Board logo

Aluminium Expansion Tank
shortie - 7/8/07 at 08:40 PM

I noticed tonight that the bottom of my ally expansion tank has corroded right through at the bottom and is now starting to drip water!!

It's only about 2 yrs old, has anyone else had this issue???

Rxx

UncleFista - 7/8/07 at 08:55 PM

Strange, do you use antifreeze or just water-wetter ?

shortie - 7/8/07 at 08:58 PM

Anti freeze, but it is a cooling system so antifreeze would be normal.

DIY Si - 7/8/07 at 09:43 PM

quote:
Originally posted by shortie
Anti freeze, but it is a cooling system so antifreeze would be normal.

Not necessarily on a car like this. Some use just water, maybe with water wetter. Depends how much it'll be used, as anti-freeze makes the cooling system less effective than pure water. As the name implies, it's to stop freezing, not over heating. It also includes rust inhibitors, but that's for a different reason.

[Edited on 7/8/07 by DIY Si]

caber - 7/8/07 at 10:24 PM

Ally does not like alkaline water, check the Ph of the water you get locally, if it is alkaline use distilled water or something to make it neutral like some vinegar.

Caber

bob - 7/8/07 at 10:35 PM

Yes vinegar, i had thoughts about this and decided to run with just filtered water and 50ml of vinegar, i have no idea of of what any ph reading will give me so discretion was my option.

shortie - 8/8/07 at 06:50 AM

Trouble is it's a bit late now!!

It's now I wish I should have bought some Lumiweld!!!

Rich.

02GF74 - 8/8/07 at 09:15 AM

best water to use is rain water or de-ionised water from wilkinsons (it can be other shops too if you want to pay mnore).

anti-freeze also helps lubricate the water pump - as posted last week on here.

britishtrident - 8/8/07 at 02:29 PM

Antifreeze is essential 365 days a year --- reason is it contains corrosion inhibitors. If you run an alloy minium alloy engine without corrosion inhibitors you will get problems even if the coolant is 100% pure water.

However be aware some "fleet" anififreezes such as the infamous and now defunct Holts Glycomaster contain a percentage methanol and although sold as being suitable for aluminium alloy engines they are corrosive.

Fill the system with a 30 to 50% solution of good quality antifreeze.
Modern non-methanol antifreezes come in 4 types
Old style green blue antifreezes
Japanese dark red antifreezes -- similar to above but contain silicates.
OAT long life coolants --- usually pink or orange
HOAT long life coolants

Basically don't mix them and avoid the japanese spec, although you can replace it with the green/blue stuff with a simple drain and refill.

OAT = Organic Acid Technology corrosion inhibitor.
HOAT = Hybrid Organic Acid Technology
If switching modern OAT antifreeze first flush through the whole system first with a acid based cleaner.

[Edited on 8/8/07 by britishtrident]

ChrisGamlin - 8/8/07 at 05:10 PM

Has it failed on a flat face or in a fold / join in the metal? If the latter, Id say its more likely to have fatigue cracked due to expanding and contracting when pressurised. I had an expansion tank that did that a couple of times and in the end I just replaced it rather than keep repairing it.

Not entirely related but just a word of caution with antifreeze if you have pets. Do not leave it laying around anywhere that they can drink it, even a tiny amount from a dripping hose can kill a cat / dog quite easily, as a chap on the WSCC found out a few weeks ago

shortie - 8/8/07 at 08:26 PM

Hi Chris,

It's on a flat surface mate, right in the middle of the bottom of the bottle.

Supplier has asked me to send it back for investigationreplacement.

Rich.