Deleted the heater matrix

[g h j]

Hi all I've deleted the heater matrix on my e36 track car and not long after its started overheating by blowing back through the expansion tank. Might be coincidental I suppose.
I've by passed the matrix and the pipe seems to be flowing ok though it does have a piece of copper pipe at 90 degrees to make this happen, the car ticks over no problem but when driven hard it only lasts a lap before its pouring out the expansion tank
Any Idea people
TIA

[brillomaster]

In removing the heater matrix, youve removed a radiator to cool some of the hot engine coolant, and also removed some of the volume of coolant, so the remaining radiators have to work harder with less coolant than before.

Were you marginal on cooling before?

Either way, id check the system is bled properly with no air leaks, and that the water pump and thermostats are working properly. If that doesnt fix it, you might have to fit a bigger rad to bring the coolant capacity and cooling efficiency back to what they were before.

[g h j]

Thanks for the reply I have removed the thermostat but I have heard that this is detrimental would you agree ,looks like I'm going to reinstate the fittings and pipework for the heater , I meant to say I deleted the matrix rather than removed it

[brman]

you say you "passed the matrix and the pipe is flowing". Does this mean you just connected the pipe to the matrix to the return pipe? ie it is now just a loop from the engine, back to the engine? So you are getting full flow down that pipe? No heater control valve in the circuit?

Assuming I understand you, I suspect this is your problem all the water is circulating through the heater loop (with no cooling) rather than going to the radiator.

I could be wrong though, I don't know anything about that cooling system.
Alternatively, are you sure you don't have air in the system?

[chrisr29]

Sounds like an air lock or head gasket failure.

Did you bleed it via the bleed screw on the expansion tank? Is the radiator getting hot? Why did you bypass the matrix in the first place?

[paulwirral]

Put the thermostat back in , it's there to restrict the flow through the radiator as well as help the engine warm up , without one the coolant passes straight through the rad and doesn't stay in the fins long enough to actually cool down .

[g h j]

chrisr29 said:

Sounds like an air lock or head gasket failure.

Did you bleed it via the bleed screw on the expansion tank? Is the radiator getting hot? Why did you bypass the matrix in the first place?

I had a hose blow and it's was easier just to bypass it on the day ,now I gave lost the hose junction box,and yes i have bleed it a few times becoming a pain think I'm gonna have to reinstate things

[g h j]

g h j said:

I had a hose blow and it's was easier just to bypass it on the day ,now I gave lost the hose junction box,and yes i have bleed it a few times becoming a pain think I'm gonna have to reinstate things

Also I have done a compression test and all cylinders are are healthy score

[g h j]

paulwirral said:

Put the thermostat back in , it's there to restrict the flow through the radiator as well as help the engine warm up , without one the coolant passes straight through the rad and doesn't stay in the fins long enough to actually cool down .

Thanks that's interesting I will try that

[paulwirral]

g h j said:

Thanks that's interesting I will try that

It worked for me on an older Mitsubishi l200 I bought , it always ran a little hot particularly in traffic and they are notorious for head gasket or cracking heads , instead of flapping and expecting the worst I flushed the rad and went to replace the thermostat and found it missing , popped the new one in and it was fine , I used it to drive to the Dordogne numerous times after without problem .
Good luck

[g h j]

Thanks