Losing Coolant from Resevoir overflow

[MiaRover]

My 2001 Discovery II keeps ejecting coolant out of my overflow resevoir thru the overflow discharge hose. There seems to be a great deal of pressure
built up and there is a hissing noise from the top of the coolant resevoir around the spout that the cap is screwed into. I purchased a new resevoir cap but that was no help and there is still the hissing. The overflow hose will discharge coolant at a rate that will deplete my coolant within a normal daily commute, which is about 20 miles.

Has anyone experienced similar problems and what can I do about it.

[Disco Mike]

One of two things, bad t/stat or head gaskets blowing exhaust into the coolant system.
Either way, you need to quit driving it till you can get it into a shop.
Don't put this off or you will toast your engine.
Mike

[Alak]

I would suspect a head gasket. The coolant will still circulate through the engine via the heater hoses, and various bypasses, even with the t-stat closed, just not nearly as efficently.

[RudemanRB]

I think T-stat, usually that's the 1st thing that goes.
if it was a head gasket wouldn't the engine idle a little rough?

[MiaRover]

Thanks for the suggestions! The problem is that the head gasket had been replaced as well as the thermostat and radiator. I had also noticed when eccelerating there is bubbling noise coming from the heater vents. The engine runs well and does not overheat.

[Alak]

Could be a plugged radiator, or big air in the system.

Your right RudemanRB. It would be likely to have a rough idle if it did leak.

MiaRover: Does it miss when you accellerate hard, or accellerate in general?

[MiaRover]

No miss, as I said it runs smooth! Plugged radiator? Air in the system? That thing was flushed twice before radiator was installed.

[Disco Mike]

You need to go back to the basics before you toast your engine, I don't care what has been done in the past, you have a problem.
So go for a pressure test first.
Mike

[Alak]

Originally Posted by Disco Mike

You need to go back to the basics before you toast your engine, I don't care what has been done in the past, you have a problem.
So go for a pressure test first.
Mike

I agree.

I remember one time they replaced an engine in one of my mazda's. It ran like poop until time to change the airfilter. They left a couple shop rags under the bonnet and they made their way into the airbox. Ran real good after that.

[wimp]

I agree with Disco Mike. get back to basics.
It is VERY possible that the head gaskets were not the original problem and you actually had a warped head. A new head gasket would have apparently soveld the problem temporarily until the pressure wore out the gasket material prematurely. In any case, there can be many scenarios. A pressure test can help narrow down the source of your problem. Once you get the results, get back to the forum and let us know.

[teepee1]

Hi, did you ever find what the bubbling noise was. My disco has just staarted making a bubbling noise comming from the center dash area.
cheers

[DailyDrivenTJ]

Originally Posted by teepee1

Hi, did you ever find what the bubbling noise was. My disco has just staarted making a bubbling noise comming from the center dash area.
cheers

You have air trapped in your cooling system.

Watch your coolant temp as you drive and keep your eyes on the coolant bottle and keep it full. The bubbles usually make their way out by themselves.

[Disco Mike]

You have checked a lot and missed something. Go back to the basics, coolant pressure test and chemical block test. Just cause you have replaced alot of items including the head gaskets, doesn't mean they were done right and have not failed.
Mike