BMW 3-Series E36 (1991 - 1998) - 1997 1.7 rattling BMW?? | Technical matters | Back Room Forum

What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks

Thu 20 Nov 2008 13:52

1997 1.7 rattling BMW?? - telecaster

When I purchased my BMW 1.7 tds there was a rattling/tinny sound from the aux belt tensioner area.

I fitted a new battery and the noise disappeared.....till yesterday that is.

Also on start up the alternator warning light will flicker for a few seconds and then go out.....this does not happen when the car is driving.

I am wondering if the alternator is faulty and is putting the belt and tensioner under stress.....the new battery cured it for a couple of days and after a couple of days (as the battery lost power) the problem reappeared?

I hope this makes sense , or am I barking up the wrong tree.

I am no auto electrician but how do I check for faulty alternator with a small multimeter.

All help appreciated.

Reply | Report as offensive | Link

Thu 20 Nov 2008 13:58

1997 1.7 rattling BMW?? - Screwloose

Far more likely to be a problem with the over-run clutch inside the alternator's drive pulley.

Reply | Report as offensive | Link

Thu 20 Nov 2008 14:41

1997 1.7 rattling BMW?? - telecaster

I should add that spraying the belt with silicone oil stops the noise for a bit.

Reply | Report as offensive | Link

Thu 20 Nov 2008 19:39

1997 1.7 rattling BMW?? - Screwloose

I'm still wondering if it's the pulley; the silicone would slip the belt de-loading it.

Has the alternator drive pulley got a flat plastic front?

Reply | Report as offensive | Link

Thu 20 Nov 2008 22:53

1997 1.7 rattling BMW?? - telecaster

Thanks for the reply Screwloose, no the drive pulley is some kind of metal/alloy.

Reply | Report as offensive | Link

Thu 20 Nov 2008 23:05

1997 1.7 rattling BMW?? - Andrew Moorey (Tune-Up)

might, I say, might be a bit early for freewheeling alternator pulley. Have replaced a few aux belt tensioners where the bearing had spat all its lubricant out and was squealing.
Look for 14.4 (ideal) volts at the battery, more than 0.5v in either direction indicates an alternator problem.

Reply | Report as offensive | Link

Related questions

I rejected a new car - when will I get a refund on the VED?

I’ve rejected a new car and have been refunded my money minus three months road tax. After six weeks, I've had nothing back from the DVLA for the remainder of the tax and the dealer won’t reply to my emails....

What happens to premium rate VED once my car is six years old?

I bought and taxed my car in Jan 2024. It was first registered in May 2019, and had a list price above £40k so for 2024 I paid the additonal tax rate. Since the car will be 6 years old in May 2025 can...

How do I tax a disabled car when purchasing as this must be done by post?

My son has disabled tax status on his car. Soon we will be part exchanging for another car. How do we arrange the new tax to drive home as disabled status can only be done at a post office? Do we just...

Can I appeal the VED premium rate?

I bought a MINI Countryman Hybrid in March 2023. I was very careful to keep the total cost under £40,000. I ordered it in June 2022, but there were a series of delays with manufacture and it was registered...

Ask Honest John

Sell Your Car

Real MPG

Fuel Calculator