2007 GS450h Cooling & Heating issue

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04-15-15, 04:07 AM

Jensen78

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2007 GS450h Cooling & Heating issue

Hi There

Newbie to this forum

I have a

2007 GS450h

which is misbehaving, The hot air from the heater is currently blowing cold at all times

Work/checks carried out so far :

Removed/checked/replaced engine thermostat - OK
Rebled coolant system - flushed out/checked radiator - flushed out/checked heater matrix
Removed water pump checked impellers and replaced
Removed guts of thermostat and let the coolant system run open curcuit
bypassed electric water pump & valve on opposite side
Engine sniff test for H/G/failure - test results fine fluid stayed blue
All 6 cylinders compression checked - all passed at 155psi or more

I dont believe the Head Gasket(s) are faulty as the block sniffer test carried out came back perfect plus compression tests on all cylinders arew within spec, the radiator & heater matrix are warm at all ends / pipes going in & out, Slight pressure at coolant pressure cap on engine but i believe this is normal due to the coolant system set up.

Car still has plenty of power and engine coolant temperature gauge on dash clocks sits at half way never budges past - Just blows cold air from dash vents -

Driver side vent closest to door window blows slightly warm
Drivers side vent on centre of dash tad warm but cooler than other vent
All passenger side vents freezing cold

Could it be something to do with inside the cabin some sort of electronic valves that work off the dashboard climate control ??

Any ideas would be great as I believe the engine is working as it should unlike what Lexus in Ireland told me - They told me the car needed a new engine at a cost of £7500 euros

Read more: https://www.clublexus.com/forums/hyb...#ixzz3XNJDrwrq

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04-15-15, 06:40 AM

2GSKaizen

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I believe you probably have a bad actuator on the blend door that switches between hot and cold air under the dash. You have checked every possible thing I could think of on the coolant side of things. Usually if the problem is caused by low coolant/ head gasket/ sticking thermostat, you are more likely to get periods of heat that come and go, not a condition where there is never any hot air.