Engine coolants

[premmington]

VWG always mandated de-ionised water, if it wasn't booked out on warranty jobs, the claim would be refused. I suppose it depends on the water hardness, some areas will be OK and TBH, by the time it's starting to block up things like heat exchangers, then it'll be well out of warranty anyway and be put down to age or 'wear & tear'.
I always dilute mine with de-ionised water but then I have litres of the stuff, surplus from VWG warranty jobs...

Service coolant top-ups were and are always tap water, irrespective of brand.

This is what I do - service top ups are tap water.

If I do an anti freeze change or draining system to change parts/seal leaks - it is always 50/50 with deionised water. Water is very hard where I live.

Every eastern european I have ever known sticks antifreeze in neat - but they suffer winters that are colder.

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@Ubique - Your quote "Some - not all - aftermarket coolant is recycled" - maybe thing of the past mate - most older waste blue antifreeze now goes for mono ethylene glycol (MEG) production in the oil gas industry.

 

[Ubique]

Undiluted coolant will cause lots of longer-term problems due to the acidic nature of it, it needs to be diluted (and generally with G12+ 1:1, that protects to -34deg. C.), the dilution also helps with the heat transfer properties due to the viscosity of the 'neat' stuff.

 

[Smallfry]

I buy the ready mixed Mannol stuff now. Its is not that much more expensive than concentrate, as as I live in a hard water area, it sort of makes sense

Hopefully the guys at Mannol are not making it up with tap water

 

[premmington]

Undiluted coolant will cause lots of longer-term problems due to the acidic nature of it, it needs to be diluted (and generally with G12+ 1:1, that protects to -34deg. C.), the dilution also helps with the heat transfer properties due to the viscosity of the 'neat' stuff.

I know... 50/50...

Most coolant has corrosion inhibitors in it - or that is what the labels say

All too much chemistry for me...

 

[malcolm]

I had no idea this had become so complicated. Noticed my new project (2001 Peugeot) had red anti-freeze. Looks OK inside. The waterpump was a pain to remove when I did the timing belt and there is more brown than I would like so I'll pull the radiator to drain the old coolant (drain plug no worky and bottom hose not at the bottom) and change the coolant. I guess once it's all drained I can put what I use on everything else in? I'm better with colours than specs and the green stuff I normally use seems to stay green and not go brown. It's Prestone ready mix, silicate free and they claim it can be used in all vehicles.

Looked at their website. You can find organic acid technology coolants (OAT - normally red) and inorganic additive technology (IAT - normally green) coolants. Looks like the green one I use is OAT but magically can be mixed with the other type without jelly so should be good without a flush. - https://www.prestoneuk.com/blog/dos-and-donts-of-mixing-coolant/

 

[Ubique]

@Ubique - Your quote "Some - not all - aftermarket coolant is recycled" - maybe thing of the past mate - most older waste blue antifreeze now goes for mono ethylene glycol (MEG) production in the oil gas industry.

The blue - yes, the polythene based (H)OAT definitely gets scrubbed and recycled. TBH, I've not seen anything with Ethylene Glycol in for a long time - except the odd bottle of 'Blue Nun'...

 

[premmington]

The blue - yes, the polythene based (H)OAT definitely gets scrubbed and recycled. TBH, I've not seen anything with Ethylene Glycol in for a long time - except the odd bottle of 'Blue Nun'...

Ethylene Glycol - being withdrawn over the years nasty stuff - poisonous.

New red Propylene glycol stuff they put in makeup and food.

But have you noticed how "sticky" the red stuff is on your hands and on the floor if you have a spillage...

 

[Ubique]

Yer, sorry - Propylene, for some reason I read (and type) it as polythene!
It's really annoying in that it never dries - so a spill or residue from draining a cooling system needs washing down then a good blasting with an airline to get rid of any residue, otherwise you know damn well it'll come back as a 'suspected coolant leak' at some point in the next six months....

 

[premmington]

Yer, sorry - Propylene, for some reason I read (and type) it as polythene!
It's really annoying in that it never dries - so a spill or residue from draining a cooling system needs washing down then a good blasting with an airline to get rid of any residue, otherwise you know damn well it'll come back as a 'suspected coolant leak' at some point in the next six months....

@Ubique - My list of hates in order.

1. Gear oil - cats urine

2. CV grease - just evil stuff - transfer one tiny blob - everywhere

3. Red anti freeze - sticky stuff

4. Cars owned by single mothers with kids or motab cars - dirty

5. Taxis/traders/taliban...

6. Builders twin wheeled trucks

Of late I am getting close to adding vans to the list....

