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Discussion Starter · #1 ·
So.. I'm a mechanic and I bought this 2005 LR3 4.4 V8 knowing that had an overheating issue... I fixed the leaks, put a new water pump, got the radiator fixed (had a little pin hole, nothing bad) replaced some hoses that looked old and non trusty, put new thermostat with the whole housing, flushed the entire system with a water jet, air lifted the system to make sure there was no air pockets. and still overheated on me. Performed a hydrocarbons test to see if there was a head gasket leaking but came out negative and I did it about 5 different times. I tried a new reservoir cap and that seemed to take care of the issue for about an entire week. I parked the vehicle and I didn't use it for another week until now and it overheated again. Before it was blowing hot air out of the vents on full blast but now nothing. Any ideas?
 

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You should try another new tank cap if that cured it first time, if it was aftermarket it's not very strange to fail in no time... if no joy with that and you are certain that the system was bled well try to stop the electro/viscous cooling fan with a rolled up newspaper when the radiator is hot... if you can it means that the viscuous side of the fan is gone and you need new unit cos it must be locked solid with hot radiator as to provide serious air flow then.
 

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Discussion Starter · #4 ·
It's so weird because it almost feels like it overheats when it wants to, it's not all the time but when it does it's at idle or city driving. No leaks deteced so far but I'll try diagnosing the viscous fan.. I guess that's the only thing I haven't tried because well when it starts overheating it kicks in and it's obvious because it really sounds loud, plus that's how I know it's starting to overheat.
 

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NavyDude
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Good luck with this, I’ve been battling this ghost of an issue for 6 months. Same mystery overheating issue that is intermittent and nonsensical.

Mine will perform fine on 113 degree day sitting at idle with AC on full blast while ordering burgers at in-n-out, but will overheat when at a stop sign for 5 seconds, or worse, while going down the road will temp spike for 5 seconds and return to normal operating temps within a few seconds. Makes no dang sense.

Things I’m currently looking at very closely right now:

- ensuring I have a Land Rover genuine thermostat and not an off-brand aftermarket one
-getting a new expansion tank AND cap
-water pump

Would def be interested in helping you track this down as I think it could be a similar problem.
 

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Discussion Starter · #8 ·
Yea, nothing seems to fix the problem at all. My next step will be doing a coolant flush and force all the required coolant into the system and if there is a big air pocket in the system stuck somewhere in there. I'll keep you posted
 

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NavyDude
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Please do. I just did my water pump last night, I've got a new thermostat and housing ready to go in......but some dummy before me stripped the screws. So that'll be a nice little setback.
 

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I'm not a pro at mechanics but the one big issue I had was my bleeder valve on top falling apart from the heat of the coolant over the years. Then the chunks that deteriorated and broke off got stuck in the coolant hoses that were connected to the bleeder valve, so I replaced them. I was not having overheating issues but maybe you have a partial clog in one of the hoses. You may have already replaced these as you mentioned replacing the old and nontrusties.
 

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very disco
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This is a super stale thread

Welcome to the forum tho
 
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