I’m a first timer and first wanted to congrats on such a great site….

I have a 1998 S70 and it’s starting to make a high pitch sound lasting only 1 or 2 seconds just after I turned the engine on and it also makes the same high pitch after turning the engine off, but this one last for 3 to 4 seconds. I found a post in your site that suggested the air pump, could this be AC related?

Thanks in advance for your help.

Guanaco1

The air pump usually only turns on first thing in the morning or if the car sits for a long period of time.Open the hood and have someone turn the key on and off and see if the cooling fan goes on and off.If the air pump relay gets water in the relay the pump might stay on with the key.Also just remembered off towards the passeneger side on the dash bye the a/c controls.Look for a hole with some lines.There is a in cabin temp sensor.It is like a little fan it collects alot of dust.Some times they will make the noise you are talking about.I forget exactly where it is.

Thanks Tech... I'll check on that and let you know...

Ok I will be waiting to hear from you.