I have a 95 disco 3.9 that seems to blow out coolant when I park. The temp gauge never shows it is hot. It has a new thermostat as well. The coolant res. seems to have a sealed lid, where is the pressure relief in the system. I can never tell where it comes from. Any ideas??

 

General area? There's no way we're gonna know where it's coming from. You'll just need to have a closer look and get back to us.

 

There is no such thing as a "sealed" cooling system.
Ontop of the black overflow tank on the passenger fender is a cap, remove it when the engine is cold, should be half full.

 

You need to figure out where the coolant is coming from. Your choices (generally) are:

1) Front and rear, seam between the cylinder heads and the block
2) Water pump
3) Front engine cover
4) front rear valley pan gasket
5) Throttle body heater plate
6) Cracks in any of those crappy hard plastic hoses
7) Those crappy factory hose clamps

You gotta get your hands dirty though. A clean engine helps as does dye.

 

Where is the pressure relief for discos?

 

I believe the cap of the overflow tank keeps the system at a certain pressure. There is a coolant overflow at the top of the tank. Don't ignore a coolant leak in these trucks. Go to a Napa and buy a little bottle of coolant dye if you need help finding the leak or better yet get your coolant system pressure tested.

 

have you bled the cooling system?

Get a new reservoir cap, bleed the system and see if anything changes.

 

Whats the best way to bleed the coolant system? I read the method in another thread on D2's, the D1 doesnt have the same hardware.

Thanks

 

Bleeding a DI is the same as a DII, only the parts are in a different location.
Remove the fill screw ontop of the radiator, fill the overflow tank until coolant come sout of that hole.
Replace fill plug on radiator.
Start truck, with heater on HOT and cap off of overflow tank.
Same as a DII.

 

Thanks for the help!!!