98 V70 GLT Transmission Rattling Noise

als98volvo · Post by **als98volvo** » 20 Jan 2015, 11:20

I have a 1998 V70 GLT FWD that has started to make a rattling noise. The noise appears regularly and sounds like a cover is rattling. You can only seem to hear the noise from inside the car. Whenever I get out to try and see where it is coming from, I can not seem to hear it. I believe it is related to the transmission because, when I put the car in gear it stops. The noise comes back when you take your foot off the accelerator. It almost sounds like a metal breather valve that is constantly flapping. I can not sort it out and, was hoping someone could give me some ideas. There has been no change in the transmission. The transmission works as it should. Thanks for the help.

Post by **FLXC90** » 21 Jan 2015, 14:40

Sounds like you may have a loose heat shield?

als98volvo · Post by **als98volvo** » 21 Jan 2015, 16:28

It does sound like a cover of some sort is rattling. I was even thinking a possibility of something with the catalytic converter. The only thing I can't put together is why it stops, when I put the transmission in gear. Maybe quiets a vibration? Where exactly is the heat shield? Thanks for the help, greatly appreciated.

Post by **Ben850** » 22 Jan 2015, 05:49

als98volvo wrote:It does sound like a cover of some sort is rattling. I was even thinking a possibility of something with the catalytic converter. The only thing I can't put together is why it stops, when I put the transmission in gear. Maybe quiets a vibration? Where exactly is the heat shield? Thanks for the help, greatly appreciated.

When you put the car in gear, the engine puts a load to the wheels forcing you to hold the brake as to not move.
That load causes the engine to transfer force across its mounts and torque bushings to hold the engine in place.
It is torque that stabilizes the vibration of a freely idling motor being in gear while holding the brake pedal.

Rattling heat shield, likely in the catalytic converter area, there are several. Look in the rear as well as at the exhaust manifold area of the engine/Turbo.
Just follow the complete exhaust system from the engine to the tail pipe looking for loose exhaust hangers or heat shields.

There is a loose heat shield on the '98 XC I recently purchased. It doesn't make noise, I can see it hanging.
Good luck

Post by **rspi** » 22 Jan 2015, 06:50

What they said. Also check the heat shield on the back of the engine, covering the turbo stuff. You may be able to narrow it down my hanging out of the car while shifting it in and out of gear. Do be careful.

Post by **jimmy57** » 22 Jan 2015, 09:02

Torque converter to flywheel (flex plate) nuts need to be checked to assure they are tight.

Marilyn99 · Post by **Marilyn99** » 24 Jan 2015, 19:08

This is the noise I was getting with my '99 that turned out to be a completely clogged PCV system which had to be replaced. Apparently it's a common symptom. Something to think about.