Anti-Freeze Question

[StanC]

I've just done the two-yearly coolant flush and change on my 1996 960 3Ltr. I've gone for the usual 50:50 mix of distilled water with Volvo 'Coolant' (they don't seem to call it antifreeze these days!).

Reading the Volvo antifreeze information leaflet I note, for the first time, that whilst they recommend a 50% antifreeze/water mix they warn against a stronger than 55% antifreeze concentration. I've never seen this before.

I put 5 litres of new antifreeze into my car's cooling system (10 litre capacity system) but the cheap hydrometer I've got indicates a stronger than 50% solution - possibly due to some residue of old antifreeze.

My question is: does anyone know what harm a stronger than 55% antifreeze solution will do and why do Volvo warn against it?

Stan.

[CTCNetwork]

Hi,

I believe that you get reduced cooling with higher mixes percentages..
Generally you should be Ok up to 60% but no more. And that only for extreme cold environments.
You can always pour some out the drain plug and top up with distilled water..

A question to ask though is why did you not flush the system while you had the chance..

Des. . .

[StanC]

Hi Des,

Thanks for the reply.

I did flush the system - with distilled water - through the rad with both main hoses disconnected and through the expansion tank to the drain point down the right hand side of the engine. I kept flushing until clear water was coming out. That presumably leaves neat water in the lower sections of the system. But I could then only get about six litres of fluid into the system before it was full.

I'll get a 'proper' hydrometer and establish just what concentration of antifreeze i've got.

Thanks again,

Stan.

[CTCNetwork]

Hi,

Not that it would make much difference, but did you leave the heater on max to allow some of the coolant in the matrix to come out..?

Also, when I flushed mine, I ran the car for a while to get the water pump going and, as above, with heating full on.

There is also a drain plug at the bottom of the engine which may release more of your coolants than just the Rad pipes..

Des. . .

[Andy_Gibson]

yes if the coolant mix is too strong then you actually reduce the effectiveness of the coolant with reduced boiling point and theres more chance of the engine over heating

[niloc]

Originally Posted by CTCNetwork

Not that it would make much difference, but did you leave the heater on max to allow some of the coolant in the matrix to come out..?

3 litre = 960 = ECC. Heater valve should open anyway without vaccuum from the engine to hold it shut.

[StanC]

Thanks for the advice Guys,

Just for the record - I did keep the climate control set to max heat throughout the drain/flush/refill/bleed process and I did drain and flush via the engine drain plug that is located low down on the right hand side of the block. All this as well as disconnecting the main rad hoses and flushing the rad.

This is what I've always done every two years for the past ten years and I've always found that after I've finished flushing the system it only takes about six litres to completely refill. The first time I did it and refilled with a pre-mixed 50% solution I only managed to get about 6 litres of solution (3 litres of antifreeze) in! So, as the specs indicate a 10 litre capacity I now assume that there must be about 4 litres of clean water 'lying' undrained somewhere in the system before I start refilling.

But 4 litres undrained capacity does seem a lot - could there be some part of the system that is not properly flushed and where old antifreeze remains?

As I've done the same thing now for ten years without any problems occuring I might just leave it - better a bit too much antifreeze than too little. I only raised it in the Forum at all because the warning about not exceeding 55% was new to me - the Volvo antifreeze packaging didn't previously contain any information leaflet.

Any further comments on all this welcome.

Thanks again,
Stan.

[CTCNetwork]

Hi,

4 litres does seem an awful lot of coolant not being removed filled in.
The matrix wouldn't hold that much, maybe half that?
Unless it is hidden away in the block somewhere. Some hard to empty chambers??

niloc: All 960/V90's have ECC? Not so sure about that..

Des. . .

[StanC]

Hi again,

What I've noticed when I do the flush is that it seems to take quite a lot of distilled water to clear all the old blue/green antifreeze out of both the rad and the block so I've assumed, over the years, that quite a bit of clean water remains in the system after flushing. Still think that 4 litres is a lot, though.

I'd love to know what other owners of 960/S90 3 ltr 24v have experienced when doing coolant changes.

Stan

[Crispy-d]

I bought an S90 just last week, and am waiting for it to be MOTd! Once the handbrake's been sorted (seems to have ceased off) it should be fine. I have a week left to play with it in the driveway till MOT time, should I be draining the coolant system then? Is this important?