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shakeym35

Over heating

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Hi all I’ve got a over heating issue.  A few days ago my engine temperature over heated due to not much water in system.  So I topped the water expansion tank.  Now the top coolent hose on passenger side gets hot but the bottom coolent hose on drivers side stays cold also radiator stays cold. Engine still continues to overheat.  Seems like some sort of a blockage.  Any ideas and suggestions would be appreciated. Thanks 

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I would say it's air in the system. Can be bled relatively easily via bleed screw on top of thermostat housing. If this is seized (as they usually are) try doing from the top hose of the radiator if possible with the car parked on an incline. 

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2 hours ago, Lloydy said:

I would say it's air in the system. Can be bled relatively easily via bleed screw on top of thermostat housing. If this is seized (as they usually are) try doing from the top hose of the radiator if possible with the car parked on an incline. 

 

With the car facing upwards.:P

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7 hours ago, duncan-uk said:

Thermostat not opening?


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Today I spent some time around the cooling system.  I began with removing the thermostat. 

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Okay guys appreciate the suggestions.    So today I began looking around the cooling system.  Firstly removed the thermostat then removed the coolent pipes from radiator and other accessible areas.  I then flushed all the system with the garden hose.    The radiator had no blockage as water was flowing free from top through to the bottom... 

 

i stuck thegardrn  hose in several pipes around the cooling system and water flowed through with out a problem.  

Then I connected all the hoses back up and filled the Collins system with water and started the car up.    This time I found that bottom and top radiator hoses got hot but the radiator still not warming up ,,also engine still over heats and water bubbles from expansion tank.   

 

Would a possible bad water pump cause this this problem?  Feels as the water isn’t being circulated around the system as radiator stays cold    ...  

 

would a bad head gaket cause this sort of a problem?

Edited by shakeym35

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The pump tends to weep and get noisy. It's not like the plastic impeller ones that don't flow iirc.

What happens with out the stat installed?


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59 minutes ago, duncan-uk said:

The pump tends to weep and get noisy. It's not like the plastic impeller ones that don't flow iirc.

What happens with out the stat installed?


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I’ve already removed the stat but still have over heating and cold radiator. Really odd 

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44 minutes ago, Steve van hool said:

What engine have you got? mileage? year of the car?

It’s a m30 m535i 1987 mileage 133k 

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So try bleeding the coolent, m30's are a bugger to bleed, so ensure that the coolent is circulating, if not suspect a failed water pump, and no unfortunately you cannot rule out a failed head gasket, or even a cracked cylinder head, for which the m30 engines have a reputation for.

 

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Yesterday took some time out to investigate further and discovered the heater valve to be stuck in the shut position.  That explains why there wasn’t Any hot air from heater blower.  

 

Can a seized heater valve effect bleeding the system?

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Okay thought I’d mention I’ve flushed out the heater matrix aswell all is clear and water flows well.    I’ve again flushed out all water pipe circulation all flows well.    

 

Still doesn’t explain the hot and cold radiator hoses so top gets hot and lower stays cold also radiator stays cold.... I’ve ordered a new replacement thermostat and water pump should arrive soon.     Really wanna get to the bottom of this problem.  

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Okay guys today nick and myself got the airlock out today.  Thanks Nick for making time to come over... also a big thank you to everyone who advised and suggested. Very much appreciated

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