My 2001 Series II is going throughan overflow tank of coolant every 500 miles or so. It started about 6 months ago ata tank every few thousand miles and now its every 500 miles. All the gaskets from the lower intake manifold gaskets up have been replaced (for other reasons). There is no sign of leakage in the hoses, water pump or radiator. With this amount of loss, I would expect to see some sign of leakage. Any ideas on what I should check? Thanks. Tom.

 

Go have a coolant pressure test run and you'll find it in ten minutes.

 

Thanks Mike. What's involved in a coolant pressure test? Does it involve pressurizing the system and looking for leak-down? Thank. Tom.

 

That's exactly what it is.

 

I had the same problem on my 99, it was actually coming from that little screw thing on the center of the upper radiator hose... just kinda dribbling out and falling onto the fan, looked totally dry from the top/front but lifting up the house showed the bottom to be soaked.

 

Check your preheat hoses for the throttle body. Clean off the engine and look for OAT sludge on your valve covers on the right side of the engine(if you are in the car). I had a leak in there and noticed it only after I pressure washed the engine. It was the least expensive part I had ever purchased for the Disco. The job was fairly easy for even a mechanical neophyte.

Chris

 

Most shops can pressure tet you coolant system, takes 10 minutes or so to verify a leak and hopefully help you find it.

 

Thanks for the suggestion. I just checked the bleed screw and it's secure.

 

Thanks for the suggestion. I checked these 2 hoses and they look fine. No sludge on the valve covers either.

 

I just borrowed a pressure tester but unfortunately it doesn't have the threaded adapter required for the Discovery expansion tank. I'll try tomorrow to get one with the correct adapter. Cool and simple device though. I plugged it in to my 22 year old BMW M6 which has been slowly losing coolant for years and presto, found the slight leak.