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View Full Version : What is the proper way of flushing the Cooling System?



mx54life
10-14-2015, 02:27 PM
I am so confused with different info I read on how to flush the cooling system. Engine running or not running? Tap water or distilled water? How do you flush your system?

Also is 50/50 mix not good for our car?

Thanks in advance.

revlimiter
10-14-2015, 02:50 PM
Always use distilled water, no matter what procedure anyone gives you or what you happen to read. Anything that involves screwing a hose into an adapter in your rad hose should be avoided.

Demon I Am
10-14-2015, 02:52 PM
I usually drain the radiator
Replace the thermostat (it's cheap, so why not)
Drain the reservoir
Fill with distilled,
Run the engine for 5 minutes or so (short drive around the hood). You want the fans to come on to recirculate the coolant out of the engine block.
Let cool down, unless you like living on the edge.
Drain and refill with distilled.
Repeat process until what's coming out looks like mostly water (debris chunks indicate deterioration in your cooling system.
Drain the radiator one last time and then fill with 50/50 mix.
At this point it may be helpful to drive the car up on ramps, or at least try to get the radiator elevated a little.
run the car with the radiator cap off. This is to help remove any air that might be in the system. as the radiator drains down, keep topping it up.
with a gloved hand, give the upper hose a few squeezes to make sure there is no air trapped.

Once you are satisfied, and the radiator is no longer draining down fluid, turn the car off, install the radiator cap, and fill the reservoir to the minimum line. Check the reservoir level after your first drive, and top off to the maximum line, whole the car is still hot.

Greasemonkey2000
10-14-2015, 03:25 PM
As already stated ALWAYS use distilled water to fill. Personally i have no issue with using tap to flush because if you use a hose you can create a decent amount of pressure(typically 30-80psi) to assist with flushing but then I'd run a gallon or so of distilled thru it.

As far as mixture this really depends on climate and usage. Coolant is suppose to keep the water from freezing and assist with temp stabilization of the water. I personally did approximately 60/40 mixture water to coolant since it rarely sees freezing temps and have more warm/hot months than not. I also used a bottle of Redline Water Wetter. :drinkto:

revlimiter
10-14-2015, 03:42 PM
The problem with using tap water to flush is that it stays in your system. Some of the flush water stays in there no matter what you do.

Water Wetter should be used by itself with straight water. You're not supposed to add it to a system with antifreeze.

Demon I Am
10-14-2015, 04:12 PM
Water wetter is great if you live somewhere that it won't freeze up. I used to run it in the summer, then flush in the late fall.

kung fu jesus
10-14-2015, 04:22 PM
If you are doing a flush, replace ALL the coolant hoses. Some engines have drain plugs down low on the blocks. I know some 1.6 engines do, not sure about the rest.

Greasemonkey2000
10-14-2015, 04:53 PM
Well not sure about all/other coolant additives but the Redline Water Wetter is indeed compatible with antifreeze:
http://www.redlineoil.com/Products.aspx?pcid=10
"-Reduces or eliminates bubbles or vapor barrier that form on hot metal surfaces to reduce coolant temperatures by up to 20°
-Superior heat transfer properties compared to glycol-based antifreeze
-Compatible with new or used antifreeze (including DEX-COOL and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems
-Improves heat transfer and reduces cylinder head temperature"

mx54life
10-14-2015, 07:00 PM
Thanks a lot again guys. So to simplify the process should be......

1. Drain coolant.
2. Replace all old coolant hoses.
3. Remove old thermostat.
4. Close the cooling system circuit and fill with distilled water and run engine (w/out thermostat) till warm.
5. Drain the distilled water and repeat #4 at least 3 times or till distilled water is clear.
6. Replace Thermostat and fill with coolant mix (add additives as desired).
7. Jack the front end up and run the engine with radiator cap off and to rid the system of air.
8. Top off rad and reservoir, cap on and done.

Question.....is it worth it to add coolant additives if the engine is boosted?

Slipstreem
10-14-2015, 07:47 PM
https://www.youtube.com/watch?v=s--5ft5YiHg

This a good video. It pretty much goes through what Demon said. I've never owned a boosted car but, my dad uses water wetter for his Stealth TT. He says it works great.

