My s13 has an exhaust leak, so I parked it and drove my truck to work this week. Car used to drive perfect, but after sitting for a week it seems the headgasket is blown, and there is no compression. I am not 100% sure until I check in a couple minutes...

 

#4 cylinder compression: 30psi

Not the rings, possibly the valves, but yeah right.

Anyone have any explenation as to why it would wait until its been sitting for a week or so to happen?

 

how did you check compression? Did you hold the throttle down tot he floor when cranking? maybe you bent a valve somehow on the startup.

 

I had a problem a few years ago with what I though was a stuck piston ring, and I was loosing compression, I belive the trick to fix it was take a cap full of auto tranny fluid and pour it in through the spark plug, and let it sit over night and that was supposed to usually "unstuck" it. Mine turned out to be that I was missing half a connecting rod. (Never buy motors from shady people) leson learned.

Somebody else chime in on the stuck ring solution, Never hurts to try it, and see.

 

Does it still run? i blew my head gasket once and had about 20 psi of compression in the front cylinder, but it wouldnt heat up, i drove it on three cyl. for about a week untill the head gasket came in. it blew in-between cylinders and it would leak compression from #1 into 2. so it might be blown. but i have no idea why it would just let go after just sitting..