Jon_Rhea

I read somewhere on here where somebody flushed they're coolant system and a question was asked to them if they had changed the thermostat. They then stated that a higher temperature thermostat should be used. What is the reasoning behind this? Why should a higher temperature thermostat be used over just the stock one. Also, does the t-stat need to be replaced, or is it just good practice to replace it now and then? I'm not having any issues with my heater or any overheating issues with the car. Also, I'm flushing the system because the shop that did my timing belt used the green coolant instead of G12. Are there any additional steps I need to take in order to insure that all the green coolant is out? Is there any sort of system cleaner that would help remove all the green coolant? I plan on replacing the coolant expansion tank as well.

Thanks!
Jon Rhea

Jsmooth65

You'd be surprised how much comes out from its hiding spots. That or a water hose if you don't mind the mess.

randommisfire

The way I flush coolant is a little tricky, you have to be very careful not to burn yourself with the toxic coolant. This just might be the most effective way to flush your system.

Only use this method with vehicles that have the big plastic blue screw-on coolant cap and after you've read the instructions.

First, warm the car up until the temp gauge reaches half way. Turn the car off and wait a few minutes, carefully/slowly open the coolant cap to release the built up pressure(this is how you can burn yourself if you open too quickly). The reason for this is so you can flush the cars' coolant while the thermostat is open.

Pinch off the coolant bottle return line with hose clamps(it should be the highest and smallest one[also, note the hoses are still warm]) then disconnect the hose and get a similar size hose(about a meter in length) with a coupling to connect the return line, after your connection remove the hose clamps. Then take the return line with the newly added extension and route the hose straight down into a large catch can (making this the lowest coolant line).

Start the car and monitor the coolant level, since the return line isn't supplying the coolant reservoir, its now being flushed out by the car's pressure(example:water pump,or heat). Make sure that you are constantly filling up the reservoir with fresh water from a garden hose or something equivalent(filling process needs to be fast). Keep in mind that since you are filling up the car with new liqiud it is not the same temp. so the gauge will drop and thermostat will want to close(if necessary let engine coolant heat back up). Just make sure that you do not overheat, and try to keep air out of the system(you can squeze the feed line to force air out).

So the goal right now is to let the car flush out its own coolant while you add fresh water to the system. You should notice the coolant color becoming lighter due to the water. Wait until the return line is pouring out clear water. Once it is clear start adding an entire gallon(or more) of G12 coolant, next you will see the return line dispensing light pink fluid.

If you live in a place were it gets below freezing you're going to want to have 100% coolant. If you live were its always hot you should leave more water than coolant. Just make sure you know which ratio to use.

Now you're almost done, turn the car off, pinch off the return line with hose clamps and remove the extension, reconnect the return line to the coolant bottle reservoir, and remove hose clamps. If you own a coolant pressure tester, bleed out any air from the system. If you don't own one, just top off the fluid and wait a while until the car cools down, this way the air will escape on it own. After letting the car cool down, top fluid off again and take a short test drive, make sure to bring extra coolant just in case. Once you get back let the car cool down again and recheck your coolant level. After you're finished clean up should be easy. Ideally
there shouldn't have been a drop spilt, but being realistic, things happen.

If at anytime you are unsure of what you're doing just stop and take you car to the dealer, a coolant flush is not worth injuring yourself or damaging your car just to try and save a buck. Theoretically this method of flushing a cars' cooling system is very basic, and the process takes anywhere from 10-20 mins. Be safe,smart and carefull, make sure you understand the directions first.