Over heating
#1
01-31-2015, 09:56 PM
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Over heating
I have a 2002 Land Rover discovery II and it leaks out of the presure tank over flow. Had a pressures test done all good did a gas pressure test liquid stayed blue indicating no head gasket leak. Changed the thermostats, the upper hoses are hot but the lower hose from the rad to the thermo is cold. Fan turns and temp gauge shows normal. After about 15 mins the pressure tank bubbles and blows out the overflow and also no heat
PLEASE HELP
PLEASE HELP
#2
01-31-2015, 10:16 PM
Do you have the bleed valve on the T connector on the radiator hose. I had the same over heating issue were the truck would not register hot on the dash guage, but would smell hot and the top hoses would be alot hotter than the bottom radiator hose. Mine was due to air in the line and not properly bled. Hope that helps
#4
02-01-2015, 06:58 PM
#5
02-02-2015, 11:18 AM
Rock Crawling
Sounds like air in the cooling loop to me. Especially if you have let it boil out and get pretty low. The only time I have ever seen mine actually bubble in the overflow tank was when I had taken the cap off while hot one time and it gushed a ton of coolant out. For awhile after that it would bubble in the overflow after it got hot, it would try to run hot too. After getting all the air out and plenty of coolant back in it it stopped.
#6
02-16-2015, 11:17 AM
Overlanding
A few mysteries solved by applying simple physics to the approach.
As far as bleeding the system and the waterfall noise in the passenger compartment. Lets remember that when hot/under pessure every cooling system becomes a closed system after the first time you heat it up. But when cold you can break that seal which is fine because gravity keeps the fluid levels equal thus not allowing air into the system. much the same way the trap on the sink in your house which stops methane gasses from getting into your home.
Now for why the land rover way to bleed the system is the only way to do it right and its simple.
This applys to both D1's and D2's..
If you look at a picture of the truck from the side and draw a vertical line across it at level with the top of the radiator. you will notice that both the heater core and the bleed cap sit above plane with the rest of the system.
As for the heater core and the water fall noise this is do to an air pocket that gets trapped in the part of the heater core that is above plane withth the rest of the system. That said if you have even a pin hole or loose clamp bad head gasket ETC.ETC. Air is making its way into what should be a closed system. With air getting into the system it will make its way to the top of the heater core causing the water fall noise. Most likely cause for this is a pin hole in the heater core itself which is very common for all older cars. I recommend bypassing the heater core by pulling the hoses off the fire wall and hooking them together. this will give a good idea of weather the heater core is bad or not. pin holes in the heater core can cause an over heating problem to resurface moths later after you have done tons of work and spent tons of money replacing everything else to no avail.
As far as bleeding the system you must have a bleed orafice above the radiator if you dont have the factory one in the rad hose that runs over the cowl or in the T fitting that connects the 3 hoses to the left of the AC compessor you need to get the oem parts or plumb one in to either of those locations they are clearly pointed out on diagrams in the rave just look up cooling system drain and refill.
Now for simple physics if you take a clear hose and fill it water stand at the top of a stair case and have another at the bottom with a pole to hold the hose end up to same level as the person at the top the sairs the water at both ends of the hose will be level on the same spacial plane. if you were to have a third person hold the hose up in the center to same hieght then you would have a bubble in the middle. Trust me it never fails.
Now apply this Simple theory to your cooling system if part of the heater core sits above the rest of the cooling system then you have the potential to get an air bubble in the heater core this air bubble can migrate or split into 2 or 3 or more bubbles. Now one of those bubble can migrate to the thermostat housing and get cuaght in there thus allowing the thermostat to cool down and close up on you.
So when the rave tells you to unclip the hose from the top of the cowl and open the bleeder and raise the overlow tank. that opens the system at it's highest piont and puts the over flow into a potision to gravity feed and push any air out of the system.
This was an oversite in the heater design location and can only be rectified by bleeding the system the way they tell you. Or to or bypass or relocate the heater core lower in the system.
If you can have your system pressureized and watch for leak down if it does find it. leaks dont allway present them selves by fliud spilling out some of those can actually close up as the system heats up. Remember simple physics when thins get hot they expand thus closing gaps. but when the system cools down it can suck air in. Which common sense tells me is the cuase of alot of overheating and cooling system problems withese cars.
