LR3 4.4 Overheating Issue
Maybe I am just paranoid, still working on my LR3 cooling system. Flushed the front heater core and about to do the rear. The issue I am having is that it overheats after maybe 15 minutes of driving and coolant boils out of the reservoir. There is no smoke, no milky oil and no bubbles in the coolant. I have performed a combustion leak test and the fluid stayed blue. Is there any other symptom to diagnose a bad head gasket or is there just air in the system? No rear heat at the moment but I am not sure if its air or if its clogged, I am about to try and flush it tho. Maybe a clogged radiator? Not sure how to diagnose that.
I don't remember if the heater core is before or after the thermostat but that could be a hint.
Mudding
Joined: Jan 2022
Posts: 161
Likes: 23
From: Michigan
I’m not an expert on mixed coolant types, defer to others.
as for the vacuum fill, Indrew -25psi($) on the systems. Let it sit like that for a minute Tony ensure it would hold a vacuum. Once confirmed I filled the system with coolant.
The rubber hoses did get very flat, nothing to worry about. The coolant stopped flowing once it filled the system (still about -3psi of vacuum when coolant stopped flowing). I squeezed the hoses to help the process along. Added about 3/4” of coolant to the reservoir tank after driving to get it to temp.
as for the vacuum fill, Indrew -25psi($) on the systems. Let it sit like that for a minute Tony ensure it would hold a vacuum. Once confirmed I filled the system with coolant.
The rubber hoses did get very flat, nothing to worry about. The coolant stopped flowing once it filled the system (still about -3psi of vacuum when coolant stopped flowing). I squeezed the hoses to help the process along. Added about 3/4” of coolant to the reservoir tank after driving to get it to temp.
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Overlanding
Joined: Jun 2024
Posts: 20
Likes: 1
From: Kansas
Have you tested the thermostat? Overheating quickly is a sign of a thermostat, and has similar symptoms of a clogged radiator. See if the radiator gets hot when it overheats or if its still cool/lukewarm. You could use a laser thermometer to see where there's hot or cold coolant and locate hot spots. If its hot it means its getting coolant cycled through the motor, if its closer to ambient than the motor temp it means its not getting coolant cycled through the motor.
I don't remember if the heater core is before or after the thermostat but that could be a hint.
I don't remember if the heater core is before or after the thermostat but that could be a hint.
If your replacing it anyway, it may be a good idea to test the new and the old one just to confirm if it was the culprit. Takes less than 15 minutes to do and you will know exactly what caused it. Plus if its a working thermostat you can keep it as a spare for yourself or another rover.
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Overlanding
Joined: Jun 2024
Posts: 20
Likes: 1
From: Kansas
Ok it ended up being a water pump, so I replaced the water pump, radiator, thermostat housing and did a vacuum fill and all seems to be running smoothly. No overheating, just a code for bank 1 and bank 2 too lean. Would that be a MAF sensor?
Glad you were able to fix it!
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