Is there an easy way to do a coolant flush and should I do it?

Ealerguy · Oct 8, 2013

For the coolant flush can I just open the drain on the bottom of the radiator, run the car at idle till it opens the therm. and then run a garden hose to the overflow tank till it runs clear then replace the fluids with coolant?

Anyways my car is a 2001 jetta and has 300+k miles and has never had a coolant flush. My CTS is bad so I have to replace it. Should I do a coolant flush while I'm at it?

noxneon · Oct 9, 2013

run the car without a termostat. that will just open circulate whatever is in there. then flush it a couple times, and when your satisfied with how clear the water is, add coolant and finish up.

Corsair · Oct 9, 2013

my 0.02-
(assuming that you aren't trying to address any particular problem such as no cabin heat, overheating, etc....)
I wouldn't be concerned so much about the "flush"- I personally wouldn't connect a garden hose and its associated "earth water" (with minerals etc.). Just drain the coolant and refill with a proper ratio of correct VW coolant and distilled water. Since the car hasn't had coolant maintenance, maybe consider driving it for a few days with the new coolant, then doing the same process again.

LNXGUY · Oct 9, 2013

I wouldn't bother. I'd just replace the coolant the next time the TB is due.

Ealerguy · Oct 9, 2013

Thanks guys!

I'll just drain what I can with the drain plug and removing the CTS. Then fill her back up.

Drewmeister · Oct 9, 2013

Also disconnect the oil cooler hoses -- I got another couple quarts out after doing so (radiator was already drained). See http://www.myturbodiesel.com/1000q/a4/coolant-flush-TDI.htm for pictures.

I wouldn't bother with a flush unless you drain a lot of rust/other particulates with the old coolant or find something else nasty.

Lensdude_com · Oct 11, 2013

300K miles on the factory water pump? They are usually changed out with a timing belt job and lots of coolant has to be replaced after a new water pump.

Ealerguy · Oct 11, 2013

When we got the car back (we loaned it to someone) it was time for a timing belt change. Me being dumb I found the cheapest dealership to do it. I'm sure they had to replace the fluids. But my CTS went bad and my thermostat is bad also. So I figured I should run some coolant flush additive and flush/drain her then refill.

burpod · Oct 11, 2013

hopefully your car won't go boom after a botched dealer TB job o.0

Ealerguy · Oct 11, 2013

It's almost time for another TB change and I'm not sure if I can really pull it off.
BTW is coolant flush additive a good thing or a bad?

Ealerguy · Oct 11, 2013

Also what is the longest you can go on one TB?

Lensdude_com · Oct 11, 2013

Ealerguy said:
Also what is the longest you can go on one TB?

Timing belt life isn't something you want to test but 75K miles is the longest I will go before replacement.

Ealerguy · Oct 11, 2013

Bump on coolant flush additives? I'm hoping to do a drain tomorrow. It says to let the additive run in the coolant for about 10min before flushing. Are these additives good or bad?

Lensdude_com · Oct 11, 2013

I would be reluctant to use any type of flushing additive unless it was advertised to be compatible with G12/13 coolant.
So what's the name of your cooling system flush additive?

mk3 · Oct 11, 2013

You should have plenty of distilled water on hand or readily available. I have never heard of flush compounds being incompatible with coolants - of course that is no guarantee but just saying it has never come up and I've been around the forums a bunch. I wouldn't call them additives because you don't leave them in there permanently.

What I have usually done when I encounter a car with deferred maintenance is to do several rounds of fill and drain with distilled water. after the last drain add the coolant to get to 50% of _total_ capacity and then continue with distilled water.

The flush additive might not be necessary as others have said though I have used them in my past.

Ealerguy · Oct 11, 2013

It's called "Solder Seal GUNK 10 minute radiator flush". Removes grease and scum plus rust and scale.

Ealerguy · Oct 11, 2013

They also sell a anti rust and water pump lube. But I didn't buy it. Any ideas if it's good or bad too?

Lensdude_com · Oct 11, 2013

I would only do a cooling system flush/rinse if it was necessary to use lake water in an emergency to get my car home after it overheated out in the boonies. I would want to remove any organic matter or dissolved solids before refilling with a 50/50 mix of G13 coolant.

Ealerguy · Oct 11, 2013

Okay thanks guys! I think ill just put the flush "additive" in, drive for 10 min, let her cool. Open the radiator drain, maybe pull the hose off the oil cooler. Let her drain. Then fill her back up with coolant. This is all of course if the coolant doesn't show any bad symptoms.

AndyBees · Oct 11, 2013

My 2000 Jetta has approximately 50% of the Original coolant in it........... I cannot imagine flushing the coolant system or installing any flush stuff!

As Lensdude stated, unless I have to use some roadside stream water in an emergency, I'll never flush the coolant system.

Changing a TB 25% early is a waste of resources. I've seen plenty of them with well over 100k miles! The internval for the long-life belt is 100k miles. Start looking for your window of opportunity at about 95k miles and try to get it done no later than 105k miles...... has worked quite well for me!

I changed out one back in June or July with the OE TB at 149k miles on it, 03 Jetta! One of my friends is driving an 01 with about 125k miles on the TB ...... I changed it back in November of '08, so I know the miles are correct!

Ealerguy · Oct 11, 2013

So no additive just a drain and fill her back up?

Ealerguy · Oct 11, 2013

Don't forget that my CTS and thermostat have both quit working for some reason. That's why I'm doing this in the first place.

Lensdude_com · Oct 11, 2013

Ealerguy said:
Don't forget that my CTS and thermostat have both quit working for some reason. That's why I'm doing this in the first place.

they quit working because they are really really old

Ealerguy · Oct 11, 2013

Good call!

AndyBees · Oct 11, 2013

Flushing the coolant system would probably be a good idea if rust appears to be in it and/or settling in the expansion tank. If that be the case, at some point in the engine's history, someone was using basically staight water, thus the rust!

Otherwise, there is no reason to be flushing the coolant system..

The Temp sensor and T-stat do wear out as indicated by Lensdude!

Ealerguy · Oct 12, 2013

Jobs done! I replace the CTS and thermostat in about an hour. Only had to replace 1 gallon of coolant and the coolant looked good.

Thanks for all the info guys!

Lensdude_com · Oct 12, 2013

Congrats!
Should have also mentioned to check your antifreeze strength before replacing lost coolant to make sure the Specific Gravity shows at least a 50/50 mix of G12 and distilled water.

Is there an easy way to do a coolant flush and should I do it?

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