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Discussion Starter · #1 · (Edited)
This is one of the best things that you can do for your car.

Flushing out the old and renewing is a good thing.

First lets get the old out and flush the thing.

Take off the Thermostat housing. (on power steering equipped cars you have to remove the power steering bracket/mount)
Remove the 5 13mm Bolts that hold the Power Steering Bracket to the Power Steering Pump, and Block







Bracket removed so you can see the 5 bolt holes.




Remove the lower hose at the t-housing. (first douching.)





Remove the 2 10mm bolts use a 10mm 6pt socket be gentle (a cordless impact works great.). Spray with
CRC Freeze-Off, and let it work, then Spray it on again and lightly tap the socket on the heads of the bolts.




Pry the t-stat out. (Second douching).



Clean the bolts and coat with never-seize

Replace the cover of the t-stat housing with the old o-ring (leave t-stat out). Tighten the bolts (DO NOT HONK).

Replace the lower hose on the cover of the t-stat-housing and tighten.

Loosen the upper radiator hose and fill the system from the top with water and 1 cup of CLR. Re tighten the hose




Fill the res jug to the middle mark.

Turn the heater on Full HOT.

Start the car, and let it run (You want the car to circulate the water /flush for about 10 minutes.....

Allow to cool, then Take the lower hose off and allow to drain (This will be ugly and acidic take precautions and avoid the water out of the eyes and skin flush with water if you get it on you.).

Now replace the hose and re-tighten.

Take off the upper hose and refill with water, this time with 1/4 cup of baking soda.

Re tighten the hose.

Fill the jug

Start the car and allow to circulate for 10 minutes (watch for leaks.).

Allow to cool.

Remove the lower hose and drain.......

Re tighten the hose.


Now using a garden hose and pressure, force the nozzle on the upper hose Into the radiator opening.
Allow the water to "bubble" out the head flange assembly. Run till clear...

Reverse the hose and run it to the block so that it will "bubble" out the radiator upper connection.

Reverse and do it again till clear....







Drain the system by removing the lower hose and t-stat cover.

Replace all your hoses.

But wait theres more.......

Remove your two heater core hoses at the heater-valve and the hard line.

Now run water with the hose in the upper hose, and allow it to drain out the bottom till clear,
then place the hose in the bottom and allow it to come out the top till clear, do this a couple of times.

Reconnect the hoses.

Drill a 1/8 or 1/16 inch hole in the lip of the replacement thermostat.



Insert it then the "new" o-ring with the cover, use only a 10mm 6pt 1/4 in drive socket and DO NOT HONK, snug it up, it only takes 17 inch pounds of torque..

Now fill your radiator with 50/50 blend through the upper radiator hose,
(and it is cheaper to buy full strength and cut it your self than buying the pre-mixed crapola.)
till it "trickles out the radiator, then reconnect the hose, and tighten it, then fill the res......
Start your car and check for leaks.

Should be good to go for a few years.

Notice I say to flush the system with your old hoses, as the
CLR may deteriorate the hoses a tad, so do that to your old ones.
Be sure to include the hose that comes off the drivers side of the head to the hard line.

I haven't had any issues with CLR and Hoses, but I do replace all the hoses about every 5 years, after I
have owned the car as on Day 1 I replace them all.
 
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Very good diy!

Because the sytem is now fully flushed and cleaned would you recommend using a modern VW coolant such as G12 plus or G12 plus plus? This stuff is much better in engines with mixed metals and will last a lot longer than regular coolant. The downside to G12 is that you MUST NEVER mix with anything other than itself or water.
 

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Discussion Starter · #3 ·
Ya know I have been using the older green stuff for years, and never had a systemic failure, but then again I usually flush it out every couple of years... I don't have an aversion to the pink stuff but I have only one car that requires it. Since you have flushed all the green out, you can go with the Pink and be sure that no cross contamination will occur.
 

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Discussion Starter · #4 ·
updated with pictures
 

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Discussion Starter · #6 · (Edited)
Depends, if you have it the hose loose on the radiator then it trickles out the water outlet flange on the block.
If you have it loose on the water outlet flange then the water trickles out the radiator.

If you look at the picture, I am "hosing" to the engine block, and you can see below it that there is water coming out of the radiator...

