You could replace the thermostat with a 180 degree one to lower temperature and increase HG life, etc. Big work on cooling system can plug these holes in pix on thermostat with trash, can lead to overheating.

You could also perform a coolant pressure test, parts stores loan or rent pressure testers. Pump up pressure to 15 PSI (cap vents at 18) and leave for an hour, come back and look for leaks. Could be a hose end, etc., here is the plumbing diagram. Lots of places for a coolant leak to happen on a D2.

You may want to spring for $50+ and get your own exhaust-gas-in-coolant tester from parts store, it does maybe 15 tests, you can buy additional chemicals for it. This is a standard diagnostic for HG leaks. You wonder if dealer will be most honest with you on a short term warranty. Don't let them install radiator sealer to fix the problem.

Until resolved IMHO you would be well served to make offspring pop hood and check fluid levels at every cold start.

Do not depend on the heat gauge for diagnostic. It will maintain 50% reading until it is way too warm for most people. Use a scanner or ultra gauge to monitor the temps.

Sneaky coolant loss has put more Discos in the junk yard than you think.

 

replace the MAF or replace the bulb for the check light with a broken one?

 

isn't a pressure test really the only way to resolve this. OP said he had it chemically tested. i hate this leak. crack in expansion tank, bad cap..if you're lucky? no seepage of dark stuff at the back of the engine, no fouled plugs?

 

a preasure test will get you about 90% there it does not easily show internal engine leaks. They will show up leaks eventually if you preasure test over night, but most people dont have that type of patitions.

 

so a small leap of "faith" and a requirement to check/test/swap out everything.

but really a newtome disco at this mileage with loss of coolant and no apparent source would seem to a novice like me like the HG. if he's still using DEX then he would see orange crust at any connection if it was leaking.

as always i'm just reaching but i read a lot and i have two discos with similar problems.

come to think about it, what about that throttle heater. that always leaks. and of course the t-piece and hard lines expansion tank to rad. look at the cooling system diagram and visually inspect the system looking for that orange crap. make sure those hard lines and t piece and screw arent brittle. i lost my HG's there.

that ultragauge or smart phone ap would be superuseful if he was gonna drive thru this fix.

 

Thanks for all the info.....Not really sure if dealer installed new thermostat or not,receipt says he did but it sure don't look new to me....I should have marked the old one it in some way,Maybe the 180 therm will be better.
Also when changing plugs they all looked very good and nothing stood out in any of them to me all looked the sane...no fouling or wet dark crud on them.
Im looking online now for a MAF and found one for 150$ at RoverLand parts but not sure yet what brand it is.
I think Ill look into my own pressure testing kit and chemical block test!!!!!

 

I think someone said Will Tillery has the best prices on OEM MAF. You might give him a call.