strange noise

[mr and mrs noodles]

my wife has a 99 beetle. she's had it for a few years and had very few problems with it thus far. however, lately its been making a weird noise on cold starts. its like a low pitch grinding or rattling noise. of course when we have it at the shop it doesnt make the noise. we had the timing belt and water pump replaced today and the mechanic checked it over pretty well, but couldnt find anything.

he had mentioned earlier it might be the starter or the secondary air pump, which seem to be common problems from what i can tell by browsing the forums. but after doing some searching im not sure if thats what this is. those seems to be high pitched or a "kazoo" sound. this doesnt really sound like that.

like i said, its usually only on cold starts and it doesnt last more than a minute or two. any ideas?

[BUGSTUFF]

For 90 seconds after a cold start??? I'd say the secondary air pump.

Wait for it to get unbearably loud or quit altogether and then replace it with a used one. Or, if the rivets are pulling out and separating the case halves, you might be able to fix it and quiet it down (pull out the rivets and replace them with screws).

[mr and mrs noodles]

it almost sounds like something is rubbing on something else. i started it tonight to see if i could hear it. i wasnt really doing it till i put it in reverse and backed up a little, does it in other gears too. my wife said its lasting longer today. im off on friday, so im gonna try and see if i can find anything loose or rubbing. its kinda driving me crazy not being able to figure it out

[VdubOne]

Originally Posted by mr and mrs noodles

my wife has a 99 beetle. she's had it for a few years and had very few problems with it thus far. however, lately its been making a weird noise on cold starts. its like a low pitch grinding or rattling noise. of course when we have it at the shop it doesnt make the noise. we had the timing belt and water pump replaced today and the mechanic checked it over pretty well, but couldnt find anything.

he had mentioned earlier it might be the starter or the secondary air pump, which seem to be common problems from what i can tell by browsing the forums. but after doing some searching im not sure if thats what this is. those seems to be high pitched or a "kazoo" sound. this doesnt really sound like that.

like i said, its usually only on cold starts and it doesnt last more than a minute or two. any ideas?

I had this problem, check under the car for loose exhaust components, when my car would warm up the sound would disappear, i replaced two hangers because the central pipe was resting against the center crossbar when cold

[Nicefeet]

It might be worth investigating the oil pump chain tensioner. They’ve been known to shatter on early AEG motors.

[Smileybug]

Originally Posted by Nicefeet

It might be worth investigating the oil pump chain tensioner. They’ve been known to shatter on early AEG motors.

Can you elaborate more on that? Never heard of anything like that happening. Didnt know there were any chains in the 2.0s.

[simonsi]

Originally Posted by Nicefeet

It might be worth investigating the oil pump chain tensioner. They’ve been known to shatter on early AEG motors.

Could be, but as it runs in oil all the time I'm not sure why that would only show on cold starts

[simonsi]

Originally Posted by Smileybug

Can you elaborate more on that? Never heard of anything like that happening. Didnt know there were any chains in the 2.0s.

The 2.0 has a chain in the sump that drives the oil pump and balance shaft. As it runs in oil it isn't a serviced item, it should last the life of the engine.

[Nicefeet]

Originally Posted by simonsi

Could be, but as it runs in oil all the time I'm not sure why that would only show on cold starts

The chain tensioner is not bathing in oil; it’s above the level of the oil pan. It could "in theory" be loud until oil is splashed on what’s left of it it. It’s made of plastic and gets brittle, cracks and falls into the pan.

Only down side that if it is the tensioner, the timing belt and lower timing gear has to come off to replace it. I did not even know mine had shattered until I dropped the oil pan to reseal it. I wish I took a picture because I nearly had a heart attack when I found it.

It has been reputed on the TDI forum that it is very rare that they do crack, but it has been known to happen on early AEG motors from what I have read.

[simonsi]

Originally Posted by Nicefeet

The chain tensioner is not bathing in oil; it’s above the level of the oil pan.

No, I was referring to the chain which IIRC correctly has its lower half below the oil level so the whole chain should be lubed with a 1/2 turn of the crank which is why I would be surprised it made a noise only on cold starts, doesn't mean it won't, I find all sorts of stuff on these cars surprising

[Beetle1.8turbo]

Originally Posted by BUGSTUFF

For 90 seconds after a cold start??? I'd say the secondary air pump.

Wait for it to get unbearably loud or quit altogether and then replace it with a used one. Or, if the rivets are pulling out and separating the case halves, you might be able to fix it and quiet it down (pull out the rivets and replace them with screws).

i see one rivets is half way out it make's a noise for 5 sec on cold start and the engine light come's on sometime when i hear that noise. any idea if i need to replace the pump ?

[Smileybug]

Have you had the car scanned for codes?

What kind of noise is it making? More like a grinding noise? If its only for a few seconds on cold starts, I'd say its more likely the starter. Mine does the same thing. Won't cause any problems, just a dirty starter.

[Beetle1.8turbo]

one rivets is half way out it on the secondary pump what should i do use a bolt amd a nut???. . .

[Palmettoguy]

Originally Posted by Beetle1.8turbo

one rivets is half way out it on the secondary pump what should i do use a bolt amd a nut???. . .

http://newbeetle.org/forums/technica...tion-pump.html

[Beetle1.8turbo]

Originally Posted by Palmettoguy

http://newbeetle.org/forums/technica...tion-pump.html

Thank you