New guy here with problem...

[RidgeRunner]

Hi guys and gals. I bought a new 98 Legacy GT that now has 43,000 miles and an automatic tranny.

 

Just recently we've noticed a noise that seemingly comes from the drivers side front just after the car first starts moving forward when it's cold only. It goes away within a block or so and doesn't reoccur at the next stop.

 

It's a metallic somewhat grinding sound and my wife did a test this morning on her way to work and emailed me with the results:

 

"I put the car into "neutral" without any gas. The engine slowed with no sound. Then I tried it again driving up towards the stop sign and putting the car into "neutral" with a little gas. The sound became louder in Neutral with gas, the more gas the louder the sound????"

 

This has me stumped. That seems to eliminate brakes or suspension and may center the problem in the engine or possibly the transmission.

 

Anyone have any ideas?

 

Mick

[northguy]

I was going to guess tachometer cable as that is a problem here, but I doubt if it gets cold enough there to be the problem. Don't know enough about newer generation stuff to be much other help. Try Legact 777. He's the man with new gen stuff.

[RidgeRunner]

Thanks Northguy. No it doesn't get as cold here (mostly rain) as it does up north.

 

I thought about the tach cable but I can hear the sound clearly from outside the vehicle as she drives away.

 

Mick

[alias20035]

Originally posted by RidgeRunner

Thanks Northguy. No it doesn't get as cold here (mostly rain) as it does up north.

 

I thought about the tach cable but I can hear the sound clearly from outside the vehicle as she drives away.

 

Mick

 

The tachometer is electronic, so no cable here. The speedometer uses a cable on some models and on occasion in cold weather you will get a buzzing sound from the speedometer unit. But this is an "inside" noise problem.

 

I would guess brakes or a loose exhaust heat shield.

 

By mileage the brakes are at or past due for work.

 

Could it be rust on the rotors causing the noise? The rust on the rotor is scraped off by the first few brake applications and the noise disappears. The scraping sound can even be present even when driving without the brakes applied. The rotors will rust within hours of parking the car if they are wet from rain/snow. This is an extremely common problem, and of absolutely no concern so long as the rotors are thicker than the minimum tolerance, the brake pads are good and the calipers are sliding properly.

 

Sometimes an exhaust heat shield will shift with the first brake application and stop rattling.

 

Also check CV/DOJ axle joints, look for torn/leaking boots.

 

I don't think it is an engine problem, unless the noise changes when the car is parked and you rev the engine. Engine problems should always be present when both parked and driving, and engine problems don't tend to go away (piston slap excepted).

 

Common engine cold weather items are accessorys like alternator, idler pulleys, A/C clutch, timing belt idler pulleys. But like I said, if it does not make noise in the driveway while parked it is very unlikely to be the engine.

 

Piston slap is a clacking sound that generally occurs in cold weather, and goes away when the engine warms up.

 

I have heard that failing timing belt tensioners can produce a sound very similar to piston slap, but I have not heard a failing tensioner myself, just come across the odd leaking one.

 

The transmission is an unlikely source for this type of noise, but check the fluid level, it could be low and there could be air in the transmission cooling system.

 

If you can not isolate the noise to brakes/driveline, I would do the following:

 

remove the A/C belt and see if the noise goes away indicating an A/C compressor or idler pulley problem.

 

Then take the power steering/alternator belt off. This will identify an alternator/power steering pump problem (should be easily identifiable with the belt on too).

 

Then take the timing belt covers out and inspect the belt, its pulleys, the water pump and tensioner.

 

Using this method you should work down to the problem.

 

Also on EGR equipped models, sometimes the EGR will buzz, perhaps it needs cleaning. I had this problem on my 85 GL wagon.

[northguy]

Alias - sorry, didn't mean to disrespect your knowledge level. Your posts have proven you to be another newer gen guru worthy of throwing most any question at. Nice job above.

[RidgeRunner]

Thanks much Alias and Northguy. I appreciate both of your efforts.

 

Yesterday, I put the car on jackstands in the garage and tried to duplicate the sound. No luck. I did check all the heat shields (there's a bunch) and didn't find anything loose. Although while tapping on heat shields I almost think the sound is a harmonic/vibration buzzing sound possibly eminating from one of them, then the sound goes away as they warm up.

 

Since the sound goes away so quickly and I'm not as concerned about a major problem, I think I'll just adopt the old 'wait and see'

approach and see what happens. Next weekend I may do the belt check drill Alias prescribed. Good advice. Thanks again.:santa:

 

Mick

[RidgeRunner]

I'm "resurecting" this old thread with some new info.

 

I've definately traced the offending "buzz" down to the heat shrouds about in the middle of the car. I've been under the car numerous times trying to find the exact problem but to no avail. I've checked all the mounting bolts and banged on everything in sight and nothing seems to be loose or touching anything it shouldn't or damaged from hitting something.

 

The noise has definitely gotten worse and now I can sit in my garage and rev it up in park to about 2200 rpm and it start buzzing like crazy. It happens more often when driving now but still comes and goes.

 

Any ideas what might be a fix for this? The dealer might run into this often but that's a last resort.

 

Thanks in advance for your help.

 

Mick

[Commuter]

Try randomly wrapping hose clamps around various shields. You might get lucky.

 

I've noted that there are some strategically placed screws wedged into the ends of sheilds on my header. It would seem that the dealer of the former owner knew something about quelling these rattles. My 97 OB has not had an issue with heat shields. (Knock wood.)

 

Commuter

[blitz]

Originally posted by Commuter

Try randomly wrapping hose clamps around various shields. You might get lucky.

 

I've noted that there are some strategically placed screws wedged into the ends of sheilds on my header. It would seem that the dealer of the former owner knew something about quelling these rattles. My 97 OB has not had an issue with heat shields. (Knock wood.)

 

Commuter

I successfully used a couple of stainless-steel screws in this fashion to stop a heat shield rattle last week. I drilled pilot holes through the loose end of the shield, then ran the screws through right up to good 'n snug. I think it may have been one of your posts about six months back that gave me the idea. Thanks much.