Pressure in coolant tank?

[Tmarkle]

When I pop the cap off after driving in my 1.6 d there is a hiss, but no oil in the coolant or vise-versa. The gasket leaks at the center of the drivers side of the head right under the water fitting also. What will it cost USD for me to replace the gasket? I know the parts aren't bad price but what will the cost be to have the head decked? There is no white smoke (except on cold start) and like I said no fluid mixing. Has anyone had good luck with any pour in sealants? I know normally they don't work but I've read good things about blue devil. How difficult of a job is this?

[Fatmobile]

Common for there to be pressure in the resevoir when the coolant is hot.

If it's leaking between the head and block right under the coolant flange that heads to the radiator,..
that's usually oil. Oil pressure passes from the block to head there.

I don't like to deck a warped head on an engine with an overhead cam because it makes the cam rock like a teeter tooter.
If it is just leaking from the flange gasket there is no need to pull the head,.. just change the gasket or o-ring.

[Tmarkle]

Common for there to be pressure in the resevoir when the coolant is hot.

If it's leaking between the head and block right under the coolant flange that heads to the radiator,..
that's usually oil. Oil pressure passes from the block to head there.

I don't like to deck a warped head on an engine with an overhead cam because it makes the cam rock like a teeter tooter.
If it is just leaking from the flange gasket there is no need to pull the head,.. just change the gasket or o-ring.

I gave it a taste test and it is definitely coolant, so it must be that o-ring.

[Fatmobile]

Yeah, even more likely if it's the one with the o-ring than an old rabbit with a gasket.
I spread some silicone grease on the surface to help seal out moisture and keep the aluminum from corroding.
I think petroleum grease can mess with the material in the o-ring.

[Tmarkle]

Yeah, even more likely if it's the one with the o-ring than an old rabbit with a gasket.
I spread some silicone grease on the surface to help seal out moisture and keep the aluminum from corroding.
I think petroleum grease can mess with the material in the o-ring.

It's an '85 Jetta so I imagine it's the o-ring version.

[greg lousy]

also worth checking the stream from the little breather hose going from radiator to reservoir. There are videos on you tube showing what the pour in sealant does. Eric the car guy has a good one. Sounds like you're not doing it as you didn't mention it again. In my opinion, using that stuff for problems as minor as yours would be nuts. Even with major problems, Its kind of a desperate move.

[Tmarkle]

also worth checking the stream from the little breather hose going from radiator to reservoir. There are videos on you tube showing what the pour in sealant does. Eric the car guy has a good one. Sounds like you're not doing it as you didn't mention it again. In my opinion, using that stuff for problems as minor as yours would be nuts. Even with major problems, Its kind of a desperate move.

I've discovered it's just that little o-ring and it's quite a while before my low coolant light comes on so I'm not too concerned, just gunna replace the o-ring.

[Tmarkle]

Well... I have confirmed that the head gasket it probably shot. I replaced the water outlet and the o ring. On my test drive after about 5 minutes the water temp for high enough to blink the light at me. I immediately shut it down. The coolant tank had a ton of pressure and it was leaking from the same spot on the head gasket as before. After it cooled down I drove it home and the temp was on the rise quickly by the time I parked it. Hopefully the head isn't severely warped. A local shop quoted $75 to deck the head and $150 for a full valve job. Seem reasonable? Should I do a metal head gasket? Can the head be removed with manifolds and the turbo still attached and without removing the IP?

[Fatmobile]

Go back and take a look at what greg said.
Since it's not the o-ring it could be a plugged resevoir coolant line.

[Tmarkle]

Definitely was the head gasket... won't let me upload a pic of the gasket but she was shot.