virtually no oil at lower speeds and loads but use a little (up to 1qt per 2000mi) on long highway cruises, like driving across SE USA at 85MPH.

There has to be some oil present at the top piston ring.
Even though the combustion flame quenches before it reaches the cylinder wall it gets pretty dang hot there on the surface, and the oil evaporates and breaks down.
That oil has to be replenished. Even if it’s only 1qt per 10,000 miles.

That is just the way it is. Using oil is normal for many engine designs.

I would go with 5-30 rather than 10-30. You will get faster flow when cold. Note that the Ford specs probably call for semisynthetic Motorcraft rather than refined dino oil.

Ford switched most, if not all of their auto and light truck engines to 20 from 30 with no changes in the engines. They also issued a retro TSB that said to use it in earlier MY vehicles that had 30 in the manuals. I think it is for at least two reasons, CAFE, and simplicity (cost) in stocking and ordering.

I still run 5w-30 in my '99 Merc. It is HOT where I live. I won’t use it in my wife’s Ford DOHC I4, 2002 that uses oil pressure to push the cam around. The manual says 5w-20 and I don’t know the history of that as well as the SOHC V8.

Remember when owner manuals used to recommend different oils for different temps? No more, that would confuse too many people.

That is just the way it is. Using oil is normal for many engine designs.

But HOW MUCH is the real question…2 quarts every 3k miles is WAY WAY beyond anything I’ve ever experienced…except a badly worn out engine that needed rebuilding…Even my 98 pathy with over 340k miles on it uses far far less then 1 pint of oil every 3k miles.