Dead antifreeze

[Bat21]

I have just read that antifreeze can become ‘dead’ and lose it’s ability to prevent the engine from freezing, preventing corrosion and, more importantly to me, lose it’s ability to keep the engine cool.

My 80 has used no coolant since I rebuilt the motor 7 years ago now, so obviously it has the same Toyota Red coolant in there.

On this years Morocco trip I did see engine temps rise up to around the 100c mark, it normally sits at 80. Could it be the coolant has lost its ability keep the engine cool.

Does anyone else change their coolant, does anyone know if this is done at a recommended interval?

 

[frank rabbets]

Depends who you read. Too much info on the net. Ethylene glycol is chemically stable so that should last indefinitely but the additives my deteriorate. What is a certain though is to get the right anti freeze for the car as some water pumps require certain additives. I went to Halfords to get mine and they talked me through which one needed.

 

[Towpack]

Water based coolants (ethylene glycol etc) certainly do not last indefinitely. Corrosion prevention, freezing and boiling points will all deteriorate over time. I use the Halfords OAT red stuff which offers a 5 year life. Waterless coolants like the Evans Coolant claim a 20yr life and superior protection all round but it's not cheap, especially as you have to flush out the system with a prep fluid first to get all traces of water out.

 

[Michael Montgomery]

Changed mine recently to better red toyota antifreeze. Told this is a ten year factory certification. Is your fluid levels ok?

 

[Bat21]

Thanks for the replies folks.

As it is now 7 years old I think I may just drop it out and replace with new, just for peace of mind.

Yes Dervis levels are spot on.

 

[Michael Montgomery]

No harm in changing after 7 years that’s pretty good going. I’ve changed mine 3 times in that time for various reasons.

 

[Dave2000]

I change mine circa two to three years. The only reason is I have found that sludge/rust/calcium or whatever collects in the lower L/H (opposite to bottom hose), area of the radiator, so I am guessing flow here is very weak, this allows the deposits to accumulate.

Eventually these deposits will build up and eventually become large enough to be swept up and circulate around the cooling system.

So for me it is more about preventative maintenance but, it does indicate that the corrosion inhibitors effectiveness falls off within a short time.

I find modern engine cooling systems tend to stay cleaner for longer, the streamlining of build materials, cleaner production techniques and modern antifreeze working hand in hand.

Here in Spain antifreeze comes ready mixed, just choose your colour, and then whatever temperature you want to protect down to. I think your coolant/antifreeze life will also be affected by whether you mix or top up with tap water or distilled, or perhaps mixing brands?

Regards

Dave

 

[chapel gate]

Blue is two years, red five according to the manufacturers.

I use the deionised water.

My unimog manual states to use tap water. Dont know if its a all cast iron engine or not yet, if this makes any difference...

 

[Shayne]

The way i look at it is inhibitors slow the corrosion but don't prevent it so even if coolant is still good from a chemical point of view the cooling system should be flushed every 3 years or so on car as old as ours just to prevent a build up of anything that might be deteriorating internally .

 

[Grimbo]

Ready mixed at 50/50 is probably the way to go , tap water even in a Mog is not good practice really .
You may have no problems if you live in a soft water area but look inside your kettle and you will still see lime scale , live in a hard water area and you probably need a new kettle every couple of years.....the same thing will be happening in your engine although the anti freeze will have an additive package to try and help .
Beware of mixing OAT and normal coolants although most engines are backwards compliant with OAT if you flush the system well first......the Toyota red Forlife coolant was and is probably the best option although I run mine on JCB ready mixed coolant and change every 3 years or so.....mainly because I had an unlimited supply of the JCB stuff but it's good and cheap if bought from a JCB dealer in 20l cans compared to buying smaller amounts from a motor factors......just to add I don't work for either JCB or a dealer ;-)

 

[StarCruiser]

The way I see it is that for any metal to oxidise (corrode) it needs free oxygen and whatever is circulating around as coolant contains an amount of it. Once this is used up, by corrosion, the corrosion should stop unless more oxygen is introduced. Thus removing and replacing coolant only gives added fuel to the corrosion process.

For example, an unpressurised domestic heating system is designed to fill from and expand into the header tank. The connection point of this tank and expansion pipe are critical to avoid 'pumping over' where water pumps into the header tank and circulates back into the system, pulling oxygen in with it. With such a wrongly functioning system, the steel radiators do not last long before springing leaks.

 

[frank rabbets]

Halfords Red OAT free is recommended for the 80 engine. Life is so complicated these days. You need a laptop now to bleed the brakes on some Mercs.

 

[Towpack]

. You need a laptop now to bleed the brakes on some Mercs.

Eh? So that's progress?

 

[Dave2000]

TD5 Discovery needs a laptop to bleed the brakes, and that is around 20 years old now. The technology is racing ahead of us, even within the trade we struggle to keep up.

Years ago, depending on how much pocket money I had, it was either el cheapo no brand antifreeze or, if I had washed a few extra cars and was feeling a bit spendy then my Zephyr got Bluecol.

Toyota want you to use their red, Ford want pink, GM orange and so forth, each claiming their version is 'special' and particular to their individual products. I do not believe for one minute that the 'Toyota Red' of today has the same chemical make up that it had when Mr T was recommending it for the Land Cruiser 80 thirty years ago.

It is about time to introduce a universal type antifreeze............again or, with our older engjnes, choose your flavour, change and flush at a maximum of three years and sleep well on those (cold) nights.

Regards

Dave

 

[frank rabbets]

I still get that corrosion on the ally top tube on the 80 Dave so nothing much has improved since the 50's.

 

[Dave2000]

Frank, are you talking about under the rubber hose where it meets the alloy and where you clamp with the jubilee clip?

Strange that, I get very little around the top tube outlet but nothing on the bottom inlet, temperature related?

Regards

Dave

 

[Dave2000]

Blue is two years, red five according to the manufacturers.

I use the deionised water.

My unimog manual states to use tap water. Dont know if its a all cast iron engine or not yet, if this makes any difference...

Hmmm....Unimog.

Regards

Dave

 

[Towpack]

I seem to remember that some budget antifreeze years ago used methanol instead of EG.

I get no visible corrosion at all with the Halfords OAT stuff.

 

[Dave2000]

I seem to remember that some budget antifreeze years ago used methanol instead of EG.

I get no visible corrosion at all with the Halfords OAT stuff.

IIRC you may be correct TP. I do remember my father mentioning changing antifreeze, and something to do with fires?

Regards

Dave

 

[t1pper]

IIRC aside from visually checking what your coolant looks like and the standard hydrometer test antifreeze can be tested with a multimeter a small voltage can be detected by through the coolant and the ground of the vehicle.
A voltage can lead to electrolysis and speed up corrosion of the internals .
Several you tube videos cover the process in more detail.
If it passes all 3 tests it should be safe to leave in the car.