Rattle/knock upon starting

[rezmutt]

On my '98 OBW with 116,000 miles: When I started the car up this afternoon, I noticed just the slightest hesitation as it was starting, then a very loud knocking/rattling sound that my wife heard all the way in the house. I turned the thing off immediately. The only thing I could think to do was to check the timing belt, which I did: I removed the passenger-side cover and inspected. Everything seemed fine; the belt was not frayed, and was as tight as ever. I then had my wife start the thing so I could listen for where the sound was coming from. She started it with no problem. There has always been the so-called piston slap upon starting, especially in cold weather, but that goes away. This knocking was louder this time, and didn't go away as quickly. The sound seemed to come from deep inside the center of the block. Nothing at the heads, and nothing up front. We drove the car to town and back (about 50 miles) without incident. What could that strange rattle/knock be?

 

I'd appreciate any feedback.

 

Peace.

[tcspeer]

How long had it sat without being started? When I let mine set three or four days without starting it I also get knocking sound when I start it. I was thinking that it was because the oil was mostly gone from internal engine parts and it was just waiting for oil to get back on parts.

[rezmutt]

We parked it on Sunday, and started it on Thursday. Normally, we park it on Sunday and don't start it until Friday or Saturday, so the time frame is not unusual. I've always heard a knocking, expecially in the very cold, but nothing like this.

 

Could it be something like the a cylinder sleave? Is there such a thing? It still runs, so I guess I shouldn't worry too much, but I expect more out of this car. We bought it at 96,000 miles, and have driven it for 20,000 problem-free miles, and we're hoping for many more.

 

Thanks for the reply

[97subaruGT]

I have the same thing once in a while after not starting the car for more than 3-4 days. It starts rattling like it's falling apart but 10-15 seconds later it quiets down.

 

I wouldn't worry too much about it. It's not Subaru specifc. Our pontiac does the same thing if it sits in one spot for too long.

[rezmutt]

I'll try not to worry about it, as there seems to be little I can do. Seemed fine today. Maybe I'll just have to start it up every couple of days rather than letting it sit all week.

 

 

Peace

[legacy2.5]

what kinda of oil filter are you using? you might want to try a high performance oil filter like a k&n one, which is available at most auto parts stores nowadays. they offer a better anti-drain back valve so there will be more oil readily available at start up and after sitting awhile.

[rezmutt]

Assuming the noise is caused by oil settling, it's probably not the filter. I've used all sorts of filters from the top of the line to the $2 Wal*mart special. I've never had that noise until recently, and only once. Drove the car up in the forest along miles of dirt roads today without any problems. Maybe it's just something I'll have to deal with now and again.

 

Thanks for the input