folks... I am getting ready to flush the coolant this weekend, and a buddy of mine was going to help me out. He has a 2nd gen, and this was his advice. Could you please read over and verify if this is right or wrong? I was reading through scuderiani and robinette's how-to's and no where does it mention using a garden hose or replacing a gasket or removing the thermostat... Which directions should I follow? Also, do I need to worry about the coolant going into the turbos? I hope not...

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If you have a plastic aerodynamic cover under the front area of the engine like on the 2nd Gen, you will need to remove that first. Drain your coolant from the radiator (there should be a small plastic screw on the bottom of the radiator). Remove the caps from the radiator, etc so that everything will drain out. There should be 2 hoses going to the radiator; remove the bottom one to completely drain the radiator and most of coolant out of the engine. You'll be pissing fluid all over, so make sure you have plenty of catch pans and stuff to wipe up.

Once most everything is drained, you will need to remove the coolant neck and thermostat. This is the little neck on the top where the top radiator hose connects to the engine. It should be held down by 2 bolts. Once you pry it up, you will find the thermostat sandwiched inside. Take it out and set aside. Use pressurized water from a garden hose and pump into the opening where you just took the thermostat out. This will flow the fluid backwards through the engine. Flush until fluid coming out the bottom hose looks like clean water. Then do the same through the top of the radiator letting it drain out of the bottom hose.

You'll want to get a new gasket for the thermostat and coolant neck. Should be at any parts store. You can put the old thermostat back in, or replace with a new one as long as you have it out. Put every thing back together and refill with coolant. You will need to run the car for a little while and keep refilling as all the trapped air works out.
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Just to clarify, is the process of flushing the coolant as simple as this? Namely, drain coolant from radiator by removing plug, then reinstall plug, then fill with distilled H20. Run car for 3 minutes with heat on, then shut off, drain H20, repeat process once or twice more, then finally refill with a COOLANT MIX (40-60%)? If so, then it should be pretty simply... of course, I have to burp by squeezing the radiator hose? the lower one?

thanks guys...

 

I bought an actual flush kit from walmart. Installed it inline between the Collant neck and AST. Opened the rad plug and turned on the water hose. Also, open the AST and install the flow elbow that comes with the kit. Ran in for 15 min or so with the heater on high.

 

I do not suggest 'flushing' the coolant, since you will be putting tap water into the system. I suggest draining and replacing a couple of times using proper distilled/coolant mixture. I'd rather have a little old coolant left in the system than any trace of tap water. The turbos hold a little coolant, but not much. Changing the thermstat is a good idea, but a separate thing from a coolant flush and you have to remove stuff to do it. I say let that wait until the next time it's convenient.

How I've done it:
- lift the front of the car, cold engine
- remove the underbelly pan
- open the drain of the radiator (don't strip it!! find the exact size screwdriver!!) over a 5 gal bucket
- pop off the coolant hose in back of the throttle body
- take off the AST and water pump body caps
- drain the coolant from the engine block - the bolt is on the center housing, driver's side, just a couple inches above the oil pan.
- refill system, burp free of air (the trick is pulsing the lower radiator hose)

Repeat the whole process again the next time you have the front of the car up (next oil change?). Make sure you've run the heater on full blast for some time in between to get that coolant moved through.

Or, for the last step fill with only distilled water, put the hoses/caps on, and run the engine with heater on full blast for about 10min. Then let the engine cool, drain all water. If you want to be really **** repeat this process until the water runs clean and clear, but really just one run with distilled is good. Then finally refill with coolant.

 

dgeesaman... in your last sentence, when you say refill with coolant, you mean the actual mixture and not pure coolant right? Is 50/50 a good mix?

Also, my first post (the quote) said something about replacing a gasket... is that needed?

 

Right, I use 50/50.

I am not aware of any gaskets that need replaced unless you're taking off the water pump housing to change the thermostat. If so, call Ray at Malloy and get a new one with the thermostat, as well as new caps. The bigger evil of FDs is the coolant hoses, especially the turbo coolant hoses. I suggest getting that done and having the t-stat changed then.

Dave

 

thanks.... I will have to look up Ray from Malloy Mazda's number. I'll replace the gaskets next go around, not this time. Also, any idea on total quarts I will need for the final refill? Once distilled H20 has been drained from the radiator and the block? That way I'll know how much to get... If I put the right amount in, and I burp the system well, do I still need to worry about the coolant buzzer going off while I'm driving? It's prolly not a good thing to drive more than 30 seconds with that buzz going right? I hope I don't get that buzz...

 

You need to do some reading. The quantities and stuff are published. So is Ray's number.

I would expect to get a buzzer, and 30s is not acceptable to me - more like 3s. I just drove mine around the block a couple times after a good warmup and had some extra water with me.

Dave