DIY: Coolant Flush ---> Quick Method via Upper Hose...

[cn90]

OK,

I have done this on multiple Volvos over the years by disconnecting the LOWER rad hose.
I am getting older and hate dealing with the LOWER rad hose.

This is the DIY via UPPER rad hose, which you can do in your Tuxedo lol...

Tools/parts:
- Definitely need the 7-mm socket for the hose clamp bc it is in awkward location.
- Distilled water (Walmart, Target etc.): 2 gallons; about $1.50/each gallon.
- Prestone Green concentrated coolant (do not use the premix 50-50): 2 gallons; $10.50/gallon @ Walmart.

Per the thread below, cooling system capacity is 8.8L / 9.3qt:

viewtopic.php?t=97040

- Take this opportunity to remove the coolant reservoir to clean it (optional).

- Anyway, once the UPPER rad hose is d/c'd, pour distilled water into the reservoir.
- Distilled water will flow from reservoir ---> bottom hose ---> engine block (RED arrows).
- Some distilled water will flow via the small round hose (YELLOW arrows).

- After one gallon of distilled water, you should see clear water flowing out of the upper rad neck.
- I added another 1/2 gallon of distilled water, so total about 1.5 gallons.
You can use the entire 2 gallons too. But I saved 1/2 gallon for later use.

- Now, the block contains mostly distilled water.
- For the typical 50-50 mix, you need to use ~ 4.5 qts at factory. This is not factory, so I improvise.
- After 1 gallon of pure concentrated antifreeze, you will start to see the green color coming out of
the upper rad neck. Then I pour another 1/2 gallon pure concentrated antifreeze, so now I have
used 6 qts, some of which will continue to flow out of the upper rad neck. When the level in the reservoir
is just above Max, I reconnected the UPPER rad hose and tighten the clamp.

- Test drive around the blocks near your house, wait for engine to cool, then if necessary, add more coolant.

- The reservoir now contains pure concentrated antifreeze, but no worry, after some hundreds of
miles of driving, it will be mixed.
- Best is to do it before winter, such as now (Sept-Oct) bc in a few months, it will be nicely mixed.

- Then after a few months, check the coolant strength.
- This is kind of "cheating" but it works for me, it is much better than fooling around with the LOWER rad hose.
- Sure this is not a perfect science but it works for me.

HTH...

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S60-Coolant-Flush-01.jpg (65.75 KiB) Viewed 3064 times

[MoVolvos]

OK,

I have done this on multiple Volvos over the years by disconnecting the LOWER rad hose.
I am getting older and hate dealing with the LOWER rad hose.

This is the DIY via UPPER rad hose, which you can do in your Tuxedo lol...

Tools/parts:
- Definitely need the 7-mm socket for the hose clamp bc it is in awkward location.
- Distilled water (Walmart, Target etc.): 2 gallons; about $1.50/each gallon.
- Prestone Green concentrated coolant (do not use the premix 50-50): 2 gallons; $10.50/gallon @ Walmart.

Per the thread below, cooling system capacity is 8.8L / 9.3qt:

viewtopic.php?t=97040

- Take this opportunity to remove the coolant reservoir to clean it (optional).

- Anyway, once the UPPER rad hose is d/c'd, pour distilled water into the reservoir.
- Distilled water will flow from reservoir ---> bottom hose ---> engine block (RED arrows).
- Some distilled water will flow via the small round hose (YELLOW arrows).

- After one gallon of distilled water, you should see clear water flowing out of the upper rad neck.
- I added another 1/2 gallon of distilled water, so total about 1.5 gallons.
You can use the entire 2 gallons too. But I saved 1/2 gallon for later use.

- Now, the block contains mostly distilled water.
- For the typical 50-50 mix, you need to use ~ 4.5 qts at factory. This is not factory, so I improvise.
- After 1 gallon of pure concentrated antifreeze, you will start to see the green color coming out of
the upper rad neck. Then I pour another 1/2 gallon pure concentrated antifreeze, so now I have
used 6 qts, some of which will continue to flow out of the upper rad neck. When the level in the reservoir
is just above Max, I reconnected the UPPER rad hose and tighten the clamp.

- Test drive around the blocks near your house, wait for engine to cool, then if necessary, add more coolant.

- The reservoir now contains pure concentrated antifreeze, but no worry, after some hundreds of
miles of driving, it will be mixed.
- Best is to do it before winter, such as now (Sept-Oct) bc in a few months, it will be nicely mixed.

- Then after a few months, check the coolant strength.
- This is kind of "cheating" but it works for me, it is much better than fooling around with the LOWER rad hose.
- Sure this is not a perfect science but it works for me.

HTH...

---
S60-Coolant-Flush-01.jpg

S60-Coolant-Flush-02.jpg

.
You owe me a Tuxedo !
.

[erikv11]

Some comments:

- I agree, accessing the lower rad pipe is a hassle especially with the splash guard in the way. It's practically as hard as changing the oil.

- Draining 3-4 gallons out the top radiator pipe will make a big sticky mess in the engine bay and on the ground underneath. Presumably you cleaned up with hose water or something?

- Similarly, please take a few minutes to cover/protect the alternator if you're going to try this method.

- I don't use green coolant, I use Zerex G05 or Volvo coolant which are the same formulation. Either of those is about $20/gallon for concentrated.

- This method will increase the coolant to above 50:50 mix (more coolant, less water) which should work out just fine but I don't like the idea of not knowing what's actually in there.

