Temp light came on, now sitting on side of road;)
Mudding
Joined: Oct 2009
Posts: 192
Likes: 0
From: Windsor, Ontario
Lordmorpheus,
This one's got my head scratching. However I cannot see how heat seating has anything to do with overheating. I worked as a VW mechanic through college (many years ago lol) so I do have a good idea of how the cooling system works.
How I explained to bleed the system is how I do it every time. Not once did I ever have a problem. Something is missing here........I can't quite put my finger on it yet.....
This one's got my head scratching. However I cannot see how heat seating has anything to do with overheating. I worked as a VW mechanic through college (many years ago lol) so I do have a good idea of how the cooling system works.
How I explained to bleed the system is how I do it every time. Not once did I ever have a problem. Something is missing here........I can't quite put my finger on it yet.....
Pro Wrench
Joined: May 2010
Posts: 1,918
Likes: 86
From: St Louis MO
I am scratching my head too. I am just thinking and typing out loud here...
When she turned off the heat on the original post, how did she do that? On a D2 there is no "heat" button. Did she turn off the whole HVAC system, or lower the temperature settings enough to engage the A/C and subsequently the condenser fan? Possible problem with the fan clutch or radiator fan, and the condenser fan operating kept the radiator cool enough? This time, it didn't begin to overheat on the gauge until "econ" was selected, which turns off the A/C. The condenser fan engages as needed when the A/C is on, but should also engage when at a certain coolant temperature...
When she turned off the heat on the original post, how did she do that? On a D2 there is no "heat" button. Did she turn off the whole HVAC system, or lower the temperature settings enough to engage the A/C and subsequently the condenser fan? Possible problem with the fan clutch or radiator fan, and the condenser fan operating kept the radiator cool enough? This time, it didn't begin to overheat on the gauge until "econ" was selected, which turns off the A/C. The condenser fan engages as needed when the A/C is on, but should also engage when at a certain coolant temperature...
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
1. As a reminder, on the D2, the coolant flows in the heater core 100% of the time the truck is running. There is not a valve that changes or shuts off the flow. Having the heat on at all, or on max, makes no change in how much coolant is in the system. Turning on the heat simply changes the blend doors of the heater blower unit. Now this does not hurt adding coolant either.
2. The heater is getting warm ONLY because hot coolant is inside. But I suspect that is when the main thermostat is closed, so the main flow is blocked, and the only way to flow is via the hater core. So the water pump forces it in there. BUT when the thermostat opens, the path thru the engine is so much lower "resistance" that virtually all the coolant goes thru engine and none goes thru heater core.
3. This could be due to heater core being restricted. I suggest owner remove both hoses going toward heat under the hood, and attach a garden hose and flush them out. You would want to squirt water in the hose that is close to the left side of the water pump, when you are standing in front of truck.
4. Normally, you were hearing coolant with bubbles. This could have allowed gunk to build up inside the heater core over a long period of time. Now you hear no bubbles. That either means coolant is full, or so low that nothing comes through heater core. Would be a good idea to slightly open the bleed screw and let truck push out some more coolant (you will add some at same time). Need to be sure there is no trapped air.
5. When idling in park, hold a wimpy plastic bag, like from WalMart, in front of radiator. It should pull toward radiator. Was belt route correct to start with?
6. When truck overheats, where is gauge going?
7. I would point out that with heater core slowing water flow, that will also slow the flow of water around the thermostat when it is closed. This will delay it reaching temp to open, meanwhile engine heat climbs. Of course, if heater core has gunk in it, radiator needs a flush as well, but may have just gotten one.
2. The heater is getting warm ONLY because hot coolant is inside. But I suspect that is when the main thermostat is closed, so the main flow is blocked, and the only way to flow is via the hater core. So the water pump forces it in there. BUT when the thermostat opens, the path thru the engine is so much lower "resistance" that virtually all the coolant goes thru engine and none goes thru heater core.
