Easy Coolant Flush

nord

Veteran Member
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Mar 5, 2010
Location
Southern Tier NY
TDI
All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
After a new heater core on my '14 SE I decided I better check our '13 SEL. Sure enough... Orange instead of pink. Based on some of the lessons learned while working on my SE and my distaste (literally) for coolant because it seems to migrate everywhere, I decided to experiment. I wanted to work totally from the top side of the car and not disturb any of the main plumbing.

So... Facing the car and just to the right of the air intake is the main return hose to the radiator. Just above that and on the hose neck is a small rubber hose that goes directly to the coolant reservoir. Release the clamp and prepare to pull the small hose.

I found that our shop vac hose is almost an exact fit for the reservoir. Remove the cap, place the hose, and fire up the vacuum. Remove the small hose from the neck and plug it by holding your finger over it. The result will be a turbulent backwash within the reservoir. Sediment and contaminated coolant will be pulled out of the system.

Once the coolant had been removed, then it's distilled water time. Just add it back through the reservoir until liquid dribbles out the open hose fitting. Put the small hose back in place and run the engine a bit or take the car for a short drive. (Make sure the engine comes up to operating temp.) Repeat the vacuum operation. After about three repeats you'll see pure water coming out the hose fitting with no hint of coolant. (Don't forget to clean the residue out of the reservoir. I'll almost guarantee the internal reservoir will be coated with a skim of orange.)

Vacuum the system down one more time. Very little water will be left in the system once done. Add about a quart of straight new coolant followed by a 50/50 mix to the reservoir. The heavy 100% coolant will displace the remaining water forcing it out the hose fitting. It's easy to monitor. Though it will seem to take a rather long time the pure water will rather suddenly turn pink. Let it run for just a bit and bring the reservoir to full. Make sure the small hose is back in place and run the car up to operating temp. Very little "burping" (if any) will be needed.

Check the specific gravity of the coolant for temp protection. In my case the mix was perfect. 400 miles on the car immediately after the change yesterday. Coolant is bright pink and no need to add even though I did have a reserve with me.

Oh... No HOAT on my skin or clothing. No "funny" taste in my mouth and a shop vac about half full of used coolant. This I dumped into a pail for recycling. No "chunks", just worn out coolant with an orange cast.

Once I saw what the vacuum was doing to coolant in the reservoir I was pretty much sold on the effectiveness of the procedure. It's sort of amazing to watch. I'd suggest having about five gallons of distilled water on hand and you'll be able to see when things really begin to clean up. Tools needed? A vac and a pair of pliers. It's that easy.

Note: What you'll observe within the reservoir is almost violent as the vac does its work. Don't be alarmed. Do, though, be aware that the inside of the reservoir will become contaminated by an orange coating and need to be cleaned.

Hope this will help someone here in the future. Do it BEFORE you need a new heater core.
 

Skimax

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Mar 4, 2001
Location
White mts, NH
TDI
97 B4 variant(retired at 330K), 2000 B5 1.8T passat retired, 2013 SE (buyback5/17) 2015 SEL, 2015 E-Golf SEL sold March 2019, 2018 Volt LT and a 2007 PRHT MX5 for fun
If there is orange coating inside the reservoir it's inside the whole cooling system one could conclude. So wouldn't this method of flushing be improved by using a quality cooling system flush followed but flushing with distilled water? Just wondering.
thanks.
 

jrm

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Jul 24, 2013
Location
Oregon
TDI
2013 Passat SE with nav (totaled)
never thought of that, so your just putting the vacuum where the pressure cap screws in? Where is it getting air from? the tiny return line?
 

nord

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Joined
Mar 5, 2010
Location
Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
Actually you'll alternately plug and unplug the return rubber hose. (Finger works just fine.) Vacuum (as stated) is placed directly where the fill cap would normally reside. The open end on the radiator fitting flows enough air and you'll observe the turbidity within the reservoir change as you plug and unplug the hose. The inside of the reservoir under vacuum will remind you of some of those cyclonic vacuum cleaner ads. It's a pretty good show. You'll swear that someone put detergent in the system with all the suds and bubbles.

Whether you use a chemical cleaner or plain distilled water you can expect the reservoir to be fouled with contaminates when you finish. Carefully wash and clean it before you get to the point of adding new coolant.

