Changing radiator fluid

[wgriswold]

Recently a thread had good pictures of two petcocks to drain radiator fluid. One was behind the front bumper and drained the radiator and the other was in the back of the engine and drained the block. Today I was looking for these drains and it seems that I don't have them.

Can anyone help me find these petcocks or maybe they aren't there on a my '03?

If they don't exist what is the best way to drain the fluid?

[haoz129]

You have those petcocks for sure.
I have 2003 XC70 and I change coolant every two years.

Method 1:
Normally by using the petcock under the radiator you can have most of the fluid out. Then just fill and work air out by squeezing coolant hose. This is good enough.
This petcock/screw is under the radiator on the right side. You can find it through the hole on bottom of the front bumper.

Method 2:
The first time, I disconnected the big rubber coolant hose from the radiator then put my home made circulation system in between. Started the car and by using vehicle's water pump I got all the old anti-freeze out. At that time I was kind of perfectism. I didn't know the status of the coolant as I bought the car used. So I hate to have the old fluid even a drop.

Science & Fact:
- Coolant won't freeze even you don't change it often;
- Coolant has additive to protect the engine from rust. And additive will be consumed after time. By this means you need put new additives regularly (Volvo says 2 years) by replacing coolant.

Conclusion:
Although my circulation system worked very well I never use them again as I think the drain & fill works well enough. Drain & fill will provide enough additives to protect your engine.
I may only touch the other valve which is at rear of the engine block when I disconnect the turbo.

[wgriswold]

Thanks. I found the radiator drain. Somehow I got it in my head that it was behind the license plate in front. Now I will go back and look for the block drain. I found some good pics and will look again. I would like to get it all this time and then I agree with you, periodic on time drains of the radiator will suffice.

Thanks for the help.

[Astro14]

petcock on the rear of the engine is on the metal coolant line that runs just above the oil cooler. Start at the oil drain plug, go towards passenger side about 8" and then go up about 8"...

[wgriswold]

Thank you all for the help. I did see the drain on a metal line but was expecting it to be in the block and so dismissed that valve. Now off to the store for antifreeze.

[wgriswold]

Just finished with the fluid change. An easy job thanks to your help. Thanks.

I was surprised to get only four quarts out of the engine drain and only one quart from the radiator drain. Does anyone know what the system holds?

[Astro14]

Should be in the manual...from memory, I think it is 8 QTS...

[wgriswold]

I can't find it in the manual and on the Internet I see seven, eight and nine. In any event, five quarts is about 50%. Is that about what you get? The car was up on ramps and I wonder if that could have caused it not to drain properly.

I think I will wait a few weeks and then repeat the process. That will replace about 75% and I will call it good.

I wonder why someone doesn't make an additive that contains all the components of antifreeze that go bad and we could just add that.

[jmoser]

I just pop off one of the ~3/4" rubber hoses from the oil cooler, it drains a heck of a lot faster plus it is the lowest spot on the entire system so drains more.

My radiator has a slow leak [ probably at the tank crimp] so I am topping off constantly; still a good idea to drain once in a while to get any crud out of the system.