3. This could be due to heater core being restricted. I suggest owner remove both hoses going toward heat under the hood, and attach a garden hose and flush them out. You would want to squirt water in the hose that is close to the left side of the water pump, when you are standing in front of truck.
4. Normally, you were hearing coolant with bubbles. This could have allowed gunk to build up inside the heater core over a long period of time. Now you hear no bubbles. That either means coolant is full, or so low that nothing comes through heater core. Would be a good idea to slightly open the bleed screw and let truck push out some more coolant (you will add some at same time). Need to be sure there is no trapped air.
5. When idling in park, hold a wimpy plastic bag, like from WalMart, in front of radiator. It should pull toward radiator. Was belt route correct to start with?
6. When truck overheats, where is gauge going?
7. I would point out that with heater core slowing water flow, that will also slow the flow of water around the thermostat when it is closed. This will delay it reaching temp to open, meanwhile engine heat climbs. Of course, if heater core has gunk in it, radiator needs a flush as well, but may have just gotten one.
Last edited by Savannah Buzz; Nov 11, 2011 at 09:37 PM.
Mudding
Joined: Oct 2009
Posts: 192
Likes: 0
From: Windsor, Ontario
Good point Buzz.
There could be gunk from "Stop Leak" in the bottle crap in the heater core and other parts of the system. If they touch both hoses from the heater core they should have the same temperature (simple test to check if the coolant if flowing good). Other than that.....someone familiar with LR needs to look at this Disco. It could be something really small and stupid. I just don't know what to type anymore......
There could be gunk from "Stop Leak" in the bottle crap in the heater core and other parts of the system. If they touch both hoses from the heater core they should have the same temperature (simple test to check if the coolant if flowing good). Other than that.....someone familiar with LR needs to look at this Disco. It could be something really small and stupid. I just don't know what to type anymore......
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Three Wheeling
Joined: Jun 2011
Posts: 60
Likes: 0
From: Washington State
He just read all your post, said hewillcheck it out again tomorrow. bTW the first time it overheated it may not have helped to turn the heat off, and I just thought it did. Because I was parked on the side of the road when turning the heat off. I do know this. It doesn't overheat as easily when the heat stays off, that is how I made it home. But also no hot air was coming out for me at max defrost and fan.
This is what I do when turning on heat. I hit either the auto button or the defrost button and then set temp. The button I use to turn it off is the one with the circle and line in it.. Yes I know I sound like a complete idiot.
He has bled it again and got it working normally so it seems. He said he can hear the coolant rushing thru when reving up to 1500rpms but it doesn't sound like the gurgling it did before, is that suppose to happen. Have a good night all. Thanks again.
This is what I do when turning on heat. I hit either the auto button or the defrost button and then set temp. The button I use to turn it off is the one with the circle and line in it.. Yes I know I sound like a complete idiot.
He has bled it again and got it working normally so it seems. He said he can hear the coolant rushing thru when reving up to 1500rpms but it doesn't sound like the gurgling it did before, is that suppose to happen. Have a good night all. Thanks again.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
Am worried there might be Dexcool sludge, if so, it builds up as a mud that will pass stuff, but keeps reducing the cross sectional area of the pipes, like mud building up in a pipe, you started with a four inch drain, now you are down to just a shaft of daylight at the top. It will pass water, just not in volume. Radiator could be problem also. We have not even gotten to can truck drive at 45 mph without overheat. May still have too much air inside.
Both heater pipes being same temp would be good, but a flush would still be in order. Then you can see if it is free-flowing.
I hate that your testing is depending on the coolant gauge or over heat light. If you had one of the scanners, you could tell the temp was risisng before it got too hot, and stop the test and do more work. Don't want you to seriously overheat the engine again and again.
Both heater pipes being same temp would be good, but a flush would still be in order. Then you can see if it is free-flowing.
I hate that your testing is depending on the coolant gauge or over heat light. If you had one of the scanners, you could tell the temp was risisng before it got too hot, and stop the test and do more work. Don't want you to seriously overheat the engine again and again.
