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Engineers, the Smart Guys

I have a Buick Enclave. I recently changed the oil. I was totally surprised to find the oil filter is smaller than the one on my lawnmower. The other thing I found was that it holds 5.5 quarts of oil. The driver information center gives a percentage of oil life. I am the average driver, city / highway, bumping the speed limit by about 5 mph.

I have two questions. The first question is, considering the size of the oil filter, is it really safe to trust the driver information center to determine when to change the oil?

My second question is, What is it with the smart guy’s that engineer the cars? Why can they not make the oil pan hold 5 quarts or 6 quarts? While I am on that subject, why does the car manufactures not standardize the location of the gas fill? It is an inconvenience for drivers and gas stations. How about you guys leading a campaign for us dummies to get standardization.

Thanks, Ken Fairman

I personally am not an advocate of going more than 5,000 miles between changes no matter what any system or document tells me. My goal is to make the engine last, not to make the oil last. Oil cannot be too fresh.

There’s no real reason to standardize the side that the gas fill door is on. We’ve had a lengthy thread on this subject, and the concensus is that there is no concensus. Cars are designed to be sold all over the world now, and some countrys drive on the left and some on the right, so even that doesn;t work as a justification.

Oh, and I too am dismayed at how tiny the oil filters are getting. Every few years I find I have to buy a new, smaller filter wrench. A few more iterations and I’ll be removing them with a 12mm socket.

The engineers that made the engine are fully confident in the size of the filter, so don’t worry about that. The Oil Life Monitor (OLM) has been vetted by a lot of people, including some very knowledgeable people on this website. Just do a search for OLM to find the discussions.

As far as the oil capacity, a lot of these cars are engineered in countries that use the metric system. The capacities are set for liters, not quarts. 5 liters works out to 5.28 quarts. Variations in the dipstick may make it appear to be .50 quarts low, not 0.28.

It’s not polite in my view to answer a question with a question but I have to ask this: How is it that you don’t trust the oil change frequency and filter size part of your car but trusted the judgment and engineering skills of the designers regarding the rest of the vehicle enough to buy it? Small oil filters have been around for at least 14 years now. The last I looked, the oil change computer provides for a 50% safety factor.

Oil is thinner now so it is less likely that some will bypass the small filter during a cold start. After your oil has been run through the filter several passes, the oil should be clean enough to go unfiltered until the system is disturbed such as during an oil change.

5-1/2 quarts is no big deal. Just use a half quart and save the other half for the next oil change.

Gas cap location? Yes that is problematic and should be standardized with the fill on the left but if you park carefully at the pump, you may find that you can fill on the right with the pump to the left.

At 5000 miles, I pull the dipstick and the oil on it looks almost as clear as the day it was put in. In the old days, oil that was in the engine for only 1000 miles would be pitch black. Modern ULEV cars just don’t contaminate the oil like the old cars with carburettors and chokes did.
So go ahead and change you oil and filter every 1000 miles if you really feel you have to. By the time you drive 300,000 miles you will have done 300 oil changes. Assuming about $45 dollars per oil change, that totals up to about $13,500 spent on oil changes and as a result, instead of lasting 300,000 miles, your engine might last 301,000 miles.

My first two cars didn’t even have oil filters. It wasn’t available on the 1947 Pontiac which I owned first. It was an option on my next car, a 1955 Pontiac, and the one I bought didn’t have that option. I bought the 1955 Pontiac from a Rambler dealer whose service department had overhauled the engine. I continually had problems with sludge getting into the passages to the studs for the rocker arms and causing them to chirp. I installed an oil filter I obtained from the junk yard, but even changing oil and filter regularly, I never got rid of the problem.

As late as 1964, some cars had bypass oil filters instead of full flow. In the bypass filter, only part of the oil was filtered. On your Buick, I don’t think the physical size of the filter is really important. I’m sure it is designed to do the job.

Oil filters became necessary when we went to detergent oils. These oils hold the dirt particles in suspension. The detergent oil was necessary because many manufacturers used hydraulic valve lifters. I prefer a flat head engine where we used a single viscosity non-detergent oil and didn’t have to worry about oil filters, but I guess the good old days will never return.

I have an OLM on my 2003 Olds Silhouette and used it to determine when to change the oil from the start. There are over 100,000 miles on the van and no hint of problems from infrequent oil changes. The state of California did a test in their motor pool of OLMs vs. changes by mileage and found that they OLMs really did work. It saves they a huge amount of money.

One more thing: GM or any other company would not put the OLM in the car if they had questions about it. Their next paycheck depends on their ability to provide reliable, sensible systems that will help you maintain your car properly.

Good point BLE! I teach fleet management and one subject covered in detail is always optimizing the oil and filter change interval.

Our local city busses change oil every 6500 miles; it coincides with other maintenance checks as well. That’s OK for city busses. Highway busses, like Greyhound’s, will go a lot further before the oil needs to be changed.

A normal car owner can optimize as well; Irlandes, one of our posters had analyzed his Mobil 1 in his minivan, and concludes that 8000 miles of driving in Mexico (few cold starts)does not deplete the additives or cause excessive contaminants. His owner’s manual recommends 5000 miles; but that is for the worst case scenario, which the manufacturer has to anticipate.

