P38 Coolant - confused.com...!

P38 Monkey · Dec 1, 2022

1997 P38 4.0SE
I thought I understood the various types of coolant...
Blue/green IAT for older cars (mine currently has this colour) - change every 2-3 years.
Red/pink OAT for newer cars. Never to be mixed with IAT. Lasts indefinitely.
HOAT (yellow?) - not sure about this one but never used it.
My P38 was imported from Japan about 3 years ago so probably could do with a coolant change.
Opie Oils list IAT diluted ready-to-use for my P38 in 1L and 5L bottles. So far so good.
Then I read the P38 user handbook.
It says IAT with OAT additives is best. WHAT?!!
It also says "DO NOT top-up or refill with conventional anti-freeze formulations". WHAT?!!
Searching this forum, it seems most people use blue/green IAT and some people switch to pink OAT after major engine rebuilds etc.
Help please....!

kermit_rr · Dec 1, 2022

The blue green stuff was all that was available when the engine was designed. The more modern OAT came in later and it's what land rover choose because of the service interval. It still needs changing but reckoned to last up to 10 years, i think. I use the green, but i think both are ok

P38 Monkey · Dec 1, 2022

kermit_rr said:
The blue green stuff was all that was available when the engine was designed. The more modern OAT came in later and it's what land rover choose because of the service interval. It still needs changing but reckoned to last up to 10 years, i think. I use the green, but i think both are ok

Yes, that is as I understand it, with the proviso that people say you can't mix IAT and OAT as it apparently forms a gel and blocks the radiator.
The P38 handbook refers to Havoline XLC which is OAT so I guess that is the one to use, mixed 50/50.
I'll switch to XLC with a good flushing out at some stage.
Might fit a new thermostat at the same time to make the flushing easier.

Rubberknees · Dec 1, 2022

P38 Monkey said:
1997 P38 4.0SE
I thought I understood the various types of coolant...
Blue/green IAT for older cars (mine currently has this colour) - change every 2-3 years.
Red/pink OAT for newer cars. Never to be mixed with IAT. Lasts indefinitely.
HOAT (yellow?) - not sure about this one but never used it.
My P38 was imported from Japan about 3 years ago so probably could do with a coolant change.
Opie Oils list IAT diluted ready-to-use for my P38 in 1L and 5L bottles. So far so good.
Then I read the P38 user handbook.
It says IAT with OAT additives is best. WHAT?!!
It also says "DO NOT top-up or refill with conventional anti-freeze formulations". WHAT?!!
Searching this forum, it seems most people use blue/green IAT and some people switch to pink OAT after major engine rebuilds etc.
Help please....!

Use the orange/red one in my doozle. Thats what local indy recommended when he changed my engine 6 years ago

P38 Monkey · Dec 1, 2022

Rubberknees said:
Use the orange/red one in my doozle. Thats what local indy recommended when he changed my engine 6 years ago

Thanks for that - looks like my P38 has IAT when it is best to have OAT. I'll drain, flush and refill with Havoline XLC OAT.
As ever, actual experience of people in this forum is invaluable.

kermit_rr · Dec 1, 2022

P38 Monkey said:
Thanks for that - looks like my P38 has IAT when it is best to have OAT. I'll drain, flush and refill with Havoline XLC OAT.
As ever, actual experience of people in this forum is invaluable.

the only difference is the interval, they both do the same job

easy-shaft · Dec 2, 2022

Is it true that the pink does less damage to your carpets?

Grrrrrr · Dec 2, 2022

P38 Monkey said:
1997 P38 4.0SE
I thought I understood the various types of coolant...
Blue/green IAT for older cars (mine currently has this colour) - change every 2-3 years.
Red/pink OAT for newer cars. Never to be mixed with IAT. Lasts indefinitely.
HOAT (yellow?) - not sure about this one but never used it.
My P38 was imported from Japan about 3 years ago so probably could do with a coolant change.
Opie Oils list IAT diluted ready-to-use for my P38 in 1L and 5L bottles. So far so good.
Then I read the P38 user handbook.
It says IAT with OAT additives is best. WHAT?!!
It also says "DO NOT top-up or refill with conventional anti-freeze formulations". WHAT?!!
Searching this forum, it seems most people use blue/green IAT and some people switch to pink OAT after major engine rebuilds etc.
Help please....!

Colours aren't consistent so make sure you read the ingredients.

P38 Monkey · Dec 2, 2022

Grrrrrr said:
Colours aren't consistent so make sure you read the ingredients.

Yes, apparently Honda colour all their badged coolants blue. I just wish I knew what type is in there already!

romanrob · Dec 4, 2022

easy-shaft said:
Is it true that the pink does less damage to your carpets?

LOL... the pink comes out, for sure

Mark Piercy · Dec 5, 2022

Both me ad my son have run pink and yellow antifreeze, no worries with either tbh.

Grrrrrr · Dec 6, 2022

Mark Piercy said:
Both me ad my son have run pink and yellow antifreeze, no worries with either tbh.

Is that like yellow snow?

kermit_rr · Dec 6, 2022

Grrrrrr said:
Is that like yellow snow?

Only in Scotland

Mark Piercy · Dec 6, 2022

Grrrrrr said:
Is that like yellow snow?

Maybe round you way mate

Grrrrrr · Dec 6, 2022

Mark Piercy said:
Maybe round you way mate

My last but one lot was green and the last lot pink. Same with the coolant.

Apparently the same stuff from the same manufacturer.

Mark Piercy · Dec 6, 2022

From I've seen and dealt with yellow/green is popular with renault and older Citroëns. Pink is popular with vw group and modern Citroën and peugeot. Mercs like the blue type.. Toyota typically orange.

Jon Dor · Dec 7, 2022

Grrrrrr said:
Is that like yellow snow?

It tastes (allegedly) better than yellow snow...but that's NOT a challenge for you

dubbleRR · Dec 7, 2022

Jon Dor said:
It tastes (allegedly) better than yellow snow...but that's NOT a challenge for you

THE weather man said it was a YELLOW ,,,snow warning on the telly last night for scotland ,

,,,not seen any yet ..

..

Grrrrrr · Dec 8, 2022

dubbleRR said:
THE weather man said it was a YELLOW ,,,snow warning on the telly last night for scotland ,,,,not seen any yet ....

Wait until the pubs kick out, assuming they do still close in Scotlandshire.

Scotiawhiskers · Dec 9, 2022

Otto was on pink coolant when we got him, having not long had a rad and waterpump apparently. So that is what we've stuck with and he seems fine. 4.0 GEMS V8.

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