What kind of coolant to use?

[Astrodonkey]

Hi all,

I just bought a 1997 V6 Camry LE. The coolant is running low. I was going to top it off but noticed the expenasion tank orange coolant in it. The user's manual says to use ethylene-glycol coolant, which I believe is the green stuff, is it not? I don't know the differences between the two coolant types, but I don't think they're compatible.

Which one should I use, and why would the orange stuff be in there in the first place?

[Astrodonkey]

Ummm, answered my own question with this thread:
http://www.toyotanation.com/forum/t22782.html

Missed it on my first search.

Looks like I should use the orange, but I'm still confused since the owner's manual says to use ethelyene-glycol.

[CX889]

I use the green one.

[white3ch0c0late]

Toyota engines are made to use DexCool (red) coolant only. It protects the aluminum heads. The silicates in the green coolant corrode the heads.

[Astrodonkey]

Hmmm. In the thread above, someone said Dexcool is not the same as the red Toyota coolant.

[terrastrife]

i have green in my 3vz fe -- if hte motor dies, what an excuse to power it up!

[Ken4]

Best to use Toyota Red Premix. There are many on the market, make sure to use the right one:

Originally posted by Marty:
I did a lot of research when we bought a new 2002 Toyota. My previous vehicles had been converted to DEX-COOL ('90 Honda, '90 VW - no problems at all). I found this on a UK website:

Anti-Freeze: What are the different types and properties?

There are currently five main types of antifreeze. In all cases the 'anti-freeze' properties last the life of the coolant - it is the various additives that deteriorate with time. These additives include anti-foaming agents, surfactants (to improve the 'wetting' of the coolant and hence give better heat transfer) and, most importantly, anti-corrosion additives. As the range of alloys and plastics used in modern engines grows ever more complex it is important to ensure that the correct anti-freeze is used.

1. Ethylene Glycol - this is the traditional stuff, used since the 1950's. It uses silicates to stop corrosion by passivating the metal surface. This type of anti-freeze is suitable for most European cars, but not Japanese cars. Japanese manufacturers normally recommend a low- or no-silicate formulation due to the nature of the seal materials that they use (see below).
Typical service life of 2-4 years.

2. Ethylene Glycol: Low- or no-silicate formulation. This is specified by most Japanese cars. OEM Nissan, Toyota 'red' etc. antifreezes use phosphates rather than silicates to inhibit corrosion. Silicates are abrasive and the use of high silicate antifreezes in Japanese cars may result in premature failure of seal materials.
Typical service life of 2-4 years.

3. Mono Propylene Glycol - this still uses silicates and is claimed to last 4 years. Mono Propylene Glycol does not conduct heat as well as Ethylene Glycol and currently carries NO recommendation from any major car manufacturer- and some actually caution against it. The main claim to fame for Mono Propylene Glycol is that its less toxic than Ethylene Glycol.
Typical service life of 2-4 years.

4. Organic Acid Technology (OAT) - e.g. GM 'DexCool'. Introduced in 1995, this is a recyclable and biodegradable antifreeze which is based on organic acids and is silicate- and phosphate-free. However, due to the nature of the chemicals used, it can attack certain seal and gasket materials and therefore should only be used in vehicles for which it is factory specified.

OAT antifreeze MUST NOT be mixed with the types listed above - if you wish to switch to OAT type then the cooling system must first be chemically flushed.

The claimed service life of the corrosion inhibitor package is about 5 years, or 100-150,000 miles.

5. Ethylene Glycol-based 'Hybrid Organic Acid Technology' (HOAT). Uses Ethylene Glycol, but with OAT-based corrosion inhibitors and some added silicates; most usually BASF's "Glysantin" additive package is used (also known as 'G-05'). HOAT is less agressive than straight OAT anti-freeze and has better cavitation resistance. Again, best to thoroughly flush your system if switching to it.
Lasts 4-5 years.

The bottom line is to refill your engine with what the factory supplied and do a flush-and-refill every 4 years maximum. If you have a Japanese car, stick to the maker's brand since non-OEM coolants may contain higher levels of potentially damaging silicates.

If mixing your coolant from a 'concentrate' then use demineralised or distilled water (available from motor factors at around £3 for 5 litres) to make up the quantity - UK tap water often has a lot of dissolved minerals in it which can leave scale deposits inside the engine's coolant passages.

I was planning on moving the Toyota over to either DEX-COOL or G-05 when it came time to service it - mainly because I don't want to be hostage to Toyota Parts Division.

Another good article:

http://www.motorage.com/motorage/art....jsp?id=156227