How to do coolant flush(distilled h2o) Buick lac?

[TmanP]

I was just wondering what the best way to change my coolant in my '06 Lacrosse is. I'm sticking with dexcool. I don't want to use tap water for the flushing, so I was thinking:

-buy 15-20 gallons of distilled water
-buy coolant

-keep doing drains and fills of the water until it runs clear, then filling with coolant

But I was just wondering about any tips anyone may have. The car has a radiator, of course, and an unpressurized expansion tank. It's not self bleeding, according to the manual, there's a bleed valve. How do I do this? I've never changed coolant before. Any explanations and tips are much appreciated. Any other things to note?

 

[doublebase]

It depends on the condition of the coolant in the vehicle right now...if it's dirty - dexcool can sometimes certainly leave a nasty residue that can clog heater cores, etc - then I'd flush it. If it's relatively clean and it's been changed before, I wouldn't worry about flushing it out, I'd just do a drain and fill, then maybe do it again a couple weeks from now. That should give it some time to kind of free up anything that's a little messy, then drain and replenish.

See, if the dexcool has kind of coagulated, running water through it really won't clean it out. You'll have to flush it out. I've literally had to disconnect heater core lines and flush hot water through them to free up blockages. I'm assuming your car isn't bad, so simple drain and fills spread out over time should replenish your coolant while cleaning out the normal debris that accumulates on the bottom of radiators (corrosion, rubber, dirt, etc). The little specs of stuff.



You could go through the trouble of running the car with distiller water, but then you'll have it trapped in your block and you'll never really know the right mixture of coolant to water (I mean I guess you could guesstimate and probably be fine). And if your just planning on pouring gallon after gallon of water through your radiator, it's a waste of time. They do sell actual "flush/cleaner" kits - but I'm not sure how much of a benefit those are either. Like I said, if it's really dirty, even a cleaner may not free it up. It probably isn't, so I'd just do a drain and fill and then repeat it again in a couple of weeks.

This is just my opinion...what I normally do. And I've never had an issue.

As for the bleeder valve, you just loosen it and wait for the coolant to flow out in a stream. Be careful because they are know to snap when you loosen them. If you try to loosen it and it won't loosen, I'd probably leave it alone.

 

[TmanP]

The dexcool may be original. It doesn't look great but not terrible.

 

[slacktide_bitog]

A modern GM care has a non-pressurized coolant tank?

The engine should be cold when you do it. Also, get the Lisle Coolant Funnel. It *really* helps!

Drain the coolant, then attach the Lisle funnel to the radiator cap. Fill the radiator with coolant and water. If you by the 50/50 premix, cool. But if you buy the concentrate, make sure you mix it with water *before* pouring it into the radiator. Don't just pour the full-strength coolant first then add water.

Fill it until the funnel is more than half full (the instructions it comes with will tell you just how high to fill).

Then, start your car and turn the heat to full blast. If you see the coolant level going down, add more coolant. You are done once the coolant stops bubbling and the level stops going down.

 

[TmanP]

How much coolant am I getting out by doing it this way? How many times would you do it if the coolant was potentially 11 years old?

 

[DP78]

Dex-cool is rated for use up to 100,000 miles. After that, it just doesn't protect as well.

Dex-cool got a bad rap initially because of the sludge. The sludge is a side effect of a leak. In other words, as the leak continues it will decrease the level in the system, obviously. As that happens it leaves behind deposits. What tends to happen is people will not notice or will continue to top off the system over a long period and it will continue to build up these deposits that eventually turn into the sludge. It can get really bad quick too.

For the most part, you can drain and fill like you want with no issues. I have one of those funnels that connects right to the full port that you can add around 2 quarts of fluid to. I would top it all off with the funnel and with the funnel still attached and car off crack the bleeder. Do this until you get only coolant. Finish filling the system. Cap it off and make sure to set the expansion tank level as well. Let it get nice and hot, watch the gauge for an overheat, once it gets hot shut it off and allow it to cool for around 15 minutes. As it cools it will push the air out and replace it with coolant. You can then check the level and do again if necessary.

 

[slacktide_bitog]

Originally Posted By: TmanP
How much coolant am I getting out by doing it this way?