Filling it is the same, you fill it via the upper radiator hose, and it will "trickle" out of the water outlet flange. Placing the "hole" in the t-stat prevents a air bubble from being trapped. As the old way to fill it to prevent a 'bubble" was half via the radiator, and half via the engine water outlet.

 

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i have all new hoses, new heater core, new expansion tank, new engine, but a radiator that ran 1000 miles with a really rusted engine, a really rusted metallic coolant pipe, and a really rusted heater core. i did the whole flush process until it ran clear before installing a new radiator 1000 miles ago, but there is still a light deposit of rust and engine oil in my 1000 mile old radiator. is there a good product and method to flush it with while its out of the car?
 

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Discussion Starter · #8 ·
You can use a commercial coolant flush, but you have to remove all your coolant and refill with water prior to running the flush usually. Read the instructions.... I have used CLR to flush a badly corroded system before. I usually never have had oil in it tho, and don't know how well it works for that.
 

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I realize this thread is 2 years old. I see you had a thread on replacing the water pump as well HERE.
Did you flush your system with the old pump on the car?
Were you having over heating issues?
 

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Discussion Starter · #10 ·
I flush my system when ever I usually change a t-stat, that is about every 2 years. I replaced the water pump because it was original, and leaking at the front shaft seal.
Just because a thread is aged don't mean it isn't good. I write these how to's so that folks can get an idea on how to do things themselves and not take it in the rear at a dealer/shop if they are going to have it done.
While these were writing for a 90ish Cabriolet, they are a good example of how to do it on a mk1 in general.

For example, there are 3 different ways to mount an a/c unit. The way I show here, there is the way the Sanden compressor is mounted on a rabbit diesel, Low and under neath. Then there is the "YORK" style of compressor that was a dealer add-on on the Cabriolets, as well as more a "Gasser" style of Rabbit as the a/c on a Diesel was mounted on the engine in Germany as part of the assembly, and shipped over to the states.
 

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Good to know. I will be relying on your advice while I get my wifes 1983 Rabbit Convertable to the reliable state.
MNBen
 

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Do you have a recommendation for temp setting and brand on a replacement thermostat? I have the 1983 1.7L engine. It only gets driven in the summer.
I see you recommend on drilling a small hole in the thermostat.

MN Ben
 

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Discussion Starter · #13 ·
the stock is sufficient for all purposes, unless you live in the desert in the summer....the hole is to allow air to pass the t-stat so you don't get the magic air bubble.
 

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Discussion Starter · #15 ·
You can as the system is drained, but you are better served by breaking those connections and flushing and back flushing the heater core that way separately.
 

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True. This I understand, but I purchased a new upper, lower, and bypass hose (they were feeling a bit soft). You said that you put in new coolant system hoses, but does this typically include the hoses to your heater core? They are not feeling as soft as the others but I was just wondering if changing them if recommended.

J
 

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Discussion Starter · #17 ·
It depends on if I have replaced them. They are a little painful to remove as you have to remove the cover 3 phillips screws one that can hide, and then remove the hoses before you can really remove the cover.

So if you want to, then go ahead while you have it all cleaned out. With the fluid all drained then there shouldn't be too much spillage, and you don't need to use hose pinch pliers to keep the rest of the cooling system from running out of the two hoses....
 

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Braino.... What if you know is affect of CLR on rubbler water pump impeller. I may just change out pump but I have to flush system there was corrosion inside block when I pulled pump off. pump felt tight and wasnt leaking just thought while it was apart and the headache it would save for the price.
 

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Discussion Starter · #19 ·
CLR is a corrosive, I use it for the heater cores, but it is no different than other acids. That is after you run it in your car for a few minutes and drain it, then you need to re-fill your system with water and a box of baking soda to neutralize the acids. You run this for a bit and drain it.... then you run clear water through the system again. To be honest I use a engine flush for the block and save the CLR for heater cores.... I do then follow it up with Baking soda to neutralize the CLR but as I am doing the core it is limited to only the core and the 2 hoses.

About every 2-3 years I tend to flush the block and radiator, or if I have a major change ie: radiator water pump... I want to ensure that I have a clean system.

Dubs are a little different that it is a "closed" system.
 
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