Incorrect Antifreeze - To Stick or To Change!

[Clan]

Originally Posted by riffbiker

1996 Volvo 850 - 2.5 20v Petrol 170 BHP B5254S Engine

I have to replace the heater matrix on my car and intend to drain down the cooling system to help reduce spillage into the cabin. The antifreeze being used is Orange / Red in colour and having just spoken with the professional mechanic who filled it 9 years ago when he fitted a radiator - it is likely GM Dex-Cool OAT!!! I had no idea !!! This should never have been put in - but it was and to date does not appear to have caused problems.

So:
Radiator: 9 years old (after-market brand fitted by said mechanic)
Water Pump: 3 years old (OE Volvo)
Expansion Tank & most hoses: 3 years old (OE Volvo)
Heater Hoses - original (24 years old - appear OK and are expensive to buy)
Running Dex-Cool OAT: originally 9 years ago diluted with hard tap water by professional mechanic, with a flush and complete refill with same Dex-Cool OAT diluted with distilled water 3 years ago
New Heater Core going in imminently

I intend to drain the cooling system anyway to replace the heater core. What do you recommend, to flush and refill with Dex-Cool / OAT so as not to change and hence risk a mix of type ...

- OR flush, fill with distilled water and flushing agent and run for a few days, drain and refill with genuine Volvo V031439724 coolant (I buy at the trade counter of my Volvo dealership) which is probably HOAT ... it seems Volvo do not say what it is.

Can you recommend a suitable flushing agent if so?

Would to change now be more potentially damaging than to continue with Dex-Cool / OAT with which I am unaware of any problems - it is still relatively but not completely clean in the expansion tank after three years?

Thanks, RB

Just flush and add volvo coolant 50-50 it will not need changing again and is the best quality and value out there .


Volvo Coolant is the only coolant adapted for and approved
by Volvo and ensures continual good performance from the
cooling system. The product gives very good protection against
corrosion and is particularly kind to light-metal alloys inside the
engine. Does not contain nitrites, amines or phosphates.
The various part numbers contain the same product and the
packaging is adapted to suit the requirements of different
markets. The bottles are equipped with child-resistant caps.
Contains ethylene glycol, inhibitors and denaturant.
Coolant in drums should be ordered by the litre.

Technical data
Colour: Blue
Density at 20 °C: 1.12 g/cm³
Viscosity at 20 °C: 24 to 28 mm²/s
Boiling point: min. +165 °C
pH: 7 to 7.5
Maximum antifreeze
protection:
-51 °C (104°F)

[riffbiker]

@Clan: Many thanks and appreciate your response!

I have already procured the heater core / heat exchanged for which, due to cost I opted for a German BEHR at about 1/4 the price of OE Volvo - now branded Mahle Behr #AH106000P (8FH 351 311-751) as Mahle have bought out Hella's share. I am led to believe that Behr were OE suppliers to Volvo (for the 850 / V70) in the first place...

'O' rings and coolant on order at my Volvo Parts Counter. 25 litres of deionised water for flushing en-route!

Thanks for the Volvo Tech. spec. - however this changing of colours across manufacturers and brands is extremely and unnecessarily 'confusing' - hence my original dillema. Didn't Volvo coolant used to be green?

If it really is 'never needs changing' (great) then although Ethylene Glycol based, it sounds more like HOAT than IAT ?

Kind Regards, RB

[Clan]

Originally Posted by riffbiker

@Clan: Many thanks and appreciate your response!

I have already procured the heater core / heat exchanged for which, due to cost I opted for a German BEHR at about 1/4 the price of OE Volvo - now branded Mahle Behr #AH106000P (8FH 351 311-751) as Mahle have bought out Hella's share. I am led to believe that Behr were OE suppliers to Volvo (for the 850 / V70) in the first place...

'O' rings and coolant on order at my Volvo Parts Counter. 25 litres of deionised water for flushing en-route!

Thanks for the Volvo Tech. spec. - however this changing of colours across manufacturers and brands is extremely and unnecessarily 'confusing' - hence my original dillema. Didn't Volvo coolant used to be green?

If it really is 'never needs changing' (great) then although Ethylene Glycol based, it sounds more like HOAT than IAT ?

Kind Regards, RB

yes it was green from the 70's to about the mid 90's , probably when the 850 came out . when it went blue/green .
I have been using it in all my cars since the 70's I dont take any notice of other coolant ..
My 1988 343 still has the original green type .. still strong down to -37C and clear as the day it was added in the factory

[4x4]

Not sure whether this is classed as green or blue (it looks more green to me) but only a couple of months old and genuine Volvo so make up your own mind

[riffbiker]

@ 4x4: It looks green to me. Thanks for your help.

