740 Heater Matrix

1988 740.

I can hear the water in the matrix gurgling as I drive along.
The gurgling last only a few seconds and happens about every 20 seconds or
so.
Any ideas what happening with it.

 

Air or vapour in the cooling circuit, probably caused by low coolant level
or headgasket failure, undo the coolant filler cap after a running the
engine for a little while (be carefull, there might be pressure in there)
smell inside the reservoir, If it smells exhausty, or petrolly, then the
headgasket has breached, otherwise check the inside of the oil filler cap,
the presence of quantities of white gunk indicate possible head gasket
breach, otherwise you have a normal coolant leak somewhere, the rad cap
isn't sealing properly, or it just hasn't been topped up or checked for
ages.

Top up the coolant now!!! If the coolant is low enough for vapour/air to be
being pumped through the heater matrix, then the level is critically low,
and you are risking overheating your engine.

Ken Phillips

 

Ken
I have run all the checks you said and they are all O.K.
The radiator is at max so I am not losing any water.
The only other thing I can think is thee is some for of partial block in the
matrix restricting the flow.
I now notice that the gurgling is only if I reve the engine up.

 

I used to swap the hoses around after flushing the system on my Fords
..Reverse flushing sure helps sounds like the gunk is slowing down the flow
of liquid .