Last but not least use THE ORANGE COOLANT I cannot stress this enough. These are all aluminum motors and having owned BMW's before. Remember these motors were originally desinged and built by bosch. Which are most notable for there formula1 engines. that saud they are way over engineered for a utility aplication so treat the motor like its from a porsche or beemer. To get the performace specs they were looking for in an SUV the engine runns hotter and the orange coolant is desined to haddle that heat and keap the motor at its safe running temperature. The green stuff does not do it. remember these motors were disined by race engineers so the normal peramitters do not apply.
I hope this helps. I love this forum it has been supper helpful so I hope this helps others understand the cooling sytem better.
As far as bleeding the system and the waterfall noise in the passenger compartment. Lets remember that when hot/under pessure every cooling system becomes a closed system after the first time you heat it up. But when cold you can break that seal which is fine because gravity keeps the fluid levels equal thus not allowing air into the system. much the same way the trap on the sink in your house which stops methane gasses from getting into your home.
Now for why the land rover way to bleed the system is the only way to do it right and its simple.
This applys to both D1's and D2's..
If you look at a picture of the truck from the side and draw a vertical line across it at level with the top of the radiator. you will notice that both the heater core and the bleed cap sit above plane with the rest of the system.
As for the heater core and the water fall noise this is do to an air pocket that gets trapped in the part of the heater core that is above plane withth the rest of the system. That said if you have even a pin hole or loose clamp bad head gasket ETC.ETC. Air is making its way into what should be a closed system. With air getting into the system it will make its way to the top of the heater core causing the water fall noise. Most likely cause for this is a pin hole in the heater core itself which is very common for all older cars. I recommend bypassing the heater core by pulling the hoses off the fire wall and hooking them together. this will give a good idea of weather the heater core is bad or not. pin holes in the heater core can cause an over heating problem to resurface moths later after you have done tons of work and spent tons of money replacing everything else to no avail.
As far as bleeding the system you must have a bleed orafice above the radiator if you dont have the factory one in the rad hose that runs over the cowl or in the T fitting that connects the 3 hoses to the left of the AC compessor you need to get the oem parts or plumb one in to either of those locations they are clearly pointed out on diagrams in the rave just look up cooling system drain and refill.
Now for simple physics if you take a clear hose and fill it water stand at the top of a stair case and have another at the bottom with a pole to hold the hose end up to same level as the person at the top the sairs the water at both ends of the hose will be level on the same spacial plane. if you were to have a third person hold the hose up in the center to same hieght then you would have a bubble in the middle. Trust me it never fails.
Now apply this Simple theory to your cooling system if part of the heater core sits above the rest of the cooling system then you have the potential to get an air bubble in the heater core this air bubble can migrate or split into 2 or 3 or more bubbles. Now one of those bubble can migrate to the thermostat housing and get cuaght in there thus allowing the thermostat to cool down and close up on you.
So when the rave tells you to unclip the hose from the top of the cowl and open the bleeder and raise the overlow tank. that opens the system at it's highest piont and puts the over flow into a potision to gravity feed and push any air out of the system.
This was an oversite in the heater design location and can only be rectified by bleeding the system the way they tell you. Or to or bypass or relocate the heater core lower in the system.
If you can have your system pressureized and watch for leak down if it does find it. leaks dont allway present them selves by fliud spilling out some of those can actually close up as the system heats up. Remember simple physics when thins get hot they expand thus closing gaps. but when the system cools down it can suck air in. Which common sense tells me is the cuase of alot of overheating and cooling system problems withese cars.
Last but not least use THE ORANGE COOLANT I cannot stress this enough. These are all aluminum motors and having owned BMW's before. Remember these motors were originally desinged and built by bosch. Which are most notable for there formula1 engines. that saud they are way over engineered for a utility aplication so treat the motor like its from a porsche or beemer. To get the performace specs they were looking for in an SUV the engine runns hotter and the orange coolant is desined to haddle that heat and keap the motor at its safe running temperature. The green stuff does not do it. remember these motors were disined by race engineers so the normal peramitters do not apply.
I hope this helps. I love this forum it has been supper helpful so I hope this helps others understand the cooling sytem better.
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