Antifreeze pumping out of reservoir
 

We had the head gasket replaced, ran fine for a month, now the antifreeze is pumping out of the reservoir when I'm driving. Doesn't happen at idle or when the engine is reved in park, only when your driving. I ran the overflow tube into a container while I was driving, it pumps out about a gallon in 10-15 minutes of driving. I think the head gasket is blown again the pressure from the pistons is forcing the antifreeze out the reservoir?

Have you checked the cap gasket? The oil will rot the rubber.

Steve

Reservoir cap, water pump, thermostat housing and thermostat are all new, system holds pressure and everything looks normal till you start hauling down the hiway. I noticed a little moisture in the valve cover when I took it off and also in the breather hose from the valve cover to the Air filter, that's why I think the head gasket is gone again.

What car?

On certain models, what's diagnosed to be a head gasket failure can actually be cracks in the cylinder head.

Sixto
91 300SE
87 300SDL
83 300SD

1992, 190e, 2.3 liter. I'm sure the shop that replaced the head gasket didn't check the head, they removed the Head and Intake manifold together, the intake bolts haven't been touched.
jt

Sure sounds like a head gasket to me. What else could produce that kind of pressure in a cooling system?

Which shop did you use? I want to be able to avoid them in the future...

- JimY

Out of curiosity, what coolant do you use?

Why was the head gasket replaced initially?

Sixto
91 300SE
87 300SDL
83 300SD

Many threads ago Benzmac suggested pressurizing the cooling system with the plugs out to see if coolant comes pouring out of one or more cylinders. It won't distinguish a bad head gasket from cracks in the head, but you'll know in which area to focus.

Sixto
91 300SE
87 300SDL
83 300SD

The shop was Allen Foreign & Domestic, the reason for the head gasket replacement stems from the replacement of the radiator, the thermostat housing(they broke replacing the motor mounts), the car still was losing fluid so they determined it was the head gasket, not my car so the work was performed and the only thing that isn't giving a problem are the motor mounts. I'll have to re-do most of the work (the owner of the car doesn't want to take it back, afraid they will screw up more then they fix) I should have just done it all in the first place!
I'm pulling the head tonight, taking it to a machine shop, P & R in Richardson to let them check it for cracks and flatness.

Jerry

Sorry to hear about this nightmare .... I was wondering if when it gets hot is the radiator hot all over as well?

Additionally, this makes me think there is something wrong with the thermostat. Are you sure of it?

Hang in there and keep us posted.

Haasman

the car isn't over heating, all the radiator hoses are firm and I pulled the thermostat and gave it the pot of boiling water test, it opened all the way up. The other thing I did notice was that when I have the radiator cap off and the engine is cold, a vapor starts coming out of the reservoir, I'm not sure, but it has a "gasoline" smell to it. The water in the reservoir is cold, the thermostat hasn't opened yet, so it isn't heat related.
Thanks for all the advice.