I decided to give the engine a run on the weekend and checked the water level first. I added about 3 litres . Also noticed there was a brown scum sitting on top of the fins. As I had no steering wheel attached to drive it, I let it idle for about 10 minutes and tightened a small leak at the bottom hose/radiator join - hopefully that was the cause of the loss and I’ll keep an eye on it.
I reckon I need to do some flushing and cleaning of the system - any recommendations on the best way to do it, including which flushing product and which coolant to use in the mighty grey?
The best way is to pull the motor out of the car, rip the head off, remove the welch plugs, and go nuts with a Gerni in the water passages. Then buy a 7424869 head gasket from Harv, rework the holes behind No. 6 cylinder as per fitting instructions and bolt everything back together. While you're doing the engine work, take the radiator off to a place which still does proper radiator servicing, and get them to pull the top and bottom tanks off and clean the tubes out.
[\facetiousness]
I've had some success with oxalic acid. Dissolve say two cupfuls in a couple of litres of hot water and add to your cooling system. You can let it stay in there for a week or so, then drain the contents of the cooling system and flush with clean water. Repeat as often as needed.
Warning: Oxalic acid's poisonous, and is a powerful bleach. Wear old clothes.
You can clean your radiator out with some oxalic acid solution and the barbecue. Put the cap on the radiator, put it on the barby and fill with oxalic acid solution until the tubes are just full. Put the top and bottom hoses on. Fire up the barby on low just until you can hear the solution boil. Pick the radiator up by the hoses and gently rock back and forth a few times (leather gloves!). Heed warning above. Pour the hot, and now sickly green-brown solution out into a bucket, and flush the loosened scale out of the radiator. You'll be surprised how much scale comes out. That'll be maybe a third of what's in there. Then take the radiator off and get it professionally serviced.
There are two schools of thought about coolants/additives. One is to use the green glycol-based coolant. I subscribe to this one. The other school of thought says never use coolants, only fresh water and water-soluble oil.
Thanks heaps, Rob. I may try the “facetiousness” method when I put the original motor back in. I bought one of Harv’s gaskets when he did the run, even though I wasn’t running a grey at the time.....must have known something
I’ll see if I can find some oxalic acid in the meantime.
. Also noticed there was a brown scum sitting on top of the fins. As I had no steering wheel attached to drive it, I let it idle for about 10 minutes and tightened a small leak at the bottom hose/radiator join - hopefully that was the cause of the loss and I’ll keep an eye on it.
