All, My '81 Caprice started making some weird noises last week, and it turns out the air pump seized. My local mechanic claimed the air pump on this car was sort of like a gall bladder - the car didn't need this part. We got into a discussion and he said that all air pump system did was blow some fresh air into the catalytic converter to reduce the percentage of exhaust pollutants so these cars could meet federal pollution standards, measured in PPM...and that in fact, they didn't reduce pollutants at all, only diluted them in fresh air. Sort of like adding water to your scotch. (He told me he has no doubt the the guy who thought of this got a raise from GM.) Anyway, he pulled the rotor on the end of the pump and installed a new fan belt, bypassing the air pump. He says the next time I stop by he'll pull out the rest of the system. Car seems to run fine. I can't notice any difference in the exhaust. This all sound right to you?
Find a mechanic who has a clue. The air pump serves two purposes. When the engine is cold, it blows air into the exhaust ports. This is NOT to dilute the exhaust, it is to allow complete combustion of an unburned fuel that comes out of the cylinder. In the manifold the exhaust is still hot enough to continue burning if more oxygen is provided. Once the engine warms up, air from the pump is switched to the converter. This is done to prevent the catalyst from overheating and melting. Leaving the air pump off will lead to a catalyst replacement in a year or so. Maybe that's what this mechanic is looking forward to.
This sounds perfect alright to me. I had exactly the same thing with mine, most airpump bearings seem to seize after 20-25 years. No noticable difference, I am just not sure about the polution regulations in your state. Here we don't have any restrictions. BTW: Happy new year!!! (We just past midnight here in The Netherlands) Just too late, but you are right Joe. Mine converter was already gone, so no problem there. Converters are only mandatory after 1992 here.
Thinking about what the mechanic said, he is actually right in a way. The fresh air doesn't dullute the exhaust gasses, but burning it outside the cilinders does not really help other then decreasing unburned gasses.
I'm with Joe and Senri on that. Here in Canada, we weren't legislated to have them, so folks would strip the Air Pump and the Catalytic Converters off, back in the late 60s and up to the late 80s models. They wouldn't just take the Airpump off. The whole system. A lot of guys just took the pump off and had fires at the converter.
For what it is worth, I have removed the pump from almost every vehicle I have ever owned that had one. Never had any problem. If it is an issue at inspection time, remove the belt. Reinstall the belt when it comes inspection time, then take it back off. Most air pumps had their own belt that did not run any other accessory.:2_thumbs_up_-_anima
As true of the EGR system the A.I.R. system does not function at idle or WOT. I'm sure if the unit is bad that removing it will not harm anything except in those states (US) where inspection is required. In Ca. they do check to ensure it is pumping air. They do this at idle by checking for airflow out of the bypass valve. If air is felt then the pump is considered good. Burning of "unburned gasses" is a key feature of reducing hydro carbons (HC) measured at the exhaust. The A.I.R. system is good enough that a non-functional pump will result in both a physical fail and exhaust fail in California. In California a replacement pump is less than $30. Engineers may have got a bonus for solving an emissions problem but not because they were making a profit. The first car to feature an A.I.R. system was the 1968 Chevrolet Camaro Z28. Once the auto guys figured out how to manage engines with computers, sensors and internal engine design EGR and A.I.R. systems were deleted.