For me, I'll keep accessing the lower rad pipe, flushing the system completely, then refilling to known 50:50. But this method may be preferable for some, I can see that.

[cn90]

- Actually I did it slow with plastic container to collect the coolant/water that flows out the upper rad neck.
The flow is actually very slow like a trickle, so no spill to alternator.

- Even with the lower rad hose technique, there is also uncertainty regarding mixture %.

- I have done it this way a few times and 2 months and thousands of miles later, the coolant tester checked it out to be ~ 55% coolant and 45% water. Good enough for me.

[br0dy519]

Finger loosen and finger tighten plastic petcock for me on the rad... won't ever be touching the engine block petcock though. Always good to have multiple ways to tackle it though.

[cn90]

The petcock is notorious for breaking in old rad.
This is why I don't touch the plastic petcock.

[erikv11]

.. Always good to have multiple ways to tackle it though.

this

[erikv11]

...
- Even with the lower rad hose technique, there is also uncertainty regarding mixture %.
...

I think you already know this but regardless of which hose, petcock etc, the technique to avoid uncertainty is to:
(1) first flush completely, until pure water is running out. Flush, re-close the system, run the engine, then flush again.
(2) When there is nothing but water in there, drain a bunch from the radiator, add 1/2 capacity concentrated coolant, top up with water.
(3) drive, check, top up with water.
Then you know exactly mixture what you're ending up with. Yes, use distilled water for all of that.

[cn90]

For ppl new to this coolant flush, it is important to find out what you want to achieve in terms of coolant strength: 40%, 50% or 60% and the lowest freezing temp it protects.

If you live in Florida or Texas, even 40% is fine for 99% of the time. But you never know the car may be driven all the way north in Dec/Jan/Feb visiting family/skiing in N. Dakota, Calgary etc etc and you forgot that you use 40%. Now you happen to run into one of the coldest days of the year with temp down to -35C etc. This has cost a few ppl an engine from freezing damage. So be mindful of this fact if you travel north in the winter...if you do so, check coolant strength a few months after the flush.

Couple points:

1- Zerex 100% is ~ $20 at Walmart, Prestone 100% is about $10.50. So Zerex costs twice.

2- Engine drain block (with the bolt) in most cars usually seizes with time and is universally in an awkward location.
This is usually in the lowest spot. But most ppl avoid playing with this bc of location and bolt seizing.

3- The LOWER rad hose: when draining from here, and after a distilled water flush, there is always some water in the engine block bc the lower rad hose connection (on the engine side) is not at the lowest point in the engine.

Now, if you use 50-50 premix stuff, then chances are you end up with something like 40-45% bc of some distilled water remaining in the block. Probably OK for most ppl, but again be mindful of extremely cold temp.

Also, you simply don't know what the previous mechanics or P.O. used. The heater core contains a little bit too.

4- The plastic petcock can break during removal. This is why ppl avoid this and d/c the lower rad hose instead.

Anyway, the only time you are sure you have 50% is a dry fill from factory.

When the car is serviced later on...it is always some guess work, approximation etc. The key things are:

1. You should know what you want in % for cold weather protection. Not sure? Err on the safe side and aim for 50%-60% no matter where you live in the US.
If you live in Vancouver BC and never drive to Calgary in the winter, enjoy the 40% and dim sum. If you live in Calgary, Quebec, MN blah blah blah you should aim for 55%-60%. If you live in North Pole, enjoy the bears lol (j/k).

2. Test the coolant strength a few months and some few thousands of miles after a flush. This way you have a more accurate reading.

As a reminder, this pic is from Prestone:
* 50% ---> -36C
* 70% ---> -64C

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20181202_102519.jpg.fcf7fc4f8e74ae48ba7344f9d357d599.jpg (205.99 KiB) Viewed 2965 times

[erikv11]

To reiterate, overall I think this post is useful. A top hose, cheater method can work fine for some users. But like anything, it is what it is.

... Anyway, the only time you are sure you have 50% is a dry fill from factory.
...

It must be emphasized that this point is wrong.

The widely used method I mentioned above will flush water throughout the block, the heater core which is always circulating on P2-P80 Volvos, the radiator. The whole system! You'll get to 100% water in there which means 0% coolant. If the final refill includes "exactly half capacity" of pure coolant and is topped up with pure water to "exactly full capacity" then you know exactly how much coolant is in there. The system has exactly a 50% mix, or 40%, 60%, whatever your target is.

How precise the "exactly half capacity" and "exactly full capacity" numbers are, is irrelevant here.

Yes, there is water left in the block when you pull the lower hose - it is expected to be and that's why you use the above method.

Agreed, never use 50-50 mix when you're trying to hit a known concentration. 50-50 is a gimmick product only useful for top-up between coolant changes. My recommendation is to never buy it.

My long term experiences with the engine drain nipple are actually pretty good: I've never had issues with this drain bolt, never had it seized, like having it available. Use a deep socket to quickly break it loose then switch to a ratcheting box wrench during use. I agree access is crappy in general but would categorize it as easy if you're under the car anyway, e.g. any time the car is on ramps or stands. Wear safety glasses, you'll be looking up. I use the engine drain bolt to drain a small amount from the system in a controlled way, for example when changing the thermostat. Put a short piece of clear tubing on the nipple so you can drain into a bucket. Turn the flow on/off with the box wrench until you've drained just the amount of coolant you want.