AKA SIR

I am a new FD owner and I thought I would get my car ready for spring with what I thought would be some simple, easy maintenance... a coolant flush. I did multiple searches on the forum, read Rob's write up on the coolant flush and read the FSM. I planned on following Rob's write up with the double flush of distilled water. Well 5 hours later I am still no where near done, have done countless searches and am frustrated as all hell.

I bought 10 gallons of distilled water and a Lisle funnel.

I started by raising the front of my car so I could easily get under it. It had been sitting in my garage all day so it was cold.
I removed the filler cap (the one with the yellow sicker on it) to relieve some pressure and put it back on.
Crawled under the car and removed the plastic drain plug through the 1" hole in the plastic "rock guard" on the bottom of the car. Coolant slowly began to leak out.
I them removed the filler cap (yellow sticker) and the cap on my aftermarket AST. I could hear the coolant coming out much faster.
It only took a couple minutes and coolant stopped coming out. In all, about 2 gallons drained.
With the drain plug still out, I poured half a gallon of distilled water in the filler cap (yellow sticker) and heard it drain out the bottom.
I cracked opened a beer and thought about leaving my job to become a mechanic things were going so well.
My next step was to put 2 gallons of distilled water in the system, run the car for 3 minutes with the heat on high and then drain.
With only a couple sips of beer enjoyed, here is where I started running into problems and unanswered questions...
I put the drain plug back in, put the AST cap back on and started pouring distilled water in the filler cap (yellow sticker). I made sure to pour very slowly.
I only got about half a gallon in when it seemed like it wouldnt take anymore. I figured air was in the system so I reached my hand in the engine bay under the filler cap and squeezed/shook the hose a coupe times. I could see that released some air and it was taking a little more of the water in. After 5 minutes of doing this, it was going VERY slowly. So I crawled under the car again and removed the plastic "rock guard" on the bottom. I then squeezed the large hose that connects to the bottom of the radiator. I could hear it taking in a little more of the water, but not much.
At this rate it would take me 4 hours to get 2 gallons into the system. Each squeeze of the hose got me another small bubble, but that was it.
I decided to drain what I had in there and try filling it up via the filler cap (yellow sticker) but using the Lisle funnel this time. Same result.
At this point my beer was not tasting too good so I moved to Jack and began to drink my dreams of being a mechanic away.

Well it is 2:00 am and I dont know what to do. I have done a lot of searches and I now have more questions than answers. Please help

Questions
1) Is my process of filling the system correct? Like I said, at the rate I was going it would have taken me 4 hours to get 2 gallons of water in. Then I would have needed to run my car, drain the water and then another 4 hours to put the coolant/water in.

2) Is it necessary to remove the block drain plug? Rob's write up did not say to do it (the ones below his did). So I dont know if this is necessary or not.

3) When I am filling it, should I be adding it to the filler cap (yellow sticker) or the AST cap? I would think the filler cap however the YouTube video of the guy using the Lisle funnel is adding it to the AST.

4) When I am filling it, should all the caps be off? Or should they all be on with only the cap off the one that I am filling it through?

5) In many of the posts people talk about removing the TB coolant hose while filling it up. This is supposed to help air escape and make it easier to fill. I was never able to find a photo showing the location of this hose. People say it is back by the firewall but there are a lot back there. Does anyone have a photo of it they can post?

6) In some of the posts people say that because the car is cold, the thermostat might be closed, thus preventing coolant from going in. I did start my car with the Lisle funnel on (and only 1/2 a gallon in) and immediately the Add Coolant light and buzzer came on. I turned off the engine right away because I wasnt sure if it was ok to run the car in this state (with only 1/2 gallon of distilled water in it) and didnt want to ruin anything. Was this good? Or should I leave it run and just ignore the Add Coolant light and buzzer?

7) Kind of unrelated, but the cool that drained was green. The coolant I got at the store was yellow and I couldnt find any green stuff. The label says it is safe for all cars. Is this ok to use?

Again, sorry if all these answers are somewhere else in the forum. I did a lot of searches and it seems every post I found gave me more questions than answers.

EjCabrera

iTrader: (4)

i'd recommend getting an upgraded radiator, ast, hoses, radiator cap first. I think the problem is that your not burping it properly

ksu-chewie

iTrader: (14)

To me it sound like you were having problems re-filling because you had the car still lifted. I know when did this last year, after I lowered (leveled) the car it was able to take a lot more coolant into the system. If you're front is still on jack stands, try raising the rear up some with a jack to level it out and see if you can add more coolant. Starting the car for a few moments and letting the water pump run will help create some pressure and move coolant around.

The block drain is not necessary, but does make it much easier to get all off the old coolant out of the system in one pass. Using the the radiator as the drain will require a few fills & flushes to get out all of the old coolant.

adam c

iTrader: (2)

Disconnect the throttle body coolant line to allow air to escape while adding coolant.

