Have had my 02' disco from the beginning. Never any problems, other than normal maint. til last week. Have been hearing a sloshing noise from the passengers dash area. On a trip from chicago to nc, temp light went on, temp gauge malfunctioned, pulled car over right away, and popped hood. Coolant was bubbling out everywhere. What could be causing the overheating problem?

 

The sloshing that you are hearing is air in the sytem from the coolant level being to low. If the level is to low the engine will overheat.
How many miles on your truck? When was the last time you had the coolant changed?

 

Youy need to fill the system to the top, bleeding the air out as you go, then go straight to a mechanic and see where you coolant leak is.
If it over heats between now and being fixed, turn the heater on full blast and let the engine idle back to operating temp.

 

87k on the truck. had the coolant changed at the 60k tune up. i spoke with a service tech from RCH and they said the coolant leak might be caused by the throttle body injector, being the gauge malfunctioned and will not respond.

 

Leaking from the throttle body heater is a very common and easy fix. Have it looked at right away. Make sure that the coolant level is full before you drive it.
If the temp gauge doesnt work then I would have it towed.

 

Am going to change the throttle bodyheater tom. also the nipple at the reservoir to the throttle body heater hosehas broken off. Hope any more damage was not done, being the SES light came on after I filled the coolant and started the vehicle.

 

They may or may no be related. I would fix the leak and then go from there.
Is it the Service Engine Soon or Check Engine light that came on?

 

It is the service engine soon. The oil is not milky, and I am going to pull the plugs to check for coolant. Any other suggestions on the problem are much appreciated.

 

The service engine soon light is a emissions reminder, it wont show any codes with a normal scanner.
If you go to www.discoweb.org and click the "tech" tab and then scroll down there is a link on how to reset the SES light.
It works for a DI not sure if it will work for a DII but it is worth a look.

 

Only for a D1..