Agree that 1000 miles is a thing of the past with modern engine design and better oils.

My own formula is to change at least as often as the manual, and make sure the engine will last as long as the rest of the car without needing major work. As a result, the last car I did internal work on was a 1957 Plymouth in the summer of 1964!

considering the size of the oil filter, is it really safe to trust the driver information center to determine when to change the oil?

Yes, It is not the outside size that is important, but if it can filter the bad stuff out. Bigger is not always better.

[i] Why can they not make the oil pan hold 5 quarts or 6 quarts?[/i] 

Remember that same engine is used in other parts of the world.  Do the math and I would not be surprised if that 5.5 quarts may be close to an English even measure.

 [i]  why does the car manufactures not standardize the location of the gas fill?[/i] 

 I can't even guess on that one.  However it just means I need to relearn which side about every 15 years or so when I by a new car.

There are two sides to the gas pump. If half the cars have the filler on the right and half on the left, then the filling station can be used more efficiently. If you have trouble figuring out which side the filler is on in a rental, look at the gas gauge. There is a triangle next to the little gas pump icon that points to the side the filler is on.

There are a lot of factors that go into the oil capacity. Not being an engineer, I would guess that the most important one is to always maintain some reserve in the pan while the engine is running at max RPM, and the rest of the oil is circulating. Also, the amount of oil should be such that the oil never overheats in oil use. Plus factors such as how much clearance there is for the oil pan in the application in which the engine is being used, weight (yes, they consider how many pounds even extra oil weighs for economy), and cost of production.

The gas cap is typically on the side farthest from the hottest parts of the exhaust system, though not always. The best design in my opinion was when it was under the license plate in the back, so you could fill from either side.

The oil filter is correctly sized for the engine application, but I admit I would feel better with more filter material there too. I wouldn’t go more than say, 5,000 miles tops with a conventional oil or 7,000 with a full synthetic despite what the oil life monitor says. (personal opinion) They are pretty good as far as I know, but have no way of telling the quality or grade of oil you’ve put in the engine.

I appreciate your knowledgeable and courteous response.

                                                   Thanks, Ken

My problem is not remembering which side the gas cap is on, it is with traffic flow. My Enclave is on the left. The Merc. I had was on the right. In my experience, most of the caps are on the left so the idea of one lane for lefties and one lane for righties does not work. The problem is when the person that the cap is on the right must go against traffic flow to gas up. Nearly ever time I go to the gas station, there is a line of several cars due to the oil shortages or price jump. It just adds stress to everyone including the station attendant. I have seen fist fights and I am sure that there has been gun play in the past. All I am saying is that one small irritant in life could be avoided if the engineers just picked a side for the fill.

WHAT ! Read the directions. That is a good idea. I had not thought of reading the manual for the recommended oil change interval and comparing the mileage to the OLM. Thanks Docnick.

Thanks Fire; however on some new cars, like new Hondas, I believe, the manual may NOT have a normal recommended mileage or time interval listed. They will tell you to only go by the oil monitor.

On the whole, drivers will more likely do something when the oil monitor tells them than do something when the recommended mileage roll around without any light going on.

Happy motoring!

Thanks for the memories. I remember the old external oil filters and the mess to suck the oil out of the holder. My mechanical knowledge was gained working as a helper to an old mechanic. His solve to the gummed lifters was to add half a quart of transmission fluid to the oil.
Now my car repair knowledge is limited to changing the oil or a fuse.

Search the Internet using keywords such as “GM oil life monitor” and others as you see fit.

I defy anyone to come up with anything that says the GM engine oil life monitor does not work to protect your engine while saving oil.

Check this YouTube video too with people from GM talking about their engine oil life monitor.

I have an '00 Silo with 136K. I bought it at 104K. It spent its life on the oil monitoring system (I have all of the oil change receipts). Going by the view through the oil cap it is the dirtiest looking engine I have ever seen and new oils darkens faster in it than anything else I’ve ever seen. (It is possible that the shop the prev owner used was dishonest and sometimes only reset the message). I ignore the OLM and change every 4-5K.

"GM or any other company would not put the OLM in the car if they had questions about it"
Do we forget about exploding Pintos? GM’s interest is in getting the car past the warranty period. Not in maximizing its longevity.

Yes, lots of people swear the system is ok. I don’t trust it and never will.

Do we forget about exploding Pintos?

The vast majority of Pintos never exploded, I can’t name a single person who had one explode.

Every part in every car is a compromise between affordable and quality, at some point, someone has to say “that’s good enough” or else only millionaires could drive cars. In the case of the Pinto, some lawyer was able to persuade some jury that the Pinto gas tank was not good enough. Its gas tank may or may not actually have been worse than those in other cars.

You may not know someone personally, but the Pinto exploding gas tank is very well documented…

The problem with Ford is that Ford KNEW before the first Pinto was ever sold that there was the potential of the gas tanks exploding if they were rear-ended (internal documents proved that out).