How important is coolant antifreeze/water ratio ?

[maartenvd]

Originally Posted by Semnoz

Thanks for all the answers - that's made my mind up to renew all the coolant.

Apparently it's not a simple job though due to potential air-blocks. Or can it be done DIY ?

My xc70 185 still has the original coolant in it, and over the years it has lost the green color, looks more colorless now. So I am also planning to do a flush based on Sirobb's coolant flush video. Any extra advice on how to do this properly on a P3 v70/xc70?

[green van man]

Drain plug on lower left hand side of radiator when looking from drivers seat. Turn heater to hot.
Open drain plug let it run till it stops, refit, fill with water, run engine for short while, stop engine, open drain plug and repeat until clear water comes out the radiator. If you have access to a hose pipe put that in the filler with the drain open then close the drain and run the engine.
Drain again and refill with 50/50 coolant. Test run and check level.

It's what I did on my D5 and had no problems.

I prefer to calculate 50% of capacity and add neat coolant then fill with water, that way any water in the system is taken into calculations and a true 50/50 mix obtained.

On my P1 I did get a slight air lock, warmed the car up on a test run stopped and opened the filler gently, gurgling and spluttering and water level dropped in header tank as airlock cleared, filled to mark and no problems in the 12 years I had the car.

Paul.

[Laird Scooby]

Originally Posted by green van man

I prefer to calculate 50% of capacity and add neat coolant then fill with water, that way any water in the system is taken into calculations and a true 50/50 mix obtained.

Only way to do it and get it right Paul!

[chrisfr]

If you buy a specific gravity tester this may tell you the ratio but also the - degree c that the water will freeze at. Too low a freezing point and you need to top up with water, too high and you top up with antifreeze. They usually have a green zone which means freezing temperature and ratio are perfect as long as the reading is in there.

[Laird Scooby]

Originally Posted by chrisfr

If you buy a specific gravity tester this may tell you the ratio but also the - degree c that the water will freeze at. Too low a freezing point and you need to top up with water, too high and you top up with antifreeze. They usually have a green zone which means freezing temperature and ratio are perfect as long as the reading is in there.

Very good idea if the antifreeze has been in a while!

I think the OP in this case needs to do a full flush because he mixed various types and had a leak as well.

Only way (once the leak is fixed) to be sure is to give it a full flush and refill with fresh ethylene glycol and water using Pauls method above ^^^^^

[Semnoz]

This is turning out to be more annoying than I'd thought.

I've removed the top-up tank cap, filled it with water (from garden hose), and opened the radiator drain valve....and nothing comes out.

I then looked at removing the lower main hose from the radiator and cannot figure out how it comes off. I've removed the metal 'spring clip' on the hard plastic section at the end of the hose, but this made no difference. The Haynes manual assumes this engine has jubilee clips on the main hoses, so is of no use at all.

Anyhow, I've now also tried turning the engine over for a few seconds (with the heater temp set on Hi). The top-up tank is staying full of water, and still nothing coming out the radiator drain.

This makes me think I'm doing something fundamentally wrong......but can't think what.

The only thing I can think of is that the thermostatic valve isn't opening (as engine is cold) and I can't flush water through until this opens. But as I'm not sure if there's much coolant in the engine, I'm not comfortable running it like this. And besides, all the guides I've read suggest you can fully top up the coolant with the engine cold, run the engine, let it cool down, and then drain the coolant, and then top it up and repeat until clean water comes out. So what am I doing wrong ?

[Laird Scooby]

That doesn't bode well - suggests your mixing of antifreeze types has caused some gelling!

[Semnoz]

Originally Posted by Laird Scooby

That doesn't bode well - suggests your mixing of antifreeze types has caused some gelling!

I only ran the car for about 15 minutes having put some orange anti-freeze in (about 3/4 litre), and then once home, a few litres of coolant came out when I removed the broken hose. The car has been sat on the driveway since. I can't imagine anything could become clogged up that easily.

[Laird Scooby]

It doesn't take a lot. I know of a 1994 V6 that was put into a garage for the water pump and timing belt to be changed.
Firstly the garage mis-timed the cam belt and secondly they refilled it with OAT (red) coolant.

The owner took it back to them because it was running rough, they re-timed the cam belt and away he went. Within a week or so both head gaskets had blown. Why? Because although the garage had drained the system some ethylene glycol remained. This reacted with the OAT and formed a gel.

The person who took the job on spent many hours just cleaning the gel out of various parts of the engine, cooling system, throttle body, cold start fast-idle valve etc without all the time he spent sorting the head gaskets.

Imagine it or not, it can and does happen! I'd be very glad to be proved wrong (and i hope i am) but all i'm saying is that it doesn't bode well if the drain taps won't issue fluid.

[Semnoz]

I think it's all OK now.

In short: 5 flushes with water, filled with antifreeze concentrate, hot air blows out heater, radiator hoses get hot, car is driving fine, top-up reservoir remains at max.

Long version: I managed to remove the lower radiator hose, and the coolant drained out. It would appear the radiator drain doesn't do anything, so I'll just ignore that from now on.

I've now flushed clean water through the engine and radiator about 5 times until it's coming out clear. In between top-ups, I had the engine running for a minute with the heater set to Hi (max).

What I've noticed is that the most coolant I can drain out the system is around 4.5 litres. If the handbook is correct and the entire system requires 12.5 litres, it would seem that either:

1) 8 litres of fluid cannot be drained, presumably because it's stuck in the heater matrix, engine block pockets etc...
2) I have a big air-block

Anyhow, after one final drain of the coolant fluid, I proceeded to slowly fill up with blue antifreeze concentrate. I got about 4.2 litres into the system before it reached the max mark. I also had the top hose disconnected from the thermostat body, and waited until I could see blue liquid appearing in the clear water that was trickling through, and I also tried topping up the radiator with antifreeze solution, but it must have been full of water as I only managed to top up the hose (the 4.2 litres includes topping up the top hose).

I then drove the car around for about 10 minutes, and checked the top-up reservoir and it was still at max. Given that the top-up reservoir itself holds at least a litre, it's clear that there isn't a 50/50 mix of water/antifreeze circulating through the engine. If I can't drain at least 50% of the 12.5 litre capacity, I'm not quite sure how I'll ever achieve the recommended 50/50.