Please - how do you clear the sludge of mixed antifreeze?
Discussion
Please - how do you clear the sludge, of mixed antifreeze types, out of the radiator and heater matrix ?
I've just recently bought an old jag, and noted the antifreeze was a very light pink colour (HOAT) whereas on this age of car it should be blue (IAT), However it was clear of brown sludge. And so, I drained the pink out (removing the bottom hose) and flushed the radiator out with the garden hose. In doing so., I noted unusual (to me) mix of bits in the catch tray .. pink, blue and dark coloured particles (the latter of which were probably rust from the old cast-iron block). I took a photo which I'll try to upload . . .
When refilling the radiator (with 50:50 blue antifreeze) I noted that it was annoyingly slow filling. I've also have issues with the heater not working, and so I bled that by removing its top hose. I noted the heater matrix (as I pumped water through) was already full of coolant, with a blue tinge to it. But even after bleeding and restarting the engine - hot water doesn't flow through it (its pipes remain cold).
I been led to understand the issue to be ; the car's original antifreeze was blue IAT, and sometime before I got the car its been refilled or topped up with pink HOAT, which is not compatible. Reading other posts on this forum - contributors suggest that the mix of these two chemicals creates a sludge. 1 + 1 = 3 .. corresponds to the coloured particles in the catch tray, and more importantly the very slow refilling of the radiator core ..and the lack of flow through the heater matrix.
There was also pink crystalline particles around the thermostat gasket. . .
I've also noted the thermostat's gasket face is corroded away. . .Being the new owner-mechanic I don't know whether that corrosion is related, but the gasket face now needs redressing smooth and flat.
And again, although possibly unrelated.. the water pump bearings are on their way out. A NOS pump is on its way.
Furthermore, I don't know if the situation has been aggravated by the wrong thermostat being fitted (it should have been of the sleeved type, to close off the bypass hose). As a consequence there's been lesser flow was through the radiator itself (..the bottom of the radiator was cold, when the top and the thermostat were at 83 degrees). I've now sorted the by-pass issue / lack of thermostat sleeve.. by fitting a restrictor disc in the bypass hose. I'm told this is not unusual practice.
The car had only driven (..according to MoT records) just 310 miles over the past ten years. I have been recommissioning her since mid January, and last month drove 380 miles. Normally, the temperature stays at 83 degrees (when the thermostat opens) but soon rose to 95 degrees when stopped slow crawling n traffic for ten minutes.
So to reiterate - Please - how do you clear the sludge, of mixed antifreeze types, out of the radiator and heater matrix ? I can flush again, I can back-flush, and even remove the radiator to shake it all about, but is there a chemical cleaner that will help dissolve the sludge blockages ?
One contributor to this forum suggests Fernox F8, domestic central heating cleaner .. "a super strength, fast-acting cleaner for heavily contaminated, dirty and problem central heating systems. Its citrate-based, pH neutral formulation removes debris, sludge and scale without the need to neutralise. "
As my car's radiator is a brass one, with soldered joints, and the engine's cylinder head and catch tank are both aluminium, I'm naturally keen not to dissolve these parts and end up with more of a problem than I already have.
Your experience / advice would be much appreciated - Thank you
Pete
I've just recently bought an old jag, and noted the antifreeze was a very light pink colour (HOAT) whereas on this age of car it should be blue (IAT), However it was clear of brown sludge. And so, I drained the pink out (removing the bottom hose) and flushed the radiator out with the garden hose. In doing so., I noted unusual (to me) mix of bits in the catch tray .. pink, blue and dark coloured particles (the latter of which were probably rust from the old cast-iron block). I took a photo which I'll try to upload . . .
When refilling the radiator (with 50:50 blue antifreeze) I noted that it was annoyingly slow filling. I've also have issues with the heater not working, and so I bled that by removing its top hose. I noted the heater matrix (as I pumped water through) was already full of coolant, with a blue tinge to it. But even after bleeding and restarting the engine - hot water doesn't flow through it (its pipes remain cold).