[cheshired5]

Originally Posted by riffbiker

I would advise anyone NOT to pour neat undiluted antifreeze into any engine in quantity, but to pre-dilute it to strength with distilled water. Antifreeze has a very 'searching' effect and if a system is going to develop a leak, it will after a coolant change.

With my suggested method, you're adding 50% capacity of neat coolant to the residual water that's inevitably left in the system and you're immediately adding water on top as well as running the engine to mix and circulate.
The concentrated coolant is never truly neat in the system so will cause no issues and is the best way to guarantee a 50/50 mix.

For reference, this is my coolant 5 years after using my regular method and no top ups have ever been needed.



Putting 50/50 premix coolant into an "empty" system which actually contains a quantity of water means that your final mix will be diluted to less than 50/50.

[4x4]

Check your owner's manual for the cooling capacity then before you refill for the final time after flushing put 50% of what the manual states into the cooling system and top off with distilled or deionised water

[riffbiker]

@Cheshired5: That is mightily clean antifreeze / coolant. I have the OE Volvo Ready Mix coolant on order my Volvo Trade Counter, together with OE 'O' rings (back-order) for the heater pipes to heater core / heat exchanger on order.

My Volvo dealer gave the part number for the coolant (# V31439724 : 4 litres ready mixed) which is what THEY use in their accredited workshops. I do take your point about the different fill methods and you are, of course, correct. For myself I still would not put 50% neat antifreeze into especially an old system even if mathematically correct. A 50% mix antifreeze to deionised water ratio will take the frost protection to way below what we will ever see in the UK, so if the final mix ends up being a fraction less I don't see it as significant.

I have tended to run on a 33% mix ratio anyway - which IF it is Dex-Cool filled in my car, might prove to be to my advantage - less Dex-Cool!

I am sceptical about 'never having to change antifreeze' - even if topped up with neat antifreeze occasionally and the specific gravity measured with a hydrometer for frost level protection. The additives that provide the anti-corrosion, deteriorate and can even be 'sacrificial' as they perform their chemical magic with the alloys of the engine. So it could be possible to have coolant that still protects against frost but has weakened anti-corrosion capabilities. There is normally a specification for longevity between coolant changes written on the coolant packaging - I shall be interested to see what OE Volvo specifies ...

All that noted though, you have very clear coolant! I look forward to getting mine done as my Volvo is VOR (Vehicle Off Road) - I dare not risk using it.

Will let you all know how it goes when I do the job after the parts arrive. Thank you all for you kind and greatly appreciated help! RB

[Clan]

Originally Posted by riffbiker

@Cheshired5: That is mightily clean antifreeze / coolant. I have the OE Volvo Ready Mix coolant on order my Volvo Trade Counter, together with OE 'O' rings (back-order) for the heater pipes to heater core / heat exchanger on order.

My Volvo dealer gave the part number for the coolant (# V31439724 : 4 litres ready mixed) which is what THEY use in their accredited workshops. I do take your point about the different fill methods and you are, of course, correct. For myself I still would not put 50% neat antifreeze into especially an old system even if mathematically correct. A 50% mix antifreeze to deionised water ratio will take the frost protection to way below what we will ever see in the UK, so if the final mix ends up being a fraction less I don't see it as significant.

I have tended to run on a 33% mix ratio anyway - which IF it is Dex-Cool filled in my car, might prove to be to my advantage - less Dex-Cool!

I am sceptical about 'never having to change antifreeze' - even if topped up with neat antifreeze occasionally and the specific gravity measured with a hydrometer for frost level protection. The additives that provide the anti-corrosion, deteriorate and can even be 'sacrificial' as they perform their chemical magic with the alloys of the engine. So it could be possible to have coolant that still protects against frost but has weakened anti-corrosion capabilities. There is normally a specification for longevity between coolant changes written on the coolant packaging - I shall be interested to see what OE Volvo specifies ...

All that noted though, you have very clear coolant! I look forward to getting mine done as my Volvo is VOR (Vehicle Off Road) - I dare not risk using it.

Will let you all know how it goes when I do the job after the parts arrive. Thank you all for you kind and greatly appreciated help! RB

That is false economy buying it ready mixed its more expensive . They use it in their workshops to make more money! Most honest volvo workshops use the concentrated . Just buy a 4 litre bottle of concentrated and mix it yourself .

Have no worries whatsover about the life of volvo coolant , trust me i have been using it in all sorts of cars from the 1970's .. It keeps its -37 C freezing rating and the corrosion inhibitors stay in grade . That's why i said its the very best quality and the most economic to buy .

[riffbiker]

@Clan: Thank you! Really appreciate your kind response! Best Regards, RB