The best 300 tdi coolant

So my defender was involved in an accident and it involved a new radiator to be installed. The garage has done an excellent job. However I’ve noticed that the coolant that’s been put in it is red and I’ve heard that red can be very bad for an engine with an aluminium head and it can cause corrosion on the other aluminium parts?

There’s a lot of conflicting information online, but the general consensus is that red stuff is for a TD5 or later and that the TDI era should be on blue is this the Case?

I’ve normally always put in blue two year ethylene glycol based coolant non AOT, so I’m not sure why red was chosen?

The other issue I have is now that it’s got red inside I’m no longer able to use my two blue top up bottles that are brand new if I ever needed to do this during a long drive or coolant loss or something you just don’t know.

Can anyone tell me if I should swap this red out immediately or I will it be okay thanks, Ryan

Just a bit worried, it could cause long-term engine damage or something if I leave it in

I personally would use blue, but I bet there are loads of older ones on the OATs stuff, it is not the aluminium head that is the issue, in fact it is not any metals at all that are the problem, it is mainly paper gaskets and the like.

If you do change it, remember there is a bleeding procedure you must follow for the 200 and 300tdi.

I use OAT long life (the red stuff) and don't have any problems. The Ethylene Glycol provides good corrosion resistance and doesn't effect or damage alluminium or iron/steel at all.
It's also relatively inexpensive and pretty much available anywhere.

miktdish said:

I use OAT long life (the red stuff) and don't have any problems. The Ethylene Glycol provides good corrosion resistance and doesn't effect or damage alluminium or iron/steel at all.
It's also relatively inexpensive and pretty much available anywhere.

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So you think be okay with red in?

Do you have any recommendations for a small top up bottle?

Your best option would be to get some from the garage who did the work, not all red is the same.
Most surprised that red would damage aluminum due to modern vehicles having Ali engines.
I thought it was more to do with brass (?) radiators?
We use the blue coolant, although you need to change it more often.
Probably not that important along as you don't mix types, have to change it again when timing belt is changed I guess.

I would probably disagree with you there @Anaconda Red coloured OAT santifreeze can be safely mixed with other Red antifreeze but shouldn't be mixed with Blue or Green.

Red is an Organic Acid Technology formulae, different manufacturers may have different addatives for corrosion resistance etc but basically all Red OAT antifreeze can be mixed together with other manufacturers Red antifreeze.
It lasts longer than the other colours too.

Typical mix is 50:50
A small bottle ... I don't bother, everynow and then I look in the expansion tank aned haven't needed to add any for the last couple of years.

lynall said:

I personally would use blue, but I bet there are loads of older ones on the OATs stuff, it is not the aluminium head that is the issue, in fact it is not any metals at all that are the problem, it is mainly paper gaskets and the like.

If you do change it, remember there is a bleeding procedure you must follow for the 200 and 300tdi.

Click to expand...

Another vote here for blue. But I don't have anything new enough to be anything but blue so I make sure everything is running the same so I only need to keep one fluid on the shelf as spares.

miktdish said:

I would probably disagree with you there @Anaconda Red coloured OAT santifreeze can be safely mixed with other Red antifreeze but shouldn't be mixed with Blue or Green.

Red is an Organic Acid Technology formulae, different manufacturers may have different addatives for corrosion resistance etc but basically all Red OAT antifreeze can be mixed together with other manufacturers Red antifreeze.
It lasts longer than the other colours too.

Typical mix is 50:50
A small bottle ... I don't bother, everynow and then I look in the expansion tank aned haven't needed to add any for the last couple of years.

Click to expand...

You are probably right, it's the manufacturers stating its different and not compatible so you go and buy their one.
Mine was yellow/gold on the 05 Mustang, not so straight forward to buy over here.

Yellow is the Hybrid OAT (HOAT) antifreeze.
Not compatible with Red or Green.

Found this .....

HOAT and OAT coolants protect differently. HOAT coolant lay down a protective layer on the surface while OAT use an electro-chemical reaction to protect the surface. If there is something that causes corrosion to quickly form, like chloride ion in the system, OAT coolant can not fight the corrosion as well as a HOAT coolant. This is one of the reasons why its a good idea to use Di water in the coolant. If the HOAT protective coating is broken, it does not protect the surfaces. This is not a problem in OAT coolant.

Which kinda seems to tell me that good old Red OAT antifreeze is good enough and as long as I change it every 5 years it works well enough in all my cars.
If I do ever start racing in the desert or parking the car up in below -30C temperatures then I will think again.

My Focus came with red antifreeze rated to be good for 10 years. Strangely Ford said that when it was due to be changed it would only be good for 5 years before needing changing again ?