1992 740 GT SW service light

Falcon · Post by **Falcon** » 10 Jul 2006, 08:24

I recently bought this car without a service manual. The service light keeps coming on and I do not know what is required. It has recently had the timing belt replaced, new distrutor cap, plug wires, belts, and even more recently new heater hoses, so new anitifreeze. There is approximately 172,000 miles on the car.
Also the last time I drove it, while going 70 mph on the Intersate a high pitched whistlle started on the right side. The whistle stopped when at a signal light, started again as I left the light, stopped at the next light where there was an extra long wait and did not commence again. I was on a 55mph road for the rest of the way home.
I am wondering if the whistle and the service light are connected or two seperateitems.
I need a service manual or at leasta list of required services. Your help is appreciated.

Post by **billofdurham** » 10 Jul 2006, 11:38

Sorry I can not help with the service light/schedule as I sold my 740 some years ago. However the whistling noise reminds me of one my 740 had. It took some finding but I eventually traced it to the drain tube from the heater air intake. The tube drains off rain water that collects in the plastic box on the intake. Mine had a rubber flap at the end which was acting like a whistle at speeds in excess of 55mph. I put a small plastic bag over the flap, securing it with a cable tie. To allow the water to drain out I punched two small holes in the bottom of the bag.

It may not cure your whistle but is worth checking out.

Bill.

Falcon · Post by **Falcon** » 10 Jul 2006, 12:02

The day before the whistle both heater hoses were replaced and and also the peice that the hoses attach to. I do not know the name of that part. The mechanic replaced it with a Chevrolet part for $14 and said the Volvo part, which would have had to be ordered, would have cost considerably more.
Many of the parts on this car are original

Post by **billofdurham** » 10 Jul 2006, 12:59

The part I refer to is not an actual heater pipe - it is only a rain water drain. However, if someone has been working on the heater pipes it is possible that he has disturbed the flap in question. That was how my whistle started.

Bill.

wojeepster · Post by **wojeepster** » 12 Jul 2006, 20:10

There is a reset on the back of the speedometer. It is difficult to reach and harder to press in. This will reset the service light. If you are talking about the check engine light then:

http://www.brickboard.com/FAQ/700-900/E ... csinVolvoR