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I HAVE A NON SUPERCHARGED 2006 RANGE ROVER HSE 4.4L. I HAVE REPLACED THERMOSTAT, WATER PUMP, LOWER RADIATOR THERMOSTAT, FLUSHED ENGINE AND RADIATOR, NEW EXPANSION TANK AND CAP, TEMPERATURE SENSORS, ENGINE OIL COOLER AND HOSES.

I CAN NOT UNDERSTAND WHY I'M STILL HAVING OVERHEATING PROBLEMS. IT APPEARS THAT I AM NOT GETTING ADEQUATE CIRCULATION. I CAN REMOVE THE TOP RADIATOR HOSE AND FEED WATER THROUGH THE TOP HOSE. NORMALLY THERE WOULD BE A RATHER HEALTHY FLOW OF WATER COMING OUT OF THE TOP RADIATOR HOSE HOUSING. HOWEVER IT TENDS TO FLOW SLOWLY. FLOWS VERY GOOD OFF THE VEHICLE AND PRESSURE TESTED WELL.

AT IDLE THE TEMPERATURE BEGINS TO RISE AND WILL GET AS HIGH AS 253 DEGREES. I CAN TAKE A WATER HOSE AND SPRAY THE ENTIRE THERMOSTAT COVER ASSEMBLY (LR007603) AND IT WILL IMMEDIATELY COOL DOWN TO AS LOW AS 80 DEGREES. ONCE TAKEN OFF THE TEMP RISE STARTS AGAIN. COOLING FANS FUNCTION AND START AS THEY SHOULD.

IS IT POSSIBLE THAT THE ENTIRE THERMOSTAT COVER ASSEMBLY HOUSING IS BAD AND CREATING THIS PROBLEM?:help

I HAVE DONE ALL I CAN THINK OF TO DO AS OF THIS POINT. HEADS AND HEAD GASKETS ARE GOOD, NO LEAKING THERE.

DOES ANYONE HAVE ANY IDEAS OR SUGGESTIONS? ANY INFO WOULD BE GREATLY APPRECIATED.
 

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Perhaps the issue is with the radiator itself. Clogged tubes will restrict the flow. I take it overheating was the initial problem. Did you purchase this Rover new & has the radiator been maintained? I ask because perhaps a previous owner didn't keep up with the maintenance. It sounds like there is a restriction and you have replaced almost everything other than the radiator...
 

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Sounds like a bad radiator not thermostat.
Dave
 

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I have the same problem with my 2006 RR. I have done everything and I am still having the overheating problem. Now I am thinking about a head gasket job

To be correct, I brought that car with that problem from the previous owner.

Now, my dilemma is either do the head gasket job or replace the engine. it just happens that I have another 2006 RR which runs perfectly.

I just love the car. I will keep you updated.
 

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There are several ways to test a head-gasket for failures.

A chemical test will turn a CO2 sensitive fluid a different color if CO2 is found in your cooling system.

You can pull your spark plugs and pressurize your coolant system for 24 hours. If you turn the motor over and there is coolant shooting out of the spark plug tubes, you have a slow leak.

You can inspect plugs for signs of coolant.

You can monitor cooling system pressure and thermostat opperation via a pressure guage and scan tool....

Point is, have someone that really knows their stuff test the head gaskets a few different ways before going down this road.

Also check airflow over the radiator. Put a fan in front of the radiator and see if temps come down at idle. If this solves the issue you have a weak fan or a clogged/weak radiator.

If you rev the engine to 2000 rpms while sitting still and the temps come down, you have a flow issues. Weak water pump, restriction in the system, etc.

If the system starts to overheat after a few minutes and nothing seems to bring the temperatures back down you may have a headgasket issue or a stuck thermostat.

The thermostat should be replaced if it's been subjected to high temperatures. They are simple springs and wax valves and spring metal can loose its memory with high temperatures. A new thermostat may be opening incorrectly but you'll be able to see that with a scan tool.
 

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There are several ways to test a head-gasket for failures.

A chemical test will turn a CO2 sensitive fluid a different color if CO2 is found in your cooling system.

You can pull your spark plugs and pressurize your coolant system for 24 hours. If you turn the motor over and there is coolant shooting out of the spark plug tubes, you have a slow leak.

You can inspect plugs for signs of coolant.

You can monitor cooling system pressure and thermostat opperation via a pressure guage and scan tool....

Point is, have someone that really knows their stuff test the head gaskets a few different ways before going down this road.

Also check airflow over the radiator. Put a fan in front of the radiator and see if temps come down at idle. If this solves the issue you have a weak fan or a clogged/weak radiator.

If you rev the engine to 2000 rpms while sitting still and the temps come down, you have a flow issues. Weak water pump, restriction in the system, etc.

If the system starts to overheat after a few minutes and nothing seems to bring the temperatures back down you may have a headgasket issue or a stuck thermostat.

The thermostat should be replaced if it's been subjected to high temperatures. They are simple springs and wax valves and spring metal can loose its memory with high temperatures. A new thermostat may be opening incorrectly but you'll be able to see that with a scan tool.
How do I test thermostat on the rrs it is not a one piece.
 

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There are several ways to test a head-gasket for failures.

A chemical test will turn a CO2 sensitive fluid a different color if CO2 is found in your cooling system.

You can pull your spark plugs and pressurize your coolant system for 24 hours. If you turn the motor over and there is coolant shooting out of the spark plug tubes, you have a slow leak.

You can inspect plugs for signs of coolant.

You can monitor cooling system pressure and thermostat opperation via a pressure guage and scan tool....

Point is, have someone that really knows their stuff test the head gaskets a few different ways before going down this road.

Also check airflow over the radiator. Put a fan in front of the radiator and see if temps come down at idle. If this solves the issue you have a weak fan or a clogged/weak radiator.

If you rev the engine to 2000 rpms while sitting still and the temps come down, you have a flow issues. Weak water pump, restriction in the system, etc.

If the system starts to overheat after a few minutes and nothing seems to bring the temperatures back down you may have a headgasket issue or a stuck thermostat.

The thermostat should be replaced if it's been subjected to high temperatures. They are simple springs and wax valves and spring metal can loose its memory with high temperatures. A new thermostat may be opening incorrectly but you'll be able to see that with a scan tool.
I changed the themostat housing ,I it overheats while driving , if I stop cools right down. i tried to bleed system to no avail. I do have a leak in the radiator so maybe part of the issue. Bought a leak sealer will try tomorrow. any advice is welcome , New radiator not a option.
 
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