As to whether to use a chemical cleaner, I chose not to. This based on not wishing to introduce a foreign substance into the system and the possible results. The second water flush yielded nothing but clean hot water... Very clean and very hot. Perhaps a chemical clean would have done better or perhaps not. In any case make sure you have a clean water flush before you fill with new coolant.

The beauty as I see it is that the fouled coolant can be removed while the engine is at operating temp without fear of burning oneself. The thermostat will be open and any fouling in suspension will not have a chance to settle out. The same can be said for the flushes. You'll be surprised at the amount of the orange fouling being pulled back and this is why I mentioned that a good reservoir cleaning will be in order.

Burping the system will be pretty much a non issue on the final fill. Expect to have to add very little coolant after your first run up to operating temp. Based on 400 miles immediately after the flush it appears that my results have been excellent. Nice pink fluid in the reservoir and the coolant level has remained in the safe zone.

As I mentioned previously, assuming this procedure works as it seems to have , then coolant recovery is almost 100%. There will be no HOAT baths or showers, no waiting time between flushes, and generally a painless and clean experience. Sort of like a topside oil change with no worries about hoses or clamps and no leaks or spilled fluids.
 
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jrm

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Jul 24, 2013
Location
Oregon
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2013 Passat SE with nav (totaled)
I did a running coolant swap, added coolant while having the return line routed into a bucket. I put in 2 gallons that way. Next swap I will try this method for sure :D
 

Rico567

Top Post Dawg
Joined
Jun 13, 2003
Location
Central IL
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2013 Passat TDI SEL Premium (Turned in 7/7/18)
Since I've got a 2013 Passat and also own a shop-vac, I think I'll try this. So did you just use the VW G12+ (++, +++, etc.) coolant, or buy a different brand?
 

nord

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Location
Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
All VW except the distilled water. That was from WallyWorld.:p
 

meerschm

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Apr 18, 2009
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Fairfax county VA
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2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
What is the capacity of the cooling system? for my 09 jetta, it runs just over 2 gallons, so that a bit over a gallon of G whatever is needed to be added to H20 to get a 50% mix.

just wondering how you figured a quart of full strength coolant is the correct amount.
 
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nord

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Location
Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
Some days a good guess is about as close as one could come. The mix isn't exactly rocket science as a percent one way or the other will make no appreciable difference.

Consider... Under the best of conditions we can only guess at the amount of liquid remaining in the system after any type of flush. Therefor we assume the quantity. Knowing that pure coolant is heavier than water it makes sense to introduce a quantity into the system as the first step in the refill. Be it a pint or a quart it is what it is.

The beauty here is that an incorrect guess isn't a problem. Too heavy on the coolant and you vacuum a bit out and add water. Too light and you do the opposite. Either way waste will be minimal. No nasty cleanup and it's so easy.
 

jrm

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Jul 24, 2013
Location
Oregon
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2013 Passat SE with nav (totaled)
when I mix my coolant I always mix it 55/45 just in case of those artic conditions- its rare for here but we did see -27F at my friends house in Redmond OR winter before last
 

r11

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Mar 6, 2012
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NJ
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2012 Passat TDI SE 6MT (BB'd), 2015 Passat TDI SE 6MT
Excellent stuff. Now we don't have any excuses not to do it :)

Those that don't have a shop vac due to lack of space etc - get one, use it for this procedure and place it by the curb to be adopted. $$$$avings and job dunnrite !!!
 

car0430a

Member
Joined
May 31, 2015
Location
Wisconsin
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15' Passat SE TDI 6M
Any suggestions on if this will work on a 15' with the ea288 motor.
I just remembered I had some coolant test strips in my garage and decided to test my coolant. Well the results do not look good as per the side of the bottle when you compare the colors it states to service the coolant. I tried taking a picture of the coolant in a jar outside it looks orange inside the garage it looks pink.
 
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meerschm

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Fairfax county VA
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2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
Only tricky part is that the 2015 EA288 has a couple coolant loops. so that it will take some VCDS manipulation to operate the coolant pumps.

probably start a religious war over this use, similar to the fuel filter question.

but the concept of pulling coolant from the bottle with a shopvac vs drain will probably work.

just keep in mind it will require several cycles.

