Recently, I replaced thermostat on my Disco 1 because the reservoir was boiling over. After replacing, it has overheated a few more times and now it seams to be ok. I'm not fully sure the problem is fixed. I checked hoses, and Radiator for leaks, all is well. Could the problem possibly be the water pump?
How much radiator fluid should be in the reservoir? Presently, I don't see fluid in the reservoir now.

 

Mine is full?

 

Do not drive if you are not sure.The reservoir should be about half full.Are you sure you
installed the thermostat the right way(spring in the block,steam hole at 12:00)and did you make sure you got the air out?

 

What he said; sounds like there's still some air in the system.

 

There is a "X" in the bottom of the res, it needs to just be covered with coolant.

 

My stat didnt have any marks on it. How safe is it to run without the thermostat in it.
I know its a dumb question, but i gotta ask it.

 

The only stupid question is the one not asked...depending on where you live you could drive it forever with no t-stat in it.
All the t-stat does is regulate engine temp and help warm the engine up faster.
A cold engine needs more fuel than a hot one.

 

As stated the coolant should come to the top of the "x" tower, yea most likely air in system still, and do you have a white or black reservoir? The black is original equip and those tend to get leaks that start small and cause problems too. I would imagine without the stat you won't get the coolant as "cooled" in the radiator in the long run. But then again that's an ongoing argument around here and other places to stat delete or not. Usually see folks do it to try and hide another offending cooling problem, with the increased coolant flow. But others would say different. As spike said, your location is a factor as well to whether its a benefit or risk.

 

Ron6977 -

I tested my D1 in hot weather (90's) with no stat (ran 145-150), 160 stat, 180 stat, and 195 stat. I'm 120 miles north of the Gator state line, but it gets to 100+ here in summer. IMHO no stat and 160 are too cool for the oil to get to best operating temperature, so engine wear may slightly increase. The ECU may try to run a richer mixture. I stayed with the 180F stat.

From what I have seen at the boneyard, vehicles with no stat are a sign previous owner had overheating problems and could not fix them.

You can also get a great deal of improvement by having the D1 radiator (copper & brass) rodded out for calcium, a small indy shop near me unsoldered the side tank, rodded out, and hot flushed with citric acid for $75. Your radiator should be about 10F or less top to bottom in the same vertical line on the fins, the rows run horizontal and bottom ones gunk up first. Eventually with only a partial radiator the lower tubes are a lot cooler (low or no flow) and the engine is hotter that it should be.

 

Im not overheating by the stock gauge in the truck. (Dont have a digital one yet) But i am loosing fluid. Im also the one that has the head gasket problem but Some repair additives ive put in have seemed to help a lot. No more white smoke, Im sure its not sealed 100%. I dont know if this is common for Disco or not but there seems to be a lot off pressure on the system, My rez. is a tan color and when its hot the tank looks like a balloon and the top rad hose also expands a great deal. Ive put up to a gall. of fluid back in the rad. a day.
And i do raise the left side of the car and burp the rad.

Also Sorry Rovermancz8 for jumping in your post with my own problems.