I have been having several issues with my 2002 Volvo (replaced air flow sensor, ABS module, emission air box). I continue to have a whistling sound coming out of the engine area. It starts acting upwhen the engine gets hot; then becomes loud and annoying. I used to be able to make it go away occassionally if I reved the engine; now it will not go away. There is also some pinging that can be heard. If in park or neutral and I hold the RPM's up at a constant level,the RPM'sgauge will start goingup and downand you can hear it miss firing. I had one mechanic said he thinks its coming from the manifold area.

Any help or suggestions would be great. Thanks.

 

Next time it makes the noise pull the oil dipstick and see if it stops if it does then the vent box is bad.

 

Is the vent box the same as the crankcase breather? What should I be looking at cost wise?

 

I think the job is around $300.00 if you pay to have it done. Yes as in the crankcase breather.

 

Thanks and that was the problem.
The shop that worked on it are encouraging me to change the timing belt. They said it should be changed after 75,000 miles. Is that a accurate and a necessary repair I must have done? The car has over 109,000 miles on it. Thanks.

 

I would have it done ASAP you are on borrowed time everytime you start it.