Coolant and heating issues

nd-photo.nl

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Mar 6, 2012
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My cap was weak when I tested it, when I was fault finding ultimayle having matrix issues - it leaked at around 10-12psi from memory vs the rated 24psi.


This blue circle is the overflow - If the system over pressurises and the cap vents, any coolant should vent out this spout. I would see a puddle of coolant on the metal work below this spout.

View attachment 50811
This was exactly why I thought of the coolant cap :cheers:
 
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Compo1

Active Member
Jul 19, 2010
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this is kind of where i go with it. i think i will do the full drain and flush, change the cam belt and pump and do the egr cooler at the same time.

i checked the pipes as you said and one gets warm quickly and the other warmer slowly.. its a hard one to test as 3 of the 4 heaters on the front are nice and warm. its just that far one! i believe its relatively easy to get at so might park this one for now and see if the flush does anything for now.

its the cooler thats the costly part as the other items dont help with exhaust gasses in the system. apparently the egr coolers on this model are quite common!
The Charge cooler is also a common problem on these.

If this was my car as the one martix pipe is only getting warm slowly I'd go about it like this, although id be doing it myself.

Power flush the whole system disconnecting pipes as i went as described earlier.

Heater Matrix swapped out.

Bypass the charge cooler, really easy to do to rule that out. Or Bore scope

And only then would a look towards the EGR cooler. It could well be that but thats an expensive job unlike diagnosing the charge cooler. Any garage should have a bore scope to look for water in there.
 

OVB

Oct 3, 2025
9
2
The Charge cooler is also a common problem on these.

If this was my car as the one martix pipe is only getting warm slowly I'd go about it like this, although id be doing it myself.

Power flush the whole system disconnecting pipes as i went as described earlier.

Heater Matrix swapped out.

Bypass the charge cooler, really easy to do to rule that out. Or Bore scope

And only then would a look towards the EGR cooler. It could well be that but thats an expensive job unlike diagnosing the charge cooler. Any garage should have a bore scope to look for water in there.
Yes I agree it's not the cheapest one to do however the issue still remains the exhaust gasses. From my understanding the charger will never mix to cause gasses in the coolant. The only 2 that can do this is the head gasket and EGR cooler from my understanding?