Hey everyone,

I have a 1996 Discovery with 108k miles. With this recent extremely hot weather in the south, my disco has been running a little hot in traffic although it does not happen all the time, even on equally as hot days. I have done all the basic checks: coolant level, coolant appears clean, no leaks, water pump looks fine, viscous fan is working properly, and expansion tank cap. Another oddity is I have a new AC condenser less than a year old blowing cold air. However when the truck begins to run a bit hot and go over the halfway point on the gauge. The AC starts blowing condensed water vapor (fog) out of the vents and this only happens when the temperature begins to climb. The auxiliary fans kick on and suck air through the grill as they should. I am wondering if the engine just cant handle the AC and the ambient temperature of around 95 F this time of year. It did not do this even when the temperature was around 90 F. I am also wondering what a 3/4 high temperature gauge roughly translates to? Do you think i should stop driving until i have time to fix myself or bring to a mechanic? I have not driven far when it runs hot as i only use my disco for running around town, luckily not my daily driver. I appreciate any insight you may have for someone new to this forum.

 

The electric fans in front of the A/C condenser (just behind the front grill) should run whenever the A/C is on.

They should also turn on if the coolant temp rises above 220 if the A/C is not on.

 

As far as a translation on the 3/4 temp gauge, anything over 1/2 is worrying, in fact many people (myself included) are neurotic enough to worry about their coolant temps before the gauge has even reached the halfway mark. The standard dash gauge on these cars is a pretty coarse measurement, and personally I'd define a needle pointing to 3/4 to be an overheat condition. Standard operating temperatures vary pretty widely within a 35-40 degree window (185-220), a way smaller difference than you can measure with the dash gauge. Most people on here, or at least those of us who have dealt with cooling issues, have a special aftermarket instrument called an Ultragauge, which plugs into the OBD port and allows you to measure the coolant temperature much more closely than the thumb-in-the-air-and-squint precision of the dash gauge. It's about $80 and it's a fantastic investment. That being said, chances are it's not going to contradict an overheat indication by the dash gauge unless one of your coolant temp sensors is faulty (dash gauge and OBD measure coolant temp via two different sensors right next to each other near the thermostat housing). It would enable you to detect and monitor a mild overheat condition that isn't detected by the dash gauge. Might want to save your $$$ as many overheating issues on these cars are thanks to a head gasket problem...

Might want to stop driving and get it looked at...

 

welcome to my world,97 d1 with 110m,runs great but temps do creep up over 200degrees,all my equipment isn't that old but i would start with the basics,how long has coolant been in there? maybe change,try a 180degree t-stat,add a bottle of water wetter and yes an app with a wifi dongle does help moniter temps,only time my dash gauge went to 3/4 was due to a viscous fan failing

 

While I agree that 3/4 on the gauge is worrying(it definitely freaks me out) the most important thing is to have a true digital read out. My 96 will shoot the needle to 3/4 or just above at 204*F, which tends to happen if I'm in a lot of stop/go traffic, doing a lot slow hill climbing, or out wheeling. I don't like it being that high, but it is not a damaging temperature in the least

 

I respectfully very much disagree with the statement that 204 deg. is 3/4 on the gauge. Mine will go to 206 frequently in stop and go without the needle budging at 1/2, and I've got all new temp sensors...

 

have to agree,my gauge sits below half and my temps can go to 215 without needle moving,3/4 would be easily +235 so have it checked

 

I will have to see if the OBD scanner I have can read the coolant temperature. It seems to happen if i am stuck at a light or climbing the 5 story parking garage where I park for work. I may also take it to the rover mechanic a few blocks away and see what he says. I'll keep everyone updated. Thanks everyone for replying.

 

Not to de-rail the thread, but mate I'd replace both of your temp sensors, cause something isn't right there. Respectfully, 3/4 on the gauge is most certainly a concerning sign and doesn't align with 204 deg. I'd just hope it's your dash gauge temp sensor that's bad and not your OBD sensor

 

I've got both temp sensors replaced already, and constantly monitor with my OBD dongle and smart phone. Whether there is a poor connection adding resistance and thus a poor reading, or some other issue, my truck will in fact read 3/4 on the gauge as soon as the truck crests over the 204* mark

My point being that accurate data reading through an ultra gauge or smartphone app is most important, not an arbitrary gauge reading