I been led to understand the issue to be ; the car's original antifreeze was blue IAT, and sometime before I got the car its been refilled or topped up with pink HOAT, which is not compatible. Reading other posts on this forum - contributors suggest that the mix of these two chemicals creates a sludge. 1 + 1 = 3 .. corresponds to the coloured particles in the catch tray, and more importantly the very slow refilling of the radiator core ..and the lack of flow through the heater matrix.
There was also pink crystalline particles around the thermostat gasket. . .
I've also noted the thermostat's gasket face is corroded away. . .Being the new owner-mechanic I don't know whether that corrosion is related, but the gasket face now needs redressing smooth and flat.
And again, although possibly unrelated.. the water pump bearings are on their way out. A NOS pump is on its way.
Furthermore, I don't know if the situation has been aggravated by the wrong thermostat being fitted (it should have been of the sleeved type, to close off the bypass hose). As a consequence there's been lesser flow was through the radiator itself (..the bottom of the radiator was cold, when the top and the thermostat were at 83 degrees). I've now sorted the by-pass issue / lack of thermostat sleeve.. by fitting a restrictor disc in the bypass hose. I'm told this is not unusual practice.
The car had only driven (..according to MoT records) just 310 miles over the past ten years. I have been recommissioning her since mid January, and last month drove 380 miles. Normally, the temperature stays at 83 degrees (when the thermostat opens) but soon rose to 95 degrees when stopped slow crawling n traffic for ten minutes.
So to reiterate - Please - how do you clear the sludge, of mixed antifreeze types, out of the radiator and heater matrix ? I can flush again, I can back-flush, and even remove the radiator to shake it all about, but is there a chemical cleaner that will help dissolve the sludge blockages ?
One contributor to this forum suggests Fernox F8, domestic central heating cleaner .. "a super strength, fast-acting cleaner for heavily contaminated, dirty and problem central heating systems. Its citrate-based, pH neutral formulation removes debris, sludge and scale without the need to neutralise. "
As my car's radiator is a brass one, with soldered joints, and the engine's cylinder head and catch tank are both aluminium, I'm naturally keen not to dissolve these parts and end up with more of a problem than I already have.
Your experience / advice would be much appreciated - Thank you
Pete
Oh dear. We were warned not to mix those when the Pink stuff came out. For what its worth, the pink stuff is a significant upgrade over the old blue, its got quite good anti-corrosion properties. I'm not aware of any chemicals that are better or worse for fixing this, what is would say, is that its not the radiator and heater matrix we were warned about blocking, it was the water galleries in the cylinder head and block.
Before introducing any chemicals/potions, it is worthwhile trying the flush/backflush technique. It's worked every time for me bar once (when I had to replace a heater matrix on a 106 diesel) when dealing with a silted up cooling system, most recently on a Toyota Starlet which again had the anti-freeze types incorrectly mixed.
Sounds like a blockage in either the radiator or the heater matrix. It could also be a blocked hose if there's a small diameter one somewhere in the cooling system.
Run the engine up to temp so the thermostat is open and feel around for a cold hose.
Hot hose going into the radiator cold coming out means blocked radiator. Same thing goes for the heater matrix.
You can use a pressure washer down the disconnected hoses to try and free the blockage but don't go mad with it do it in small bursts or you could blow the radiator.
All hoses and radiators cool then possible water pump if it has plastic impellers that have broken off, fairly common with that design of pump.
Run the engine up to temp so the thermostat is open and feel around for a cold hose.
Hot hose going into the radiator cold coming out means blocked radiator. Same thing goes for the heater matrix.
You can use a pressure washer down the disconnected hoses to try and free the blockage but don't go mad with it do it in small bursts or you could blow the radiator.
All hoses and radiators cool then possible water pump if it has plastic impellers that have broken off, fairly common with that design of pump.
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