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Discussion Starter #1
Hi everyone,

I know from searching the forum that this has been discussed at length, but I am still unclear

My daughter has a petrol 2007 M Sport 320i

Last June it started to overheat, as an interim I used Steel Seal which I had used previously with some success on other vehicles, thinking it was the head gasket

Upon starting the car with heater on full it was blowing cold, I presumed it was an air lock and upon searching this forum to find any venting points, I found the sequence for the automatic venting from the electronic water pump

At that point I found that the water pump was not working

I replaced the water pump and thermostat and the overheating stopped, but still the heater was blowing cold air

With the weather getting colder, my daughter asked if there was anything I could do

The flow and return from the heater matrix is barely warm so I am thinking a blockage due to the chemicals

I removed what I believe is one of the heater matrix pipes from the t-piece on the top hose from the radiator and attempted to flush it threw with a pressure washer, if I destroyed the matrix I would have to replace it anyway

However, something is definitely blocking the flow

My question is, does my daughter’s car definitely NOT have a valve somewhere in the circuit and the blockage is most likely to be in the heater matrix?

Many thanks for any replies
Tony
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 99K miles NOKIAN WR G3 12K miles
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Hot-water Control Valve is normally open, powered shut by IHKA. When the valve elastomer seals fail the pieces block the valve orifice effectively shutting it.
 

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3/2007 328xi E91
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...My daughter has a petrol 2007 M Sport 320i...My question is, does my daughter’s car definitely NOT have a valve somewhere in the circuit and the blockage is most likely to be in the heater matrix? Tony
Hi Tony & Welcome to the Forum!

Many E9x vehicles do NOT have a "Water Valve", but some do, depending upon model & market country. If your daughter's 320i has a "Water Valve" that acts to prevent coolant flow to the heater core in cooling mode, it would be mounted on the inboard or engine side of the Left strut housing as shown in this TIS "Installation Location."
https://www.newtis.info/tisv2/a/en/...hanical-components/y4a-water-valve/1VnbhPr7F8

TIS also has the circuit diagram for the control system for the valve to test it electrically, but you need to know which IHKA or Climate Control/ Heater system the vehicle has and the Build Month/ Year, and select the correct schematic from this page:
https://www.newtis.info/tisv2/a/en/...lectro-mechanical-components/y4a-water-valve/

Good luck,
George
 

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Discussion Starter #4
Hi Guys,

Thank you for the help, I have to say this forum has helped me enormously in the past

I probably should have said that we are in the UK, but I don’t suppose that makes any difference to the position of the valve

I am not sure of the build date, unless I can get it from the chassis number, the registration documents over here only tell you when the vehicle was first registered

I know the dash clocks were built in October 2007, because the water coming in through the passenger door panel, soaking the carpets and causing condensation damaged them, which this forum correctly diagnosed the fault and remediation

I will now have a look for the valve and report back

Thank you once again

Tony
 

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Discussion Starter #5
Hi

Just been across to the car, I don***8217;t think it has a valve, there is a space where you indicated the valve should be

I will try and find the return from the heater matrix and flush backwards

If that fails, I might try compressed air, if I damaged the matrix due to the blockage it would have to come out anyway

Tony
 

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Discussion Starter #6
So…..disconnected the flow from the t-piece on the top radiator hose, took off the hose from the radiator header tank and pressurised the whole system using bursts of water from the pressure washer

Just about to give up when water started pouring out from the flow hose to the heater materix, so looked like blockage removed

Took car for a 10 mile drive, but no noticeable heat inside the car, however the hose going to the heater matrix is now so hot that you can’t hold it, which is wasn’t before, so I think I am on the right lines, will do the same tomorrow, but for longer

Tony
 

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Kostspieliger Spaß Quandt
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The sealer you used for the overheat has clogged the narrow spiral channels for the heater core. You have no hot coolant flowing thru it to transfer heat inside the cabin. You should have disconnected and bypassed the heater core when you added the sealer.

You can try disconnecting both heater hoses and flushing the sealer out using a garden hose connected to one heater hose. Then flush the opposite way by connecting to the other hose. Then you will have to reconnect, top up with coolant and bleed thoroughly. You may still not get heat if you cannot dislodge the sediment in the core.

Edit: if in fact there was no head gasket leak you would be wise to flush the entire cooling system. The silica particles in the sealer have an abrasive property and will cause premature failure of other cooling components. It should only be used as an absolute last resort when there would be no plans to properly repair a failed HG and then only after bypassing the heater core.
 

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Discussion Starter #8
Have spent about six hours using a pressure washer alternating between the return and flow getting very little water coming out
 
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