Coolant flush

[mecheng]

Good to see him around still I thought coolant is running through the heater core no matter what the temp dial is set to?

[abscate]

Yes, heater core is constant full flow on these cars, Straight off cylinder head.

Closed thermostat bypasses radiator

[mecheng]

Yes, heater core is constant full flow on these cars, Straight off cylinder head.

Closed thermostat bypasses radiator

That’s what I remembered. He has in his video to
Set the Temp dial to heat. I think that is the old
School system where you are moving a valve for the heater core

[abscate]

I think the older Volvos you had to do this. Modern cars still have flow controlled heater cores, like my E83

[mecheng]

It’s not a bad thing. The heater core Acts like a mini radiator

[C1ph3r]

I wanted to re-open this topic. I am doing a full coolant flush and clean with liqui moly coolant flush on my 99 V70 T5. I have done many coolant flushes but this is my first Volvo.

Here is how I am currently doing it
Removed thermostat, drained coolant, topped off with distilled water. run motor. drain. topped off, run motor and repeating until water comes out clear. This is using a lot of water.

I would like to actually run the motor while pouring in fresh water to flush it out faster like in Roberts video. But...

From the flow diagrams I have seen, the water goes into the top of the rad, then flows to the bottom of the rad, and out the bottom hose to the block, through the motor and then back into the top of the rad.

If you were to run the motor and fill with water to flush, it seems to me that you are essentially only flushing clean water through the radiator and not the motor as the water will drain out the petcock at the bottom of the rad before it gets a chance to circulate through the entire system.

If I misunderstood that flow diagram, then the opposite would be true. You would flush out the block but would never actually get water to flush out the rad.

I am trying to get as much out of the old out as well as the cleaning agent before i put in the new stuff. Am I over thinking it? I tend to be doing that with this car. Seems my almost 30 years of tinkering with cars went out the window with this one. I am more paranoid (thanks to the internet) about how and what I do to this car than any other vehicle I have ever had. Thanks everyone.

[abscate]

It takes about 15 minutes to completely flush. I just idle it with a hose going into the reservoir, pet cock open, so that I have flow out of th e radiator Down low as well as out of the top,of the reservoir.

Don’t walk away or talk on the phone, if the hose slips out, you destroy your engine

If you want to run distilled, pour two gallons of distilled into the reservoir to flush out most of the tap,water.

[C1ph3r]

It takes about 15 minutes to completely flush. I just idle it with a hose going into the reservoir, pet cock open, so that I have flow out of th e radiator Down low as well as out of the top,of the reservoir.

Don’t walk away or talk on the phone, if the hose slips out, you destroy your engine

If you want to run distilled, pour two gallons of distilled into the reservoir to flush out most of the tap,water.

thanks abscate. I have read TONS of your posts and learned a lot from you. glad you responded.

that was my thought but will it flow through the entire system that way? seems that it would either miss the motor or the radiator since its just running out the bottom before it can flow into the other areas down stream from the petcock. our city water is garbage so i will for sure keep using distilled.

[abscate]

I have stood on the shoulders of many here.

You can flush with the petcock closed so you know the water is going through. You can loosen the lower rad hose clamp and periodically dump it too, it won’t be too hot.

It’s not rocket science , or all Volvos would be on Saturn getting a ring job

[C1ph3r]

i think whats got me all in my head the most is that i used that coolant flush stuff. now I'm all paranoid that i get it all out.