740 Heater blocked

  • Thread starter Thread starter noreply@invalid
  • Start date Start date
N

noreply@invalid

I have a 740 with what appears to be a blocked heater matrix.
What is the best way to clear the block, it was caused when an additive was
added to cure a leak in the rad but it appears to have also blocked the
heater.
 
noreply@invalid said:
I have a 740 with what appears to be a blocked heater matrix.
What is the best way to clear the block, it was caused when an additive was
added to cure a leak in the rad but it appears to have also blocked the
heater.
Click to expand...

Best (and possibly only) way to clear it if it's indeed blocked is to
replace it. It also could have jammed up the heater control valve. Stop-leak
additives usually cause more harm than good, they can mess up the whole
cooling system, better to fix the leak correctly.
 
noreply@invalid said:
I have a 740 with what appears to be a blocked heater matrix.
What is the best way to clear the block, it was caused when an additive
was
added to cure a leak in the rad but it appears to have also blocked the
heater.
Click to expand...
As James Sweet says, the best way is to remove and replace the heater
matrix. Sadly, that is a huge job.

You may have luck with disconecting the heater hoses (both of them) and duct
taping a garden hose to the outlet pipe (the upper one, I think) of the
heater matrix. Open the tap a bit and try to flush the heater backward that
way. If dirty water starts coming out you can increase the flow - ultimately
you should be able to get water through it like you'd get out of a kitchen
tap. If it resists, try it on the other pipe - and keep pushing back and
forth until you give up or you get a good flow of clear water.

If the heater still doesn't work, don't forget there is a heater control
valve near the matrix in the lower hose. Those valves get grungy and jam.

Mike
 
Thanks, the hosepipe did the trick
Michael Pardee said:
As James Sweet says, the best way is to remove and replace the heater
matrix. Sadly, that is a huge job.

You may have luck with disconecting the heater hoses (both of them) and duct
taping a garden hose to the outlet pipe (the upper one, I think) of the
heater matrix. Open the tap a bit and try to flush the heater backward that
way. If dirty water starts coming out you can increase the flow - ultimately
you should be able to get water through it like you'd get out of a kitchen
tap. If it resists, try it on the other pipe - and keep pushing back and
forth until you give up or you get a good flow of clear water.

If the heater still doesn't work, don't forget there is a heater control
valve near the matrix in the lower hose. Those valves get grungy and jam.

Mike
Click to expand...
 
You were lucky! I had to replace the entire unit. WHAT a job! The
steering wheel and pedals were left. But I managed to fix dodgy wiring, get
all dash lights to work, and a few squeaks as well. But never again I hope!
Paul
 
Reverse flush using a hose or low setting on a pressure washer with pulse
jet nozzle. You may need to remove the matrix to make sure you don't need to
swim in your seat.

Cheers, Peter.
 
You must log in or register to reply here.
Back
Top