Clatter on startup

[marx404]

The past two Sunday mornings (after sitting overnight) when I start my Astra I hear a very brief clatter under the hood for a millisecond, like a diesel clatter or something. Then the engine quiets down. No problems running and I always let the car idle for a little bit before driving it. What could it be?

[mamapan]

Originally Posted by marx404

The past two Sunday mornings (after sitting overnight) when I start my Astra I hear a very brief clatter under the hood for a millisecond, like a diesel clatter or something. Then the engine quiets down. No problems running and I always let the car idle for a little bit before driving it. What could it be?

Ditto! It doesn't happen every day to me but once in a while I get the same thing! We have 2 2008 Astra XE's in the household. I'll have to drive DH's to see if his does the same thing...

[marx404]

I had my car in the shop today to have my alternator and accessory belt replaced so while it was in, I had my tech check it out and he was puzzled. He checked for any TSB's on the noise but there were none. The shop manager suggested that this sound is common in mechanical lifters sometimes. (true?) My tech said he will try to find out more about it.

[Astra La Vista!]

Originally Posted by marx404

The shop manager suggested that this sound is common in mechanical lifters sometimes. (true?) My tech said he will try to find out more about it.

He would be right if he was talking about hydraulic lifters, but our cars use solid mechanical lifters. Hydraulic ones have a LOT more clearance than solids until oil pressure builds and fills the chamber inside.

However, there are other hydraulic components in our engines that require oil pressure to prime. I'm not sure if your timing belt tensioners are hydraulic or not, but the VVT oil control valves are electronically operated.

[paulff3]

I too am apart of this. Happens more frequently in colder temps. I thought it was the exhaust shaking on initial start.

[72gssaturn]

i too would say the clatter is from the solid lifters, at startup.
solid lifters are never as quiet as hydraulic lifters, at any time.

[Astra3Dr]

The longer mine sat or the colder it got the more I would hear the clatter, sounded like lifters to me

[Astra La Vista!]

Originally Posted by 72gssaturn

i too would say the clatter is from the solid lifters, at startup.
solid lifters are never as quiet as hydraulic lifters, at any time.

Originally Posted by Astra3Dr

The longer mine sat or the colder it got the more I would hear the clatter, sounded like lifters to me

Ah, but he said that he only hears it for a split second, and then quietens right out. If it was noisy solid lifters, you'd likely hear it all of the time no matter what temperature the engine was at.

[marx404]

Originally Posted by 72gssaturn

i too would say the clatter is from the solid lifters, at startup.
solid lifters are never as quiet as hydraulic lifters, at any time.

so I wonder why only once in a blue moon it happens?

[d MunnY No1]

My car makes a funny noise too. I thought it was a clatter noise because it kinda sounds like loose metal somewhere. It never happens in cold weather but in hot weather it happens when i start the car and when I hit the gas or my car shifts. But it is only for a quick second. I thought it was my exhaust until I had a friend sit on the hood of my car with the hood open and accelerate. He immediately said it was a belt. So our conclusion was that the hot weather slightly stretched the belt out. After about 5 minutes of driving it goes away after the engine gets the air flow. The more I listen to it i can tell its a belt. If I slowly press the gas I can make the noise drag out for about 4-8 seconds until i hit about 15 MPH as far as cold weather I have had my car in temperatures ranging from 10 degrees to 110 degrees. And I have only experienced this weird noise on a daily basis on start up in hot weather around 70-110 degrees as it reads on my info center.

[Spaztrick]

I too have this same clatter. I experience it on a daily basis. The only time I won't hear it is if I have the air conditioning off at the time of start up.

[polizzi82]

Originally Posted by Spaztrick

I too have this same clatter. I experience it on a daily basis. The only time I won't hear it is if I have the air conditioning off at the time of start up.

BTW I've been noticing this ever since this thread, thanks

It's like "YOU ARE NOW MANUALLY BREATHING"

[96r50]

Originally Posted by Spaztrick

I too have this same clatter. I experience it on a daily basis. The only time I won't hear it is if I have the air conditioning off at the time of start up.

X3 on this!

[marx404]

Ok, I have found that if I turn the ignition key to run position and let the "jet whining" sound subside (I assume that is some sort of fuel or oil pump???) before starting the car, I no longer have the clattering noise.
Try it and see for yourself.

[dmoser]

Might be the fuel injectors.

[Gary F.]

Originally Posted by Spaztrick

I too have this same clatter. I experience it on a daily basis. The only time I won't hear it is if I have the air conditioning off at the time of start up.

I have same issue, apparently a slight belt slippage at startup and during the first few accelerations when you drive, then it goes away. Only does it, or does it more, with air conditioning on. Turning the key to "on" until the whirring sound stops does not seem to change anything about the belt slipping. This began at about 10K miles, which has coincided with warm or hot weather.
Has anyone tried tightening the belt?

New here, my first post. What do we do for service manual? I see Haynes UK site lists an Open/Vauxhall Astra manual. Thanks all!

[dmumbles]

Check the thread about the alternator pully. Mine started off like everyone elses. it first started in the cold then in summertime. Trust me it get s worse.
My does a rattling/ hissing sound now everytime I start it. It eventually after quite awhile goes away. It sounds unhealthy for the car. Push for it to get fixed. I am still having problems cuz the dealership does not want to acknowledge that there is anything wrong. Try taking it to a mechanic shop that does warranty work. See what they say!

[wandern]

I've always suspected that the startup clatter is related to the cam advance. Since we have solid lifters (instead of hydraulic), you don't have to wait for them to become pressurized, so if it was solely the lifters, you'd hear it all of the time.

On the other hand, the camshafts do have variable timing and they don't move instantaneously. I suspect that the momentary clatter may happen until the cams have moved to their appropriate location for the given engine RPMs and ignition timing.