Radiator - time to renew / refurb ?

[Bob Meadows]

Central heating descaler is ideal for car radiator/blocks:~

Mixed metals isn't a problem and it goes a long way with far better performance than radiator brands.
Leave it in the system for as long as possible- keep bringing up to temperature & flush out when ready.
Bob.

[Laird Scooby]

Originally Posted by Bob Meadows

Central heating descaler is ideal for car radiator/blocks:~

Mixed metals isn't a problem and it goes a long way with far better performance than radiator brands.
Leave it in the system for as long as possible- keep bringing up to temperature & flush out when ready.
Bob.

Correct me if i'm wrong Bob, aren't most central heating descalers caustic soda based? It's an excellent flushing agent but can eat solder! I used it once on an L24E Datsun engine and the rad sprung a few leaks. Strangely they sorted themselves after flushing with clean water.........

[c1800]

Dave’s description of flushing is good, I would add this to the flushing procedure. Remove the draincock from the block (just to the rear of the oil filter) and with you garden hose in the thermostat opening flush through the block. I also back flushed through the draincock opening with the garden hose till the block filled with water and then let it drain out from there. ( do this several times). You might be surprised what that stirred up and came out when draining.

As to the thermostat , you’d be better off with one having the pintle valve, as it facilitates relieving any airlock in the system when refilling and topping up.

[Bob Meadows]

Never had a problem with central heating descaler- household copper pipe is full of soldered joints without any issues:~

I've used it on the Volvo 240 and on the Riley for years- this car has mixed metals and a copper/brass radiator with solder joints and its been fine, in fact the Riley RM club generated the product for flushing many years back so a lot of cars have used the same.
The heater in these is quite small with very small water passages all soldered together- no floods have been reported! only that the water came out like tomato soup!
Hope it helps.
Bob.

[142 Guy]

Vinegar was mentioned as a cleaning solution. If you get the cleaning vinegar (10% acetic acid) it will be more effective than household vinegar. Both will be relatively slow. For a little faster action, Permatex makes a heavy duty radiator cleaner which is based upon hydrochloric acid.

https://www.permatex.com/products/cl...ner/?locale=en

Muriatic acid is a somewhat diluted form of hydrochloric acid and is usually available from hardware stores, probably for a lot less than the cost of the Permatex cleaner.

Acid based cleaners will be effective at removing rust and scale (carbonate and mineral deposits). Rust should not be an issue in your vintage radiator. Acid based cleaners will attack aluminum so it is not to be used with an aluminum radiator. The pump housing and radiator housing on the B18/20 are pot metal / aluminum so continuous exposure to strong acidic solution will result in corrosion. Some pumps have a cast impeller and I don't know whether the impeller is cast aluminum (a problem) or cast iron. If you want to do a protracted clean of the radiator, removing the radiator and filling it up with the acid solution to allow cleaning may be the better choice to avoid the risk of damage to the aluminum parts on the engine. Be sure to flush with water to remove any residual acid before refilling.

Sludge in the tubes is a different problem than scale build up. I do not know how effective acids are at dealing with whatever sludge is made up of. Sludge may require a more aggressive treatment with caustic compounds; but, after aggressive caustic cleaning you would want to have the radiator pressure tested to check for damage from the cleaning solution.

I can't remember whether it was mentioned; but, if you are not using a pre mix coolant be sure to mix with distilled or demineralized water. No point in adding minerals back in after you just cleaned them out.

As for bent fins on the radiator, fin combs are fairly inexpensive and can do a fairly good job of restoring the fins to almost new condition.

[Laird Scooby]

Originally Posted by c1800

Dave’s description of flushing is good, I would add this to the flushing procedure. Remove the draincock from the block (just to the rear of the oil filter) and with you garden hose in the thermostat opening flush through the block. I also back flushed through the draincock opening with the garden hose till the block filled with water and then let it drain out from there. ( do this several times). You might be surprised what that stirred up and came out when draining.

As to the thermostat , you’d be better off with one having the pintle valve, as it facilitates relieving any airlock in the system when refilling and topping up.

In an ideal world, i'd wholeheartedly agree with everything you've said there except for one thing - removing the 'stat and refitting the housing and top hose means you can get a solid, leak-free (near enough) connection to the hose so none of the flushing water "falls out" of the 'stat housing.

However it's not an ideal world and i've heard so many horror stories over the years about draincoks shearing i wouldn't advise going anywhere near them. Also using my method of backflushing ensures you get almost everywhere in the system, negating the need to remove the draincock and therefore the risk of it shearing.

Most if not all thermostats are sold with a jiggle/pintle valve here, a useful point to note is if the 'stat sits on a vertical plane, the jiggle valve should be uppermost, if horizontal then nearest the lowest point of the housing/hose that fits on top of the 'stat to promote self-bleeding.
Also my method of burping the system by squeezing the bottom hose during the topping up of firstly antifreeze and secondly water helps to minimise any air locks in the first place.
Parking uphill during the overnight cool-down further assists the removal of air.

Originally Posted by Bob Meadows

Never had a problem with central heating descaler- household copper pipe is full of soldered joints without any issues:~

I've used it on the Volvo 240 and on the Riley for years- this car has mixed metals and a copper/brass radiator with solder joints and its been fine, in fact the Riley RM club generated the product for flushing many years back so a lot of cars have used the same.
The heater in these is quite small with very small water passages all soldered together- no floods have been reported! only that the water came out like tomato soup!
Hope it helps.
Bob.

Sorry Bob, i should have been clearer, i left the caustic soda in my Datsun for far too long! Had i flushed it out almost immediately after using, i would have been alright. However i had a breakdown i had to go out on and that was the first of many that week, plus my normal hours of work so i didn't actually get the chance to do anything about it until about a week later!