AKA SIR

I want to do this, I just dont know what line I should be disconnecting. I did a bunch of searches but never found a photo. Does anyone have a pic of the one to disconnect?

AzEKnightz

iTrader: (24)

You've gt the Lisle funnel, why not use properly like it is meant for? **Sarcastically saying**

Now back to the help!

Pour coolant until you fill up about 1-2" above radiator level inside the Lisle funnel. Start the engine, turn the heat to max and blower to LOW. Watch it burp and add more coolant =).

Good luck and have fun, this method NEVER failed me even on RX7s.

However NEVER fill up the Lisle Funnel more than 1/3 of it's capacity because before thermostat opens, it "sometimes" when coolant are getting hot and expanding/water pump flowing coolant. It will PUSH some of the coolant above the Lisle funnel (fill it up and spill some), therefore I usually kept it BARELY above the radiator level and add as necessary.

Ff you are still stuck, I would recommend using a HOSE and flush water down the radiator as I believe you might/can have a semi-clogged radiator.

-AzEKnightz

AzEKnightz

iTrader: (24)

Here's a picture of the coolant hose on the TB.

-AzEKnightz

RotaryRX-007

Throttle body. Find it. Look at it. On the side closest to fire wall, there is a 3/8" coolant line attached with a clamp. The only coolant line around. That's the one.

Pull it and snake it in between the brake lines on the wall to hold it upright. Add coolant. Run the car. It's not gonna drink a lot of fluid until the thermostat opens. Just be ready to add once she starts getting warmed up. Remember, stat isn't going to fully open until 180*f so she's gonna be warm warm. Not gonna hurt anything. There's still fluid in the block. All is ok. Just go start the thing and disconnect the TB line. You'll be fine.

Tem120

iTrader: (5)

its right by the throttle body its pretty obvious what it is its the thicker hose that goes up there , its much thicker then the surrounding vacume hoses

AKA SIR

Thanks for the input guys. I will try it later today. So just to be 1000000000% sure... it is ok to run my car for 3-5 minutes with the Add Coolant buzzer on (if I just put in a 3/4 gallon of distilled water)?

RotaryEvolution

iTrader: (30)

sort of, 5 minutes is about max with a huge air pocket in the system since there is no water to cool things cycling through the engine. it will heat up rather fast and overheat even faster if you run it much longer than that.

scotty305

iTrader: (2)

The Add Coolant buzzer is just a low-level buzzer, the alarm should not sound if the water level is all the way to the top of the coolant fill neck. The buzzer will remain on for a good 10-30 seconds after it has been tripped, even if the level is only low for a second or two. The Lisle filler shouldn't interfere with the operation of the low level buzzer, by the way.


Personally I'd remove the coolant hose near the throttle body if you can get at it. See photo below. Then I'd attach the Lisle funnel to the coolant fill neck and leave the AST uncapped while you are filling the system. Leaving the AST uncapped and throttle body line disconnected will allow another path for air to escape the cooling system. Then, install the cap on the AST once it is full to prevent it from overflowing. Re-attach the throttle body coolant line once it starts overflowing also, you may want to put a rag or a towel nearby to prevent the water from making a mess in the engine bay.


Note that the Mazda factory service manual recommends a very slow fill rate, maximum one litre per minute. That's one 500mL bottle of drinking water over a time period of 30 seconds, which is painfully slow. Filling at a faster rate will help trap air bubbles in the system.

AKA SIR

UPDATE: Thanks for the help guys. The trick was definitively to undo the TB coolant hose. Note that my car is stock so mine did not look like the pic that AzEKnightz posted (it must have a lot of mods). Mine looked just like scott305's pic. Both helped me identify the correct hose. Once I did that it quickly gulped up a lot more water (with the AST cap off too). Between that, pulsing the hose right below the filler cap and pulsing the hose underneath I was able to get enough in it so I could drive it around for the weekend without the Add Coolant buzzer going off. I plan on draining the water I have in there and putting my coolant in tonight or tomorrow.

scotty305

iTrader: (2)

If your car still has the stock radiator, AST, and old coolant lines you should seriously consider replacing them. The AST is very easy to replace, personally I removed mine and replaced the original filler cap with an FC filler neck. Swapping the stock radiator isn't too bad, should only take a few hours. I got a cheap CSF Racing radiator and the drain plug galled the first time I used it... I'm not sure what is the best option for aftermarket radiators but it seems Fluidyne and Koyo are popular options.

Swapping out all the stock coolant lines takes a lot of work, prepare to have the car down for at least a few days unless you've got some friends who are professional mechanics. Think of the oldest, nastiest rubber band or garden hose you know... then realize that the coolant hoses in your car are at least 17 years old. Ray at Malloy Mazda sometimes had package deals on all the coolant lines, he can get all the right parts and ships quickly.