Disco I overheats when the AC is turned on

[ramosr]

My 1996 Disco I overheats when I turn on the air conditioning. The temp gauge runs dead center when the air conditioning is off. The antifreeze level was fine. Shoud I replace the the thermostat? The water pump was replaced about a year ago. Does anyone have any experience with this problem? Thanks...

[landrover77]

Howzit man.
I am not an expert by any means - but when you replace a water pump its common practice to replace the fan clutch - check your fan - does it wobble when stationary or in motion? If so it may be running inefficiently
The thermostat may indeed also be in need of replacing (fairly cheap fix)
-One other mention along these lines is the engine coolant lines/hoses-
your Disco may need a coolant flush (clogging lines/not clogged yet).

When you run the AC the engine requires more energy(= heat) and that
with the other above or other possibilities, could be the reason(s).
For my 95 Disco, it nearly never gets to the half-way marker on the
temp gauge. And I attribute that fact to when I was living in Hawaii-
I had a coolant flush done. The mechanic told me white globs of
(I guess) engine coolant came out during the process. I also replaced the thermostat the same day.

Oh- one more thing, maybe this is something you dont need to be told
but if the engine oil is all crapped up that will = more heat.

[nosivad_bor]

My 1996 Disco I overheats when I turn on the air conditioning. The temp gauge runs dead center when the air conditioning is off. The antifreeze level was fine. Shoud I replace the the thermostat? The water pump was replaced about a year ago. Does anyone have any experience with this problem? Thanks...

are the two condenser fans running when you turn on the air? if not replace those first, but i think really a newradiator would solve all your problems.

check this thread for the same issue

http://www.discoweb.org/forums/showthread.php?t=36819

[ramosr]

Thanks for the replies. Please tell me where the fan condensers are located? Also is there a way to test the fan clutch? My radiator is brand new and I've taken out the thermostat, but the car is still running out when I turn on the A/C. I plan to run a flush if the fan clutch and fan condensers are ok.

[Terrys]

My first thought was also to check to see that the condensor fans were running, but if they're not, don't just run out and replace them until you have checked that the temp switch is actually going on and providing + voltage to the fans.
Also, confirm that your viscous fan clutch is going into lockup as the air temp through the radiator rises. You didn't say what year the truck is, but since it's a D1, it's at least 8 years old, and fan clutches are known to fail WAY before that. Simple way to check is when the temp is up there, rev the engine and confirm the fan is really pulling air, and not just coasting. I'll tell you how I check, but if you do it, do so at your own risk. I actually put my hand accross the blades as it's spinning (My fingers are facing the direction of ratation -Duh-, and if I can easily stop the fan, the clutch is shot. Before you ask, yes, I have all 10 fingers. I have lots of tricks I've picked up in 40 years of working on Land Rovers, many of which I won't share.
Most times when these fan clutches fail, it's because the silicone fluid has leaked out the front valve shaft seal. Easy to confirm that if it's all greasy looking with lots of dirt stuck to the front of the clutch. I have also seen the bimetalic spring fail, so it never actually rotates the vale closed. When this is the case, unhook the outer end and rotate the hooked end of the spring 180s degrees and rehook it to a slot opposite the one it was originally hooked into.
Aftermarket fan clutches are about half the cost of genuine, but last half as long too. A cheap short term , and very simple fix is to take the clutch off the water pump, unbolt the fan blade, and with a small drill, drill down through one of the 1/4 20 holes, STRAIGHT through the clutch, till the drill comes out the front. Now, tap the hole through the body, from the front side, and put a short 1/4 20 bolt back into that hole. That permanantly locks the stator and rotor of the clutch in lockup. This is just a short term fix, because your milage is going to go down, and come fall, you'll have a hard time getting back up to temp.

[nosivad_bor]

the two condenser fans are directly behind the front grill, you can peek beetween the slats in the grill and see them. they are the size of a pie pans side by side.

first step is make sure the fan setting and the air conditioning are off inside the truck. start the truck and with the window down, push the air conditioner button and slider the fan button over to any setting. you should hear the condenser fans turn on. if you dont hear anything get out and look thru the grill and see if they are working.

if nothing then you will need to take the grill off and test the fans to see if they are getting electricity. if they are getting electricity then its likely the fans motors are bad.

after that check the viscous fan as mentioend above.

rob