 

[Ubique]

Definitely hypoid oils at the top of the nasty list - we had an Etron in last week that had the usual coolant leak into the differential, causing the gear oil to emulsify and push it's way out along the long driveshaft tube - stunk like a dead Fox that had a decomposing Badger in it's ruptured stomach....
I've never liked working on vans....

 

[Blobber]

4. Cars owned by single mothers with kids or motab cars - dirty

 

[Turbo]

I had no idea this had become so complicated. Noticed my new project (2001 Peugeot) had red anti-freeze. Looks OK inside. The waterpump was a pain to remove when I did the timing belt and there is more brown than I would like so I'll pull the radiator to drain the old coolant (drain plug no worky and bottom hose not at the bottom) and change the coolant. I guess once it's all drained I can put what I use on everything else in? I'm better with colours than specs and the green stuff I normally use seems to stay green and not go brown. It's Prestone ready mix, silicate free and they claim it can be used in all vehicles.

Looked at their website. You can find organic acid technology coolants (OAT - normally red) and inorganic additive technology (IAT - normally green) coolants. Looks like the green one I use is OAT but magically can be mixed with the other type without jelly so should be good without a flush. - https://www.prestoneuk.com/blog/dos-and-donts-of-mixing-coolant/

Not hard to do a flush when you have the bottom hose off anyway.

Wedge a garden hose into the bottom hose with a rag wrapped around it to seal it. A hoselock qrc fitting on your garden hose is usually a good fit for a rad hose.

Remove the top rad hose and back flush the engine until the water runs clear. Open up any bleed point like the ones on the heater hose and stat housing and check you have clear water flowing.

Let as much water drain back out as possible then use an airline on any bleed points and hoses to get more out.

Likewise backflush the radiator.

If I recall your car is a 406 coupe.

I have had a 406 and a 306 with the hdi engine and they can be a pig to bleed properly. The reservoir is mounted too low in the engine bay in these cars.
I made up an extension for the coolant reservoir from a large mouthed 1 litre plastic bottle. Cut the bottom out of it and added tape around the top until it wedged tightly into the filler neck of the reservoir.
You will have to remove the small return hose from the reservoir as you have probably blocked off the end of it.

This means that you can have a head of coolant higher than the engine. Slowly add neat coolant until you have added half the system capacity. Then top up with distilled water until bubble free coolant runs from your open bleed nipples.

Keeping the extension topped up and in place run the engine until it gets warm and the stat opens. You will be surprised how much the level drops as the engine warms. Its a good idea to carefully open the bleed nipples to get rid of any trapped air.

Let it cool down then suck out excess coolant, remove the extension and leave the system back to standard.

Keep an eye on the coolant level for a few days and check the interior heater is working and the rad is heating evenly. It's not unknown to have to bleed trapped air out again.

 

[Smallfry]

Give it a dose of Sentinel X800 central heating cleaner. You will be amazed at what comes out. Then flush with clean water until clear.

 

[premmington]

Give it a dose of Sentinel X800 central heating cleaner. You will be amazed at what comes out. Then flush with clean water until clear.

If I wanna get oil out of coolant system - breached oil coolers and head gaskets of old (can't remember the last head gasket I did).

I run them up with up to temp with clean tap water and a dish washer tablet....

 

[jimbo84]

I navigated this minefield not too long ago with the Kia. No idea what was in it and wasn’t sure what to put in it.

Drained and flushed out as much as I could of the old stuff and then put in the Prestone ready mixed coolant based on its claims of being compatible with all vehicles and any existing coolant type.

Not been in long enough to allow a y issues to develop.

 

[reb78]

If I wanna get oil out of coolant system - breached oil coolers and head gaskets of old (can't remember the last head gasket I did).

I run them up with up to temp with clean tap water and a dish washer tablet....

So, I flushed my Ford digger engine out a little while back. I got a lot of what looked like mud out of the system and cleared several blockages. It's got tap water in currently which won't be doing it any good. I have ethylene glycol to go.in it but was wondering about running with something to clean it first.

Any thoughts on whether a dishwasher tab or sentinel or something else might work best? Will dishwasher tabs affect any ali parts badly?

 

[barracuda816]

If I wanna get oil out of coolant system - breached oil coolers and head gaskets of old (can't remember the last head gasket I did).

I run them up with up to temp with clean tap water and a dish washer tablet....

I would be careful with that, I think atleast the the all in one tabs have a ton of salt in them. They are not great for ally. However a short run of an hour or two and a flush would likely not do any harm.

 

[Domdom]

I have used Persil and Ariel washing machine capsules in the past which seem to get rid of oil. Dishwasher tables are also good. With any of these options you really do have to flush out well afterwards, especially with aluminium blocks or heads.