Greasemonkey2000
10-14-2015, 07:53 PM
I started looking into Water Wetter after hearing the military used it in all their combat vehicles. I read ALLOFIT(more or less) about the subject and really no downside but in all honesty I'm not one willing to make a decision based on one source of information so I'd say read up. :drinkto:

revlimiter
10-14-2015, 08:28 PM
I've used it several seasons. Water wetter is great at de-gunking your cooling system. All of the gunk finds its way into your overflow bottle and you start to question if you have a blown head gasket. In 9 out of 10 cases, it's just water wetter making everything yucky. All of my autocross buddies who tried it the same time I did had the same results.

If your cooling system is super clean, use water wetter.

If you have a dedicated track car, use water wetter.

If you like flushing your cooling system often, use water wetter.

Otherwise, a good radiator, reroute, proper rad ducting, and 70/30 will more than do the job. Honestly, I'm not trying to rain on any parades. It's just not the best thing for a street car IMHO.

mx54life
10-14-2015, 11:04 PM
Yup she is a street car. I would love to do autocross eventually but won't really be that much either. I do have a Mishimoto rad, reroute, tho' I need to look into proper ducting and add more distilled water on my premixed 50/50 to make 70/30 (hopefully this is acceptable). Now I am more confident to start this flushing business tomorrow. Thank you boys.

HarryB
10-15-2015, 03:35 AM
Useful info gathered all together, thanks! Will be doing mine soon(ish) accompanied by a lower temp thermostat (72 deg. C), ao it is nice to have a confirmation on the process! Bookmarked!

Greasemonkey2000
10-15-2015, 09:59 AM
HarryB: Might want to look more into the use of a lower temp thermostat with a factory ecu. In short what i found, after even buying a lower temp thermostat, is that the 195*F oem thermostat works best with the factory ecu as far as power.(timing, etc)

Again don't take my word for it but read up on it and chances are you will come to the same conclusion but maybe not. :fp: With an aftermarket ecu it is definitely better to go with a lower temp thermostat. (180*F)



As far as the Water Wetter goes that is interesting info Adam. I honestly believe i have a abnormally clean and well maintenanced car because the coolant looked like it had just been changed when i put in my 42mm CSF radiator and new radiator/coolant hoses and i had it for 1.5yr when i did it and even the hoses seemed that they had been replaced but the radiator appeared to have been original and had developed a small crack, thus the rad replacement.

HarryB
10-16-2015, 02:19 AM
Well, haven't thought of that; apparently a temp-based map (or temp. correction) on the ECU for timing. How did you find that out? Measured timing before/after?

Also, what people think of this?
http://www.evanscooling.com/
IMO it is an overkill for our cars, but it came to my mind as i was reading this topic.

Greasemonkey2000
10-16-2015, 09:53 AM
No simply reading up on various forums about how the factory ecu tune was 'optimized' to use the factory 195°F thermostat, again i can't recall the specifics beyond that but i had already bought a 180°F thermostat and after coming across some relevant information i dug deeper and decided to get a 195°F till the MS3 was installed and then i would change to a 180°F.

mx54life
10-16-2015, 09:57 AM
What I also found very interesting is that when draining, after the last drip jack up the rear of the car and you will see another 2 liters flow out. I measured very close to 6 liters out after lifting the rear.

"But the burping is a little challenging, you need to squeeze pump the lower radiator hose several times while the front of the car jacked up as high as you can. If the car get hot than normal, relax turn off the engine and repeat the process. You will have over flows so you need a huge funnel/spill free funnel. Be patient once you get that air pocket out your temp will normalize."

HarryB
10-16-2015, 09:57 AM
The one I was looking into is even lower. I think (top of my head) that NB2 OEM one is 180F, and have installed a 72 deg.C/160F in a friends' NB2 lately. On his, operating temps are around 190 now, rarely going over 195. Mine (with OEM thermostat) operates around 195F, both with IL Motorsport aluminum radiator.

BoBo
10-16-2015, 10:04 PM
Always use distilled, unless it's an emergency and tap water is all you can get at the moment. You can go to Firestone they have "coolant vac" RTI, Uview, or stuff like "Flow Dynamics C-vac machine" that suck and fill the coolant in one.

You can do it manually as well, but like a few people mentioned here, replace the hoses and thermostat. I prefer OEM Mazda parts and Gates for aftermarket. Good luck.