marlinspike

Mine is plastic...so is the one in the picture, but the one in the picture is getting ready to have catastrophic failure (you know they're ready to break when they turn brown).

The weird thing is, where the pinhole leak is, the plastic is like...melted. the leak is in one of the ribs, but the whole rib area is now level with the rest of the plastic and whitish, almost like you melted it with a lighter and pushed it up from the inside.

As far as the sensor goes - there used to be a different expansion tank. The one pictured is a later style expansion tank, which is all they sell now. There are two differences between early and late: late is more reinforced (the old one didn't have those ribs) and late has the level sensor. On my car, like in the car pictured, the level sensor opening is simply plugged. On later model cars of the same chassis, that has a wire going to it and there is a dash light for low coolant, so you don't have to suffer the indignity of popping your hood to check the level.

I've got a new stock one here, I just don't have any coolant and am in the middle of moving.

marlinspike

Yeah. They start off white. It only takes a few months for them to turn yellow. Eventually they're turn brown which means "replace me." The timing chain rails are the same way.

Fabrik8

If you have a new one, just loosen the hose on the old one, dump everything into the new one, and hook everything back up.

It's probably OK if it's winter though, just watch the temp gauge carefully because that might signal the formation of air pockets from boiling water.

marlinspike

That would make a mess. This car never sees coolant temps over 82C, even if you pound the crap out of it, heck even at 160, unless it's over 80F outside (and even then it never sees 100C), so if boiling is my only worry, I can wait.

Fabrik8

Sorry buddy, I've done everything I can do, the rest is up to you.

marlinspike

Yep yep. I'd go make the mess if you had said my expansion tank is going to burst now that it has been weakened by a pinhole, but based on what has been said I decided it can wait 2 more days.