Gas treatments good for your car, if used as directed

Hey there, time traveller!
This article was published 15/10/2004 (7998 days ago), so information in it may no longer be current.

QUESTION — My car is getting to be a few years old and I want to keep it in good running condition. I have been seeing advertisements for different brands of fuel injection gas treatment — the kind you pour into the gas tank. I’d like your experienced opinion on whether these gas additives do as they advertise — ie: prevent buildups on fuel injectors — or whether they can be harmful?

ANSWER — Fuel Injection gas treatment additives generally do work but use them only as directed on the container. The chemicals in the additive are strong and can be harmful to rubber parts in the fuel system if the concentration is too great. Usually, the directions state to add one container of cleaner to a full tank of fuel. Don’t try to clean the injectors quicker by adding more to the fuel tank than recommended or you could be looking at costly repairs in the future.

Most gasoline already contains injector cleaner but in my experience, using an aftermarket injector cleaner does help keep the system clean, especially for vehicles driven for short trips. Injectors form gummy deposits on the tip that changes the spray pattern from a fine mist to a stream. The cleaner can clean up a dirty injector if it is not too bad; however, the chemical isn’t concentrated like the chemicals used at repair shops. If the injectors are dirty to the point of making the engine run rough or misfire or your vehicle has a bad hesitation during acceleration, then you need to have the injectors professionally cleaned.

Repair shops disconnect the fuel lines at the engine and then run the engine on concentrated cleaner with none of it returning to the fuel tank. Running the engine on concentrated cleaner not only helps clean gummy deposits off injector tips but also tends to remove carbon buildup on the back side of the engine’s intake valves that can disrupt the air/fuel flow into the cylinder.

It is possible to remove the injectors and have them cleaned with special ultrasonic equipment, but if the injectors are very bad, even this may not work. Most repair shops will just replace injectors that do not spray properly after they have tried cleaning them on the vehicle.

QUESTION — Recently, I saw a do-it-yourself car fix-it show on TV. They removed a throttle body from a Chevy pickup and cleaned it because the linkage was sticking. They also had to drain some radiator coolant, which I did not understand. They said this whole job would take six hours but I could not understand why it would take that long. They made it look easy. Would a dealership go through this or would they just say you need a new one, remove and replace it?

ANSWER — I am not sure why they did what they did. If the truck has throttle body injection, there is nothing inside for the throttle linkage that needs to be cleaned that can’t be cleaned with the throttle body in place on the truck. The same goes for port- injected trucks, but on port injection there is a coolant hose to the throttle body to heat it and prevent throttle icing. Draining the coolant might be helpful but not necessary.

As for time, television shows edit the material to make it fit the airtime. A task that may take several hours magically appears to have been accomplished in a few minutes. Even so, six hours to clean the throttle body is extremely long. Removing and replacing one takes about 10 minutes. Even with disassembly and cleaning, it should take no more than about an hour. Perhaps they were doing some other work as well that would take more time.

At a dealership, they would first clean the throttle body in place on the vehicle. Occasionally, they need to remove one to clean dirty internal passages but this is rare. The only reason to replace a throttle body is if the throttle plates or shaft are worn so that the throttle doesn’t close properly. This usually only occurs on very high mileage vehicles.

Jim Kerr is an experienced mechanic, instructor of automotive technology and freelance journalist. You can e-mail questions to Jim at the address below.

kerr.jim@sk.sympatico.ca