Alloy Radiators

[Bender]

Is it common for alloy radiator to use abit of water?

I have 40mm one in my Legnum and after long trips I always had to top the radiator with around 1 litre of water, Around town it fine but it just after driving the car 3-4 hours it need abit of water, It doesn't leak water and it had new antifreeze put in about year ago/15,000kms ago.


But what is this stuff sitting on the radiator cup? Also in the radiator and in the over flow bottle

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[CANDEE]

An alloy radiator shouldnt use any water at all, I know yours is a Scarles one but i think the only issues with them was fitment.

I have a Golpher(which the scarles ones are copied off), and have no water usage issues.

[elnevio]

That looks like the residue you get when glycol (blue/green) coolant has been mixed with the longlife pink OAT stuff. What coolant is/has been in there?

[Bender]

That looks like the residue you get when glycol (blue/green) coolant has been mixed with the longlife pink OAT stuff. What coolant is/has been in there?

When we done the coolant I know it was green antifreeze we put in but I wouldn't have clue what been used in the past, I have only own the car for 13 months

[Bender]

We thought it was losing pressure but radiator cap was replace back in March cause of that issue.

We thought maybe getting so hot that the water could be vaporizing? The temp gauge has always sit just under half way.

[wintertidenz]

Check if there's a split hose somewhere - even a pinhole leak will cause issues.

Also flush and rebleed the system. That corrosion points to either the wrong coolant, or not enough coolant mix.

[Bender]

Ready had a look for leaks but can't see any and doesn't dip any water under the car

Probably is down coolant due only refilling with water.

[wintertidenz]

IIRC you also have to get the right coolant ratio with an alloy radiator. It's safer to aim for 33% and get 40% than go over 50% or under 33%.

[crazydriver81]

what is that brown crap? Can you wipe it off or is it like real rust? I'd say that this stuff makes the rad-cap not sealing properly and the system pressure cannot be build up completely, which makes the coolant boiling and going to the overflow tank.

Next stop will be a PROPER bleed of the coolant system to evacuate ALL air. Again, air in the system avoids the full pressure to be build up and makes the coolant boiling easier.

So, flush all that crap out (hopefully you are able to get all that brown stuff out). I personally would bleed the coolant system, remove thermostat. refill with water and coolant flush. Afterwards another 3-4 fills with pure water, to flush all residues out. Install thermostat, refill with proper (green) coolant and bleed the system.

[Bender]

Can wipe the brown crap away and I have. The radiator cap was replace about 6 months ago and that the same time we pressure test the system as the old radiator cap wasn't sealing as it was pushing the cooler to overflow and back and coolant was boiling at times.

The thermostat was replace when we done change the coolant a year ago so the thermostat should be fine and the whole system at the time was bleed properly. I'm sure that brown crap stuff was in the radiator was in it at the time when I bought it. Do remember fulling the radiator with few litres of water when I first got it home is to why the coolant was change.

But like I said, It only seems to be after long drive it will lose abit of the coolant, Doing around 250 + kms a week and can go weeks with out topping up the coolant but as soon been for 3 + hour drive, coolant needs to be top up.

I will flush the system this week and see if we can get brown crap out and refull with coolant and see how it goes. It due to have the cambelt, waterpump ect done in the next 2000kms

[crazydriver81]

Can wipe the brown crap away and I have. The radiator cap was replace about 6 months ago and that the same time we pressure test the system as the old radiator cap wasn't sealing as it was pushing the cooler to overflow and back and coolant was boiling at times.

The thermostat was replace when we done change the coolant a year ago so the thermostat should be fine and the whole system at the time was bleed properly. I'm sure that brown crap stuff was in the radiator was in it at the time when I bought it. Do remember fulling the radiator with few litres of water when I first got it home is to why the coolant was change.

But like I said, It only seems to be after long drive it will lose abit of the coolant, Doing around 250 + kms a week and can go weeks with out topping up the coolant but as soon been for 3 + hour drive, coolant needs to be top up.

I will flush the system this week and see if we can get brown crap out and refull with coolant and see how it goes. It due to have the cambelt, waterpump ect done in the next 2000kms

Sounds like a good plan. But why flushing and refill now, when waterpump needs to be done in 2k kms? I'd rather do it at that occassion. ;)

[Bender]

Sounds like a good plan. But why flushing and refill now, when waterpump needs to be done in 2k kms? I'd rather do it at that occassion. ;)

It what I had plan to do and probably will do(save me doing twice I guess) It only going be few months away from doing it, Getting very close to 200,000kms..

[CANDEE]

IIRC you also have to get the right coolant ratio with an alloy radiator. It's safer to aim for 33% and get 40% than go over 50% or under 33%.
As Dan says you need to have a 50% ratio, as 33% becomes acidic and will eat the alloy.

[crazydriver81]

An alloy radiator shouldnt use any water at all, I know yours is a Scarles one but i think the only issues with them was fitment.

I have a Golpher(which the scarles ones are copied off), and have no water usage issues.

Out of interest, where did you got the alloy rad from and will the 40mm thick core work with stock fans? Any clearance problems? Thanks and sorry for /Hijack

[crazydriver81]

As Dan says you need to have a 50% ratio, as 33% becomes acidic and will eat the alloy.

50 / 50 means then 50% coolant (green) and 50% water I guess? Or will it be better to switch to the red coolant instead? I am a n00b so, sorry for that stupid question. :)

[Davezj]

if the rad cap has that much brown sludge on it you can bet the radiator care has started to block up.
i would take the radiator off completely and do a flow test on it to see if it is blocked to any extent then look at running some kind of flush agent through the radiator until it is sludge free. re fit the rad use a flush in the rest of the cooling system. re move rad again and re check it and re clean it if necessary.
i personally would be worried by that amout of sludge in my cooling system. i would be wanting to flush the complete system and checking the thermostat as well, not to mention probably replacing all the small bore water pipes in the engine bay and check the flow on the heater matrix as well.

sorry to be the one that says it but look bad. are you sure it is not oil/coolant mix?
or is it definitely mis match of coolants.

[swinks]

As Dan says you need to have a 50% ratio, as 33% becomes acidic and will eat the alloy.
Ran 35% ish ratio for 4 years now and never had problem with rad corrosion.
Most glycol based antifreeze have anti-corrosion additive.

BTW, sludge builds up not due to corrosion of aluminium (radiator or engine heads) but due to corrosion of cast iron engine block passages.
After swap engine for one which was sitting for almost 2 years, I had to fulsh full system from sludge 5 times to get good results and clean coolant.

Faulty water pump maybe culprit for building up sludge preventing right circulation of coolant in engine block, also it may be where coolant gets missing :)

[CANDEE]

Out of interest, where did you got the alloy rad from and will the 40mm thick core work with stock fans? Any clearance problems? Thanks and sorry for /Hijack
Mine is a Golpher from Aus, but seems they have gone out of business.

I did use the factory fans, but needed to massage the rad fan shroud a bit as they are pushed way back. I just pulled them out and went with slimlines.

And yes a 50/50 mix is the 50% Glycol antifreeze and 50% water.

[crazydriver81]

Thanks CANDEE

Golpher rads are still available... http://golpher.net/e/ptxwebstore_product/product_detail.asp?sku=314