You sure the coolant strips are good for VW coolant?
 

car0430a

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May 31, 2015
Location
Wisconsin
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15' Passat SE TDI 6M
No I'm not sure they are compatable with our coolant, and does not say which they are good for on the little slip of paper either I've used them pretty accurately before on Chyrsler spec HOAT coolant. Upon further investigation into the coolant question thread I did find my coolant pulled out of the resavavor does look more orange than new coolant. I'm coming up on my 30k oil change guess I will have to see what the stealership will get for a coolant flush.
 

jimbo1mcm

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Jan 5, 2015
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CT USA
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2015 SEL TDI PREMIUM Blue 2015 SEL TDI PREMIUM's Silver and Blue
Sure would be nice to have a video from the OP showing how it works.
 

nord

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Location
Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
In this case I really don't see the need for a video. Words work as well or better. Simply remove the small hose at the right upper (return) side of the radiator at the plastic neck. Plug the rubber hose because it runs directly to the coolant reservoir. Apply vacuum (shop vac) to where the filler cap on the reservoir would normally be and watch the action.

Cycle the vac on and off until not much coolant is being removed, then fill the system with distilled water. Some have suggested filling with distilled water and cleaning chemicals. You'll note that the system is mostly full when liquid begins to flow out the neck where the small hose was removed. Replace the hose and drive the car to bring it up to temp.

Repeat the purge cycles until you see clean water, then follow my instructions about filing with new coolant. And don't forget to clean the reservoir before you add the new coolant.
 

Rico567

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Jun 13, 2003
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Central IL
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2013 Passat TDI SEL Premium (Turned in 7/7/18)
No I'm not sure they are compatable with our coolant, and does not say which they are good for on the little slip of paper either I've used them pretty accurately before on Chyrsler spec HOAT coolant. <snip>
My understanding is that the coolant test involves measuring pH (the measurement of acid <—> base on a scale of 1-14), and that the trouble starts when the pH gets too low (acidic). That means that the test strips are just pH strips, and anything that measures the relevant range should work. The question is, what is the acceptable pH range?
 

r11

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Mar 6, 2012
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NJ
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2012 Passat TDI SE 6MT (BB'd), 2015 Passat TDI SE 6MT
Got me a jug of G13, will do the change ... sounds too ez not to !
 

arikinthecity

Member
Joined
Jun 16, 2013
Location
Bergen County NJ
TDI
2013 SE DSG with sunroof
A YouTube video would be perfect for this. Some of us are not experts on doing these things. A pic is worth a 1000 words and a video is about 100K.please make a video and post a link
 

251

TDI Owner/Operator
Joined
May 11, 2002
Location
NW IN
TDI
2015 Passat TDI SEL
nord - please post a picture or two showing which hoses you are talking about. Will help if you can add arrows and labels. Also include an image of your shop-vac nozzle to show the size of it in relation to where the hose was removed - have no idea if you have a small or big shop-vac and attachment sizes/types do vary a bit.

Please remember some of us are still learning about these cars and unlike you have not gone through the whole cooling system (know you have had more than your share of fussing with coolant-related issues) so we lack the experience and knowledge you possess. What seems obvious to you may not be so clear to others.

And I do thank you for posting your experiences here as it does help other owners perform maintenance tasks, find solutions to problems and/or learn more about our NMS Passats.
 

nord

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Joined
Mar 5, 2010
Location
Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
How about you just call me and I'll step you through the whole procedure? Truthfully I get the feeling that a number of you (with the best of intentions) are simply too anal and find it difficult to believe this procedure is so simple.

One small hose, a clamp, and a vacuum source which will more or less seal the cap area of the reservoir. That's all! Don't be afraid.

So... Bruce Miller (607) 358-7435 (EDT)
 

nord

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Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
Sorry - I'll summarize and clarify...

Reservoir - Any suction source that will allow vacuum to be applied to the reservoir.

Radiator hose as pictured. Remove the small rubber hose and follow my instructions in the other threads.

Rag? It highlights the hose area. Not necessary but good for soaking up minor coolant drips.
 

nord

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Southern Tier NY
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All turned back to VW. Now a 2017 Hundai Tuscon. Not a single squalk in 10k miles.
Because when you go to fill the system the open neck gives an excellent indication of fluid level and easily shows the transition between water and actual coolant.

This isn't to say that my way is the only way. It's just that I know what's simple and what works.
 
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