1.6 '89 Jetta blowing coolant

[BowtieRich]

Hi y'all, this year I got myself a 1.6 Jetta in rough shape. It starts up every time now, but after sitting idling for about 30 minutes it blew a bunch of coolant out of the overflow reservoir.

I started it the next day bone cold, with the overflow cap off, to look for bubbles from a blown head gasket, I see no bubbles but coolant is flowing into it from the small pin hole near the bottom. Pretty certain that's wrong. Do you guys have any advice on where to look first?

[ORCoaster]

I would do the glove test on it when it is cold.  Take off the reservoir cap and stretch a mechanics nitrile or other thin glove, even those food handler ones will work, over the opening.  Now go start the car.  If the glove inflates you can pretty much be assured you have a head gasket to replace. 

That means pulling the head off and measuring the amount of piston above the block and buying another gasket.  Then determine if your head is warped in some way.  You need a good metal straight edge and a set of feeler gauges or take it to a shop and have them check it.  Tolerance is .004 so it does not take much to make things bad for you.

[fatmobile]

The coolant is flowing into the reservoir through a pinhole?
 A pinhole near the bottom of what?

[BowtieRich]

I would do the glove test on it when it is cold.

Good idea, will try. And the pinhole is inside the coolant overflow

[fatmobile]

The pinhole is inside the coolant reservoir?
Leaking to where?