As much as you'll need to get out

Quote:
How many times would you do it if the coolant was potentially 11 years old?


you only need to do it once

Remember, most people never change their coolant ever.

 

[Merkava_4]

Just do a drain and fill. One year from now, do another drain and fill. Each time you do a drain and fill, you change out 1-1/2 gallons of coolant.

Open the bleeder on the thermostat housing before you pour in the new coolant mixture. When you start to see coolant coming out of the bleeder, close the bleeder. That's how you get the air out.

Clean your reservoir tank out.

 

[CharlieBauer]

Watch this video. I don't think you'll need anywhere near 15-20 gallons of distilled water.

 

[doublebase]

Originally Posted By: TmanP
The dexcool may be original. It doesn't look great but not terrible.


Alright, if it doesn't look terrible I'd just do a simple drain and refill. Just open the drain on the bottom of the radiator, remove the cap, get as much out as it allows...then refill with your 50/50 mixture of coolant and distilled water (and it's good you're using distilled rather than tap).

There literally is a 100 different ways and techniques to do this job...some people are want it all out - they drain the block, flush the whole thing, and replenish. Some people like to take it to a shop and have them use a machine that exchanges all the fluid...I've used those machines and they do get all the fluid out. But honestly if you just do simple drain and fills every year you'll be fine. A lot of people do this...and so do a lot of dealers. It's easy, it's quick, and if you keep up with it you'll always have fresh coolant.

Another thing to consider is that you may be on your original water pump, thermostat, and hoses. At 140,000 miles that's the time when that water pump could fail - if it hasn't already - and its a good idea to replace the hoses and thermostat at this mileage anyway. If you don't plan on doing this - and you go through the trouble of replacing all your coolant - guess what very well could happen? Your water pump will need replacing and you'll lose all that coolant you went through the trouble replacing. But at least at that point you'll have the cleanest cooling system in the world

 

[Kira]

Go back a few posts to slacktide_bitog; "...a modern GM vehicle WITHOUT a pressurized cooling system?

Do you know FOR SURE what you're seeing?
Dex-Cool systems REQUIRE air tight systems. Many have reported here that air is what causes the creation (precipitation) of "Dex-sludge".

Double check the cap on the coolant reservoir/pressure bottle. Is there even a radiator cap?

Cheers, Kira

 

[barkingspider]

I would do drain and refills w distilled until water is clear. Fill with concentrate coolant (half the capacity of the cooling system) then top off w distilled. Open bleeder til all air is out. Call it a day. That's what I did in my 06 escalade. Ur call on replacing hoses, stats, water pump. Then u won't have to replace coolant for another 100K miles.

 

[SteveSRT8]

Wow! Be careful here fellas.

We own several late model GM trucks. The service vans have an open recovery tank vented to atmosphere. The pickups have pressurized coolant recovery tanks. Both are FF with Dexcool, and we don't have any issues at all. All are run until component failure, usually in excess of 200k with no flushes or service to the cooling system.

And if you follow the slacktide's advice on almost any recent V8 from GM you may blow a head gasket or worse. These are reverse flow systems and MUST be refilled through the upper radiator hose.

 

[Kira]

"...These are reverse flow systems and MUST be refilled through the upper radiator hose."

Is this kind of system becoming the norm? Sounds like a mine field.

Filling through a disconnected hose sounds messy. Kira

 

[chrly919]

I bought a 2001 Corvette two years ago with 68,000 miles on it. This car has an LS1 with reverse flow cooling.The dexcool in the pressure tank smelled a little funky and looked like there was some deposits around the filler. Because of what I had found thru search on BITOG I just did a drain and refil. Smell and deposits went away and everything's fine at 99,000 miles.

 

[TmanP]

There's a radiator cap and an expansion tank. But that isn't pressurized.

 

[Gasbuggy]

Drain it, fill with water. Run it, drain it, refill with water. Run it, drain it, fill with concentrate. The leftover water will balance out the mix.

Or drain the old coolant and just refill with 50/50. This is good enough IMO.

 

[Virtuoso]

Originally Posted By: Gasbuggy
Or drain the old coolant and just refill with 50/50. This is good enough IMO.


If everything is working fine, this is all I would do as well. Don't fix what isn't broken.