norcoastal

I'm replacing a leaky radiator and I'm just running pure tap water now because it's leaking out anyway.

When I pull the radiator it will all leak out (I think). Tell me if this is a dumb idea, I was going to start it for a few seconds to flush all the water out. Is that dumb???

My main question is, do I run 100% coolant or a 50/50 coolant distiller water mix?

Ok two more questions, what coolant do I buy and what's the capacity of the cooling system? In other words, how much coolant do I need to buy?

logray

edit: since you've been adding tap water (do you know how much?) and don't know the mixture (you can use a cheap coolant hydrometer to test) I would recommend draining the entire system and refilling properly with proper coolant to DISTILLED water ratio.

50% coolant 50% distilled water pretty much always unless this is a track car, in which case you want to run nearly 100% distilled water plus a water additive such as water wetter/etc. Never run or add 100% coolant unless you are positive of the mixture ahead of time (example from a simple hydrometer test you know it is 25% anti freeze so adding 1/6ths the system capacity of 100% anti freeze would not put you over the recommended 50/50 ratio).

Stick with Porsche anti freeze or at least go to the VW dealer and buy G12 !!!!!!

The entire system holds just over 6 gallons (about 22 liters). If you are just replacing a radiator buying one gallon of anti freeze and another gallon of distilled water should be more than enough (pre mix them before you add it back in), and then you can pour the spare mixture back into the anti freeze container for later.

When you pull out the radiator you'll only collect about 1-2 gallons at most. It is not dumb to just remove the radiator, but do be prepared for a lot of fluid to come rushing out, wear proper protection and have large buckets ready to collect the fluid. Anti freeze is very hazardous.

It is recommended to refill the system using a vacuum fill system, such as the uview 55000. But it is possible to do manually by following the procedures to use the bleed valve and specific RPMs for certain durations. Loren has a write up on how to do the manual procedure over on renntech.org under the DIY for adding a third radiator for the 996, or if you have a copy of the workshop manual.

Unless you intend to remove ALL of the fluid from the car (major pain in the butt), ONLY use Porsche anti freeze or compatible as ANYTHING else will gel up and cause major problems in a short amount of time.

norcoastal

Thanks, that's good advice. I have no idea how much water I've been adding. Maybe 2 gallons over a few months??? think I'm going to replace the radiator and drive it to my mechanic and have him flush the entire system properly and add 50% distiller water and 50% G12.

Thank you.

logray

Fantastic idea!....

Not sure how far the drive is to your mechanic, but...

You are going to want to try to add back whatever you took out so you can safely get the car to the mechanic. If it is some distance away (longer than it takes for the car to warm up... you don't want to drive around without making sure there is enough water in the system)

To do this you'll need to start the COLD engine with the bleed valve up, coolant reservoir cap OFF. Let it run for 10-15 seconds or so, and with the engine running as the level in the overflow tank goes down (or as soon as it starts to go down) add more water until it doesn't take any more and stays at the max level. Then close up the rad cap, and leave the bleeder valve open. Drive the car around until it warms up, and do a few blips of RPM higher than 5k. Drive back home and let it FULLY cool down. Remove the coolant cap again once the car is cool and add more until it gets to the max line.

Then take it to your shop and have them properly remove all the old water/coolant mix and replace with new!

norcoastal

I really appreciate the advice, thanks again!

Macster

Run whatever ratio of distilled water/Porsche anti-freeze that provides your car's engine with protection against freezing in your area. (Note too that my info is the anti-freeze also provides some lubrication to the water pump seals.)

Generally a 50/50 mix of anti-freeze/distilled water (called out in the factory manual) is about right, though in really cold climes a slightly different mix of water/anti-freeze may be called for. IIRC this is covered in the owners manual. This along with the cooling system's capacity which should help you determine how many gallons/liters of anti-freeze and distilled water to buy.

I would not try to use the old coolant and bring it up to spec with new due to the amount of tap water you have used.

If you can ensure you remove all the 'old' coolant and its content of tap water just refilling the system with fresh anti-freeze/distilled water is ok. IOWs, there is no need to flush the system. You can of course, and if you want fill it with distilled water and run the engine a bit until the T-stat opens then let the engine cool and drain the water and dispose of it properly. But this is overkill. But you must be sure you drain all the old coolant out. There's the radiators and their hoses and the engine. There's a drain under the engine that I think with the reservior cap open will let all the coolant drain out the drain hole.

(Once the old coolant stops running out the drain hole, pour a gallon of distilled water into the reservior and see what it looks like. If colored with coolant then a flushing might be necessary.)

But unless the above happens, there is not enough residual fluid in the system with tap water in it to really affect the new coolant.

Be more concerned about when you refill the system getting all the air pockets out of the cooling system. The best way to refill the system is to use a vacuum system to draw a vacuum on the cooling system -- the hoses will collapse -- then turn off the line to the vacuum pump and open the line to a reservior -- vented to atmosphere -- of properly mixed coolant and let Mother Nature refill your car's cooling system sans any air pockets.

Sincerely,

Macster.

chsu74

You can buy distilled water by the gallon at your local CVS or any other drug store. I paid $1.30 or $1.60 per gallon about a month ago.

speed rII

And 50/50 mixture will give the maximum protection against the freezing.
Roughly -35c celsius (-31F)Should be enough if you arent living in antarctica

If freezing is not a problem, I would go with water and waterwetter.
Plain water won't protect from corrosion.

logray

The drain in the engine (coolant guide housing) will only drain a few gallons out at most.

The other 4 or so gallons of fluid lives in the miles of hoses, heater core loop, bleeder loop, radiators themselves, oil cooler, (some even stays deep within in the engine).

Along with the drain plug, you have to remove or disconnect at least 10 or so hoses to get close to the 6 gallons the car holds.

To get at the remaining gallon or so you can a.) use a vacuum tool such as the uview 55000 to repeatedly draw coolant from the nooks and crannies towards the engine block and b.) with all of the radiator coolant hoses disconnected at the radiators, attach the very clean low powered (4-5hp) shop vac blow side with duct tape to the large hard lines at the L/R top of the engine bay, and blow the coolant out through the lines in the front of the car. One will blow the coolant out the top of the radiator on one side and the other hard line will blow out the bottom on the other side. You can also detach the large bleeder hose at the rear of the coolant expansion tank and attach the vac to it, provided the bleeder hoses at the top of the radiator are disconnected. A similar reverse shop vac treatment to the heater core loop is permissible.

Oh... and gravity helps too!. When the car is level you won't get as much out versus having the front or rear of the car jacked higher than the other.

I've had thoughts about removing one of the hoses at the end of the loop furthest from the H20 pump and starting the cold engine and letting the pump do the work of excavating the system, but this was a very redneck thought that I immediately discarded due to it's absurdity.

medtech

FWIW, coolant is NOT an efficient heat transfer fluid. Pure water transfers heat better. The additive is only there to prevent the water freezing and cracking your radiator.

logray

...and prevent expanding frozen water from cracking the engine block. I'm not so sure I would rely on frost plugs alone to do their job.

Reminds me of when I was in Fairbanks a while back. When it is -40 below, either you leave you car running in the parking lot (and unlocked) during errands or plug it in or... ooops!