gbowers

Concerning 1988 RX7 non-turbo, has anyone experienced an infrequent screching noise when reving engine at idle or when shifting during normal driving. Noise sounds like a bad bearing. Please advise.

Thanks,

Gordon

SOLORX7

Sounds like you might have a loose fan/air pump belt,check them first.If there tight,check for a bad water pump/air pump or clutch fan.

gbowers

All belts and water pump are new and work fine. Engine fan runs ok - no noise coming from it or air pump. Where is clutch fan located? Could problem be centered in throw-out bearing.

Thanks.

Gordon

HWO

i have a noise like a shagged bearing in my T2, its an intake leak somewhere on the lower manifold, f@cked if i can find it though

TonyTurboII

I had one of those. Thought it was some kind of bearing, but it was a leak between the lower intake and the block. Come to find out I must have been in a big ******* rush to get the engine together, 5 of the 7 bolts were hand tight, if that.

copandengr

The plain bearings that the e-shaft and rotors turn on are nearly indestructible, assuming you do not run the engine out of oil or overheat it. I have never heard of a bearing failure otherwise and in fact the engines I have torn down always measure out at near factory specs. Plain bearings will not squeal anyway. They will "knock" and then all hell will break loose when they fail. This is not a prolonged process. Plain bearing failure is usually a catastrophic and sudden event.

You are probably hearing something else as the others have suggested. The throwout bearing will sound worse when the the clutch pedal is pushed down, especially if you hold it like that for a while. The pilot bearing is a likely suspect. This bearing is prone to drying out and there is no way to grease it without removing the tranny. Push the clutch in and place the trans in neutral. Rev the engine a little. Now place the trans in a gear and repeat. If the noise is greater with the car in gear then the pilot bearing is a probable cause. The pilot bearing will not squeal at all no matter how bad a shape it is in when the clutch is NOT pushed down. Another way to test the pilot bearing is to get up to a good speed on the road, push the clutch pedal in and hold it and down shift to a lower gear while allowing the engine to idle. This will accelerate the trans input shaft relative to the flywheel and if the pilot bearing is bad the noise will increase.

Belts can squeal even if they are new when the adjustment is not correct. The most likely cause of this is a loose belt. A mismatched belt or a worn pulley can also cause the slippage. A belt that is too tight can lead to premature failure of the accessory it turns by stressing the bearings. For example, a water pump belt too tight will cause the pump to fail very quickly. Ditto the alternator.

Vacuum leaks can sound like a squeal also.

Is the squeal present when the engine is running but the car is not moving? Does it increase in pitch with engine speed? Does it do it worse when the car is in motion? How about when there is a heavy electrical load? How about when you have a load on the engine such as accelerating quickly? These are questions that must be answered to give you a reasonably accurate answer.

The fan clutch is the finned piece of aluminum that the fan blades are bolted to. This clutch is designed to allow the fan to "freewheel" when the engine does not need the fan for cooling. It "tightens up" when the engine temp goes up to make the fan turn at engine speed for more air flow. The clutch is there to save energy by not using horsepower to turn it when it is not needed. To test it you should be able to trun the fan blades quite easily when the engine is cold. the resistance to turning the blades should increase as the temp goes up. This test is done, of course, when the engine isn't running.

gbowers

Thank you for great response and information, much appreciated.

Will make pilot bearing and fan clutch tests as you mentioned and let you know.

Is the squeal present when the engine is running but the car is not moving?

Yes, when engine is warmed up and car is in idle, you can hear a screeching noise when revving engine quickly.

Does it increase in pitch with engine speed?

Yes. Also, noise occurs when down-shifting from third to second gear. However, manual transmission is ok as this 1988 RX7 non-turbo has been maintained meticulously. Recent 13B engine compression test indicated good with no discrepancy between chambers. Recently replaced alternator, water pump, starter, power steering pump and master/slave clutch. Although major clutch rebuild completed approximately 60M miles ago, unsure if pilot bearing was replaced.

Does it do it worse when the car is in motion?

No, same screeching noise if revving engine in idle or while driving car.

How about when there is a heavy electrical load?

No noticeable noise difference with heavy electrical load.

How about when you have a load on the engine such as accelerating quickly?

Yes, noise usually occurs when accelerating quickly or when revving engine quickly at idle.

Thanks again, will update you after testing pilot bearing, fan clutch and all belt tensions.

Liquid Anarchy

iTrader: (2)

Honestly, I have the same problem ( subscribing to the thread + 1 post )

copandengr

The symptoms you describe (primarily the squealing with sudden engine acceleration) are classic for loose belts. Once a belt has slipped very much it may have a "hard" glaze on it that will prevent it from performing as it should even if you tighten it properly. I would probably replace the belts as a next step. Make sure your pulleys are cleaned of any residue that may be baked onto them. Lacquer thinner or denatured alcohol works well for this.

It is very important to get the proper belt tension. Too much will cause slipping, and too tight will ruin your accessories as I mentioned in my previous post.

gbowers

Hi again and thanks for quick follow-up above.

Results of previously recommended tests:

1. Adjusted/tightened alternator belt that was loose or out of spec - more than 1/2" deflection at belt midpoint.

2. After adjusting belt, unable to reproduce screeching sound for clutch pilot bearing test: no noise when revving engine at idle or after downshifting with clutch depressed.

3. Fan clutch tested ok as I could easily move fan with cold engine. Noise not centered in fan area, more in engine area.

I hope alternator belt tightening corrected problem, as I am unable to reproduce screeching sound again after driving car. However, screeching sound occurred infrequently in past - noticed noise when accelerating fast at engine idle and when down-shifting from 3rd to 2nd gear. All engine belts are new - only 2 or 3 months old. I replaced one of power steering pulleys about 1 year ago as it was making a clicking sound.

Will monitor to see if noise re-occurs and let you know.

Thanks again for great help and let me know if I can help you sometime.