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rover_75
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Discussion Starter #1
Well following the head gasket replacement I still have a problem with overheating.

Done the test 19/7 and engine goin up to 106 on tickover before I switched it off. could here engine boiling but rediator still cold.

fitted new thermostat designed to open at 88 and as the previous thermostat had had its centre removed to allow running without one could i be looking at a blockage somewhere?

bottom rad hose cold all others hot. fan kicks in when air con on. have noticed when on hot air it blows hot on drivers side but only aired in centre and passenger side.

Heeeeeeeeeeeeelp
 

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It does sound like you have a blocked radiator. The stat should be well and truly open by 106C and there should be quite a bit of flow through the rad. The fact that the heater gets hot should rule out air locks or a problem with the pump.
 

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After doing the headgasket I drove the car for about a mile and it started to overheat with the temp guage right at the top. Found that the engine still had a couple of airlocks in it even although I thought I had got rid of the air locks. So, just make sure that there is no air in the system by releasing the air valve and running the engine at a fast idle for a bit to make sure the water is flowing freely.
 

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rover_75
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Discussion Starter #4
Due to the help on this fantastic forum I was aware of the airlock problem and the need to unscrew the bleed screw and allow the water to run freely whilst topping up the bottle.

I was 100% sure it was free of air. I then drained the system as I had added a radiator flush and did the same again and was equally sure I had bled it correctly on each occasion but each time it overheated.

I then ran it with the pressure cap off whilst watching for the temp to rise to see if the fan would kick in at around the 100 mark. The coolant expanded in the tank and began to overflow. I switched off the engine, topped up and replaced the cap and restarted.

Touch wood it now seems fine and was an airlock. All four outlets are blowing hot air whilst only one was previously and the radiator is now getting hot at the top. car seems to be running at low 90s temperature

If anyone reads this thread in the future looking for help with a similar problem following head gasket replacement I have just one bit of advice for you. Bleed, bleed then bleed again.

Dont you just love these K series engines?
 

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What you have achieved by accident is bleeding of the system by the "run it till it boils" method. A lot of people swear by this, but it makes me very nervous!
 

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sometimes if the blades on the back of the pump corrode it wont circulate the water ! not sure if there plastic thins on the pump but im pretty sure there metal , bmws have plastic thins on the back of there water pumps and they break off just sitting there not even spinning !!! i always change the water pump/cambelt when i do any headgasket as using old pump may leak in the near future due to cambelt being tensioned different to before and putting extra load on the pump bearing !! also have you checked the small radiator return pipes/inlet water pipes to make sure there not blocked ???
 

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Hi am having same problem here
Changed thermostat Water pump
Radiator cold temp go up 106 fan kicks in bottom hose cold no circulation water come up radiator cup rising like vulcano it was ok when the thermostat was open just temperature wasn’t going and staying where it should be help pls
 
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