after searching the net for"toyota coolant"i found many sites for other toyota import owners[mr2,hi lux surf,supras etc].on many of these sites theimportance of only using toyota forlife coolant due to these other toyota models suffering from head gasket failure.on one site it was stressed that you should never use water and anti freeze in a toyota.i know i have harped on about this before,but with so many other people stressing the importance of using toyota's own coolant,maybe there is some substance to it and maybe there could be a way of investigating further.if anyone else would like to run a web search "toyota coolant"they too would see that the evidence is quite compelling and needs looking into.

- (#8277) jeremy everingham, 29 Apr 03 4:22

Hello Jeremy, please don’t think I’m being condescending, but it may be of interest if we start with the very basics.

Obviously some form of coolant is needed to stop the engine overheating. Water is the obvious choice because its readily available and cheep to use. The bad news is that its freezing point is to high, and its boiling point is to low. In order to improve this, chemicals are added. More bad news I’m afraid, once you have added these chemicals to a conductive fluid, the different metals used in the cooling system start to react with each other. Aluminium is usually the most affected metal, and is dissolved away. To prevent this, more chemicals are added to neutralise the conductivity, and the acidity of the coolant.

An important note here is that after a period of time, some of the chemicals start to breakdown and cause the coolant to become acidic. This is why you should always replace your water based coolant every two years.

The mixture of chemicals that are needed, depends on the amount of each different metal in the cooling system. As every make of car has a different composition of metals, every make of car will require a different composition of coolant. This is why car manufacturers will have their own highly recommended coolant. Use the wrong one, and the coolant you thought was protecting your engine, may well end up damaging it.

Now ask your self this question. How important is it to use the recommended fluid in a car that’s over ten years old, with little or no service history? If any component has been replaced, the original composition is likely to have changed, therefore the recommended coolant may not have the right balance of chemicals. Its a personal choice. Go with what ever you feel comfortable with.

Regards
dave Bright

- (#8278) dave Bright, 29 Apr 03 9:30

my radiator has started leaking again, so have decided to bite the bullet and get a recore in a couple of weeks.
i'm going to take the oppurtunity to flush/ clean coolant system. what am i best using for the summer when i refill, to get best heat transfer, water/antifreeze, or just water?
thanks.
btw, dave mason, if you get to see this, any chance of wiring diagram for audible temp alarm, (or am i being cheeky??)?

- (#9228) eddie arrowsmith, 19 Jun 03 16:47

Hi Eddie

The best water based coolant to use is the Toyota red stuff. This is because it has been formulated to fully protect the Toyota cooling system, not just from freezing, but from corrosion, and electrolysis. There are other cheaper coolants, but they won’t have the exact same properties as the Toyota coolant. However, as you are renewing the radiator core, this will change the metallurgy of the cooling system, so even the Toyota coolant will no longer have exactly the right properties. So it’s a personal choice, but anything is better than nothing. I am trialling waterless coolant in my Townace at the moment and its working great, apart from a minor hick up that time permitting, I will resolve.

The best mix is 50/50 because its the easiest. Buy a 5-litre bottle of coolant, and a plastic measuring jug. Add 2.5 litres of coolant to your system, then add 2.5 litres of water. Obviously this gives you a 50/50 mix in the cooling system. Then fill the coolant bottle up with water, this also results in a 50/50 mix. Add as much as you can to the system. What remains in the bottle is still 50/50 so that if you have to top up the system, you will maintain the same 50/50 mixture.

When filling, do it slowly. If you use a hose shoved in the filler neck, it will cause aeration of the water. This air will be released as the coolant heats up, and will cause many air locks, so “slow” is the key when re-filling the cooling system. If you can, use distilled water, as this has no air or impurities.

Once you have changed the coolant, keep an eye on the level in the expansion tank.

Regards
dave Bright

- (#9229) dave Bright, 20 Jun 03 1:26

Hi Guys
I'm having to top the coolant up every day (about 2 pints ) Have noticed when running the engine cold with the radiator cap off, coolant if being forced out from where the cap fits and bubbles can be seen Coolant is a dirty orange (engine flushed numerous times but still its this dirty colour) Engine oil is ok, no water mixed with it and I've no white smoke at the exhaust. So I don't suspect the head being the problem. Has anyone got any ideas ????

- (#11275) Andy, 23 Oct 03 9:57

May be lucky and have a duff rad cap or expansion tank hose see Ace Answers Archives. Otherwise suspect the head gasket.
Dirty orange - rust or rust and fuel?

- (#11276) Clive, 23 Oct 03 10:12

I have a horrible feeling that orange coolant is a sign that the transmission fluid is crossing over to the coolant. As the ATF is cooled within the vertical radiator, its a pound to a pinch of salt, that this is where its happening. Check your transmission fluid as well, see what that's like.
- (#11277) dave Bright, 23 Oct 03 10:53