Last edited by Savannah Buzz; Nov 11, 2011 at 10:09 PM.
Pro Wrench
Joined: May 2010
Posts: 1,918
Likes: 86
From: St Louis MO
Thinking/typing aloud again...
But, having the heat on max, DOES force air over the heater core, cooling the coolant inside the heater core, which is then acting like a small radiator.
From memory of the D2 cooling system: At cold engine start, the coolant is circulated through the heater core and engine only. When the coolant reaches the correct temperature, it begins to circulate through the radiator.
Agreed, just to verify no restriction in heater core. When I replaced the engine in my newly purchased Disco, I stuck the garden hose directly to the heater core pipes both ways, to make sure all junk was flushed.
Something I have done in the past, as the coolant bleed screw is the highest in the system.
Make sure HVAC is set to max heat, or economy, to ensure the condenser fan is not engaging.
1. As a reminder, on the D2, the coolant flows in the heater core 100% of the time the truck is running. There is not a valve that changes or shuts off the flow. Having the heat on at all, or on max, makes no change in how much coolant is in the system. Turning on the heat simply changes the blend doors of the heater blower unit. Now this does not hurt adding coolant either.
2. The heater is getting warm ONLY because hot coolant is inside. But I suspect that is when the main thermostat is closed, so the main flow is blocked, and the only way to flow is via the hater core. So the water pump forces it in there. BUT when the thermostat opens, the path thru the engine is so much lower "resistance" that virtually all the coolant goes thru engine and none goes thru heater core.
3. This could be due to heater core being restricted. I suggest owner remove both hoses going toward heat under the hood, and attach a garden hose and flush them out. You would want to squirt water in the hose that is close to the left side of the water pump, when you are standing in front of truck.
4. Normally, you were hearing coolant with bubbles. This could have allowed gunk to build up inside the heater core over a long period of time. Now you hear no bubbles. That either means coolant is full, or so low that nothing comes through heater core. Would be a good idea to slightly open the bleed screw and let truck push out some more coolant (you will add some at same time). Need to be sure there is no trapped air.
Make sure HVAC is set to max heat, or economy, to ensure the condenser fan is not engaging.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
more discussion:
re: But, having the heat on max, DOES force air over the heater core, cooling the coolant inside the heater core, which is then acting like a small radiator.
True, but it does not make as large a difference that a D1 has when a slug of water from inisde the off line heater core is added to the system, and the additional square inches are added as well. And it does not change volume of coolant.
RE: From memory of the D2 cooling system: At cold engine start, the coolant is circulated through the heater core and engine only. When the coolant reaches the correct temperature, it begins to circulate through the radiator.
We agree, AND if the heater core is restricted, the path thru the radiator will drop the pressure so much that the flow thru the restricted heater core will fizzle out. So it gets cold, then hot, then cold as themostat cycles. Another problem is that when the main thermostat is closed, the hot coolant circulates past it by four small sampling holes, to warm it back up to operate again. That flow rate might change quite a bit if heater core was partially obstructed, resulting in thermostat taking too long to open, engine getting hotter than it should.
RE: Make sure HVAC is set to max heat, or economy, to ensure the condenser fan is not engaging.
Actually, good idea to do it both ways. My PO reverse wired condenser fans and I would over heat at idle. So 1 fan or all fans, air should move toward engine block.
IMHO it would be a good day to flush heater core AND main radiator, reverse direction. For minutes, not seconds. And if handy with temporray plumbing, just bypass the core for testing if blockage is still suspected.
re: But, having the heat on max, DOES force air over the heater core, cooling the coolant inside the heater core, which is then acting like a small radiator.
True, but it does not make as large a difference that a D1 has when a slug of water from inisde the off line heater core is added to the system, and the additional square inches are added as well. And it does not change volume of coolant.
RE: From memory of the D2 cooling system: At cold engine start, the coolant is circulated through the heater core and engine only. When the coolant reaches the correct temperature, it begins to circulate through the radiator.
