Hey guys,

So I was driving to work this cold Tulsa morning and noticed that I wasn't getting warm. I realized my A/C was blowing cold air. I turned the temp up to high, down to 84, turned it off/on, and it was still the same thing. Econ is not engaged.

I already did HGs successfully, but I am admittedly a noob when it comes to working on A/C systems. If anyone wouldn't mind explaining how the heating system works in the Disco and what first steps I should take to diagnose my problem, I would be very appreciative.

Thanks!

JC

 

1st, i am absolutely no expert at auto heating /ac systems (or really anything auto)
but the first thing to check is circulation through the heater core. make sure you are not clogged. if you have the stock routing and coolant circulation, you should always have a steady flow through the heater core (bypass system does not allow for any other option). your controls would then direct the system to and how much your fan is blowing that heat.
air is blended as needed and blown by the electric fan. so if it be blowing, the fan be working. could be blending cold air with cold air (lack of heater core circulation)
next, is it even blending? it has a blending actuator. it could be bad. its a little electric motor.
then there is the possibility of electrical issues........


edit...found this little explanation of system http://www.howacarworks.com/basics/h...n-systems-work

 

So, to check the circulation, do I just get the car warm, turn the engine off, and unplug one of the lines to see if there is coolant in it? Or do i just touch the lines while the engine is running to see if they're warm?

 

if you don't have a big air bubble in the system......you can just feel the two little lines as truck is running. both should get steady flow of warm coolant travelling through. if you have air in the system your core will have trouble producing heat. you normally hear the waterfall/trickle sound at the core, if air is the culprit.

 

Okay. I did HG's about a year ago and haven't lost any coolant since, so I doubt there's an air bubble (unless they can work their way in by some other means). It was producing zero heat, so I'm wondering if it is more likely the blending actuator has gone out. I have to valet my D2 at work so I can't really look at it until after work, but I'll check out the lines and report back once I'm home.

 

good deal. and yes you can get air in the system through other means, not just head gasket. usually it is a 2 way leak (air in water out) but i sucked air from a bad bleed screw and never saw a loss of coolant.....just an fwiw.
now, get back to work!

 

So, an update--I overheated yesterday on my way home from work. I caught it pretty quick, so I don't think any new damage was done. Apparently my heater going out was not a result of a blockage in the heater core but rather a lack of coolant to push into the heater core.

'Tain't good, as they say. I took my truck down to O'Brien Performance Auto in downtown Tulsa (stand up guys, great Rover knowledge/enthusiasm, a little pricey) to have them check it out. My truck won't fit in my garage, and it's dark when I leave my house in the morning and dark when I get home, so I can't really do much worthwhile inspecting. Looks like I might end up with a nice Christmas break project though =/

I'll update with what they say at O'Briens. The leak looks like it's coming from the front cover area, but I couldn't see it actively spraying anywhere. The puddle under my car this morning was more under the cats than anything. I lost at least a quart of coolant getting over the course of a 10 minute drive home/sitting in my driveway all night. I did HGs last year, didn't have a cracked block at the time, no slipped sleeves, all looked good. Any insights you guys might have would be appreciated.

 

Front cover is a common water leak, requires droping the oil pan. You might want to concider the shape of your oil, water pumps snd timing chain while your there?

 

you might get lucky if its up front...could be just a water pump.
it has a built in weep hole warning system. (the inner seal starts failing and allows coolant past it, that coolant is then expelled through the weep hole......the driver is then supposed to notice this coolant leak/loss and replace the pump) if you didn't notice that your coolant was low, you probably would not have noticed the dripping either. just one scenario.
but . as Drow. said^^ front cover is common place.
throttle body heater is another...this would allow the coolant leak to puddle under the cat too. running over top of the valve cover to the back

 

I doubt it's the throttle body heater plate--we replaced that with the HG job. That being said, one thing i did think was funny after we did the HGs, I noticed a tiny bit of coolant had leaked around from behind the drivers side valve cover. You could see it accumulated on the rubber gasket tab that sticks out, and the trail along the gasket from behind the VC. It never dripped or anything when I saw it and I had no visible coolant loss in the reservoir so I didn't think much of it. It didn't appear to be seeping out from the gasket, either. It was just an odd thing I didn't (want to) think much of.