Carbon Deposits Can Interrupt Supply of Fuel

Question: I have a 1988 Toyota Camry with 24,000 miles on it that has run perfectly until now. I have to keep cranking the engine in the morning before it starts. Then it sounds like it is flooding. After the first start-up, I don’t have any problems for the rest of the day. I have tried using fuel injector cleaner, but that hasn’t helped. What is causing this problem?

--J. D.

Answer: The problem is probably not caused by a dirty fuel injector but by carbon deposits on your intake valves. All car engines develop deposits inside the combustion chamber, and late-model cars are very sensitive to the problem.

The deposits disrupt the flow of fuel across the intake valve and cause an overly lean burn, meaning that an inadequate supply of fuel is being burned. Once the carbon deposits warm up, the disruption of the fuel supply is less pronounced.

A number of companies make gasoline additives intended to remove engine deposits. You might try one of these products, although extremely hard engine deposits can be removed by only physically cleaning them after the engine has been disassembled.

It is possible that a dirty fuel injector is causing the problem also. Dirty injectors sometimes act erratically, so that the engine would run poorly only when cold. A garage should be able to use a more powerful cleaning fluid than is available on the retail market or replace the injector if it is shot.

Q: I have a 1970 Dodge Dart with a slant-six engine. For the past 11 years, I have used Arco Graphite 10-40 oil. But it is increasingly difficult to find this oil in stores. Can I safely switch to something else?

--C. V.

A: The Dodge slant six was one of the greatest engines ever made, and yours should do just fine without Arco Graphite. The company did not have much success with the oil, in part because of the black color.

The graphite was added as a friction modifier intended to help reduce engine wear. In that sense, it did offer some of the same benefits as Teflon-type oil additives that are being widely advertised today.

But newer oils offer greatly enhanced lubricating qualities. You should look for an oil that is rated as Energy Conserving Classification II, which often has friction modifiers added. These oils, available since 1988, provide a 2.7% improvement in fuel economy over straight oil. By comparison, Classification I oils provide just a 1.5% improvement in fuel economy.

Q: I would like some information on maintaining the wheel bearings on my 1986 Toyota Corolla. Is it possible to lubricate the rear wheel bearings, and how do I know when either the front or rear bearings need to be replaced?

--R. S.

A: The rear bearings are a sealed unit and cannot be lubricated. All you have to do is just keep driving until they start whining and then replace them. Until 1984, it was possible to lubricate the front bearings on a Toyota, but since then they also are sealed units.

They are angled ball bearings that automatically are loaded with the proper amount of tension, so they should not wear out unless they were defective or lose their lubrication.

The replacement is relatively easy, although the bearings can be costly. You are unlikely to get out of it for less than $100. The mechanic will almost certainly want to replace both the left and right bearings when one of them fails.

I say ignore that advice, which is obviously self-serving for the garage. Just fix what is broken. The other side could last another 25,000 miles.