We agree, AND if the heater core is restricted, the path thru the radiator will drop the pressure so much that the flow thru the restricted heater core will fizzle out. So it gets cold, then hot, then cold as themostat cycles. Another problem is that when the main thermostat is closed, the hot coolant circulates past it by four small sampling holes, to warm it back up to operate again. That flow rate might change quite a bit if heater core was partially obstructed, resulting in thermostat taking too long to open, engine getting hotter than it should.
RE: Make sure HVAC is set to max heat, or economy, to ensure the condenser fan is not engaging.
Actually, good idea to do it both ways. My PO reverse wired condenser fans and I would over heat at idle. So 1 fan or all fans, air should move toward engine block.
IMHO it would be a good day to flush heater core AND main radiator, reverse direction. For minutes, not seconds. And if handy with temporray plumbing, just bypass the core for testing if blockage is still suspected.
Recovery Vehicle
Joined: May 2009
Posts: 1,191
Likes: 28
From: Charlotte, NC
Then I am most concerned that you have larger issues. If coolant is full, AND remains so, generally only a few things cause overheat:
1. Water rushing noise may have indicated long term head gasket leak, but surely you would have seen other things, like water in oil when changed, oil in coolant jug (scum), plenty of other overheating, white smoke from exhaust, smell of coolant. Bubbles can also just be trapped air, which can be purged.
2. Overheating with coolant can indicate poor water pump, blocked radiator outside (mud, trash, leaves), blocked radiator inside (calcium buildup from using tap water instead of distilled water). This is normally at moderate speed and slow speed.
3. At low speeds, overheat can be caused by worn out fan clutch. It has to "engage" to provide more cooling when hotter than normal, if it doesn't, temp climbs. When engine warmed up, AND off, spin fan by hand. Should feel somewhat stiff, maybe spin 1/2 to 1 revolution. If it "freewheels" the fluid inside the clutch has dripped out, and replacement is the way to go. Write up in tech section.
4. Cracked block.
5. Thermostat. D2 has unique thermostat in the plumbing. Has some little holes in it that sample the hot water to make it work. When they clog, the sampling takes longer and longer and it heats up more and more. See https://landroverforums.com/forum/at...mostat-005-jpg
1. Water rushing noise may have indicated long term head gasket leak, but surely you would have seen other things, like water in oil when changed, oil in coolant jug (scum), plenty of other overheating, white smoke from exhaust, smell of coolant. Bubbles can also just be trapped air, which can be purged.
2. Overheating with coolant can indicate poor water pump, blocked radiator outside (mud, trash, leaves), blocked radiator inside (calcium buildup from using tap water instead of distilled water). This is normally at moderate speed and slow speed.
3. At low speeds, overheat can be caused by worn out fan clutch. It has to "engage" to provide more cooling when hotter than normal, if it doesn't, temp climbs. When engine warmed up, AND off, spin fan by hand. Should feel somewhat stiff, maybe spin 1/2 to 1 revolution. If it "freewheels" the fluid inside the clutch has dripped out, and replacement is the way to go. Write up in tech section.
4. Cracked block.
5. Thermostat. D2 has unique thermostat in the plumbing. Has some little holes in it that sample the hot water to make it work. When they clog, the sampling takes longer and longer and it heats up more and more. See https://landroverforums.com/forum/at...mostat-005-jpg
He's gonna have to get under there and look at those head gaskets, throttle body heater plate, the usual suspects. Land Rover head gaskets suck, actually their gaskets in general suck.
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Three Wheeling
Joined: Jun 2011
Posts: 60
Likes: 0
From: Washington State
After re bleeding he drove it for 10 miles, with no problems, heater works great. One thing though. Still have the water noise under the dash. Does there have to be something wrong with it, with that noise.
No water I the oil, no white smoke. I think I will find one of those scanners Buzz was talking about.
No water I the oil, no white smoke. I think I will find one of those scanners Buzz was talking about.
