HellPhyre

Hello, I'm a new rx-7 owner, have lots to learn. I'm having a problem with air bubbles in the radiator, at first i just thaught it was like that from prev owner so i filled it up with 50/50 and left it at that, the next day the light came back on and another bubble had formed, theres a 2 pronged sencor that has gone out on the bottom of it i need to replace, dunno if thatd cause this, tonite i was out with a friend saw a new mustang gt and i pushed the car kinda hard seeing what it was capable of, when we got to a store to get a drink the add coolent light came on and stayed on (the last few times itd just come on then off shortly after) when i put my hand on the radiator the water was boiling, but my temp guage wasent reading hot, just below the middle as a matter of fact, could the sencor be the prob? or do i have a seal out? i really need advise, please respond. btw its a 88 n/a vert.


PS: i stumbled upon this place when i was looking up about the engines when deciding to buy the car, id have never thaught id find sutch a gold mine, wonderful info and made me decide on the 7 above the rest.

xeroguitar2003

there is a bleeder screw at the top of you radiator take that out and then fill your radiator the put it back in, if you dont do this you will never get the air bubble out.

HellPhyre

Well, it seems the moron who had it before took out the bleed screw out and plugged it up with jb weld, and me being the moron i am thaught the sencor at the top of the radiator was the bleeder screw and kinda snapped the wire on it.....guess its time to look for a diff radiator, thanks for your help xero

HellPhyre

On second thaught, could i just drill a hole on top of where the bleeding screw is and make my own bleeding screw? would save alot of time and money and btw i found out that the sencor i broke is a pain in the butt to get, both autozone and oriley's dont carry it there both stateing that ill have to either order one from mazda (whitch they both frowned upon saying) or find one in the junk yard, only prob is the rx-7 is a verry rare car around these parts, hope to get it fixed soon and please respond about makeing my own bleed screw idea.

NZConvertible

Don't bother replacing the sensor at the bottom of the radiator. It's a temp switch that is of minor importance to the emission control system only.

The coolant level sensor on top of the radiator is part number N326-15-610 ("Sensor, Water Level"). Quote that number to Mazda and they should have no trouble getting on in for you.

Unless you live in the Arctic, you don't need a 50/50 water/coolant mix. As per the FSM for temps down to 3degF you only need 65/35.

Here's the correct way to successfully fill and bleed the S4's cooling system:

1. Put the heater in the HOT position (you'll need to turn the ignition on first to operate the stepper motor). Leave the heater on until your test drive at the end.
2. Make sure both the engine and radiator drain plugs are installed.
3. Remove the filler cap on top of thermostat housing, the radiator cap and the bleeder on the side of the top radiator neck.
4. Begin filling the water/coolant mix through the radiator neck until it reaches the top, then replace the radiator cap.
5. Continue filling through the filler neck until the bleeder overflows, and replace the bleeder cap (don't overtighten it or you'll ruin the plastic plug). Continue filling until the water/coolant reaches the top of the filler neck.
6. Start the engine and let it idle. The water level will probably drop a bit when the engine starts as the pump pushes the water into air pockets. Keep topping up the system as necessary.
7. Keep the engine running until the thermostat opens. You can tell when this happens as there might be another drop in water level, and the top radiator hose will start to warm up.
8. When the engine has reached operating temp and no more air bubbles are appearing in the filler neck, replace the filler cap.
9. Fill up the overflow bottle to the correct level.
10. Go for a test drive, keeping an eye on the temp gauge. Make sure the engine reaches full operating temp but does not exceed it, and check the heater operates properly.
11. On your return, once the engine has cooled down, recheck the level at the filler cap (not the radiator cap) and the overflow bottle.

Fatty_FC3S

Im going to make this REALLY EASY for you!

1. Find a Snap-on truck
2. Buy the yellow funnel kit with radiator cap adaptors
3. Spend 30 bucks on kit
4. Install proper cap and funnel onto radiator
5. Fill 1/2 way with coolant
6. Start and warm up car with heater on full
7. Bubbles will work their way out (may almost overflow!!!)
8. Turn car off, let coolant suck back in.
9. Let car cool for awhile with funnel on. Repeat a 2nd time to get all bubbles out
10. Cap off radiator, pour remaining coolant from funnel into overflow tank.

You are done, no guesswork and now bubbles. BEST 30 bucks i ever spent on a tool for my rx7!!!!

Graham

Sideways7

iTrader: (7)

On s4's (86-88) normal temp is at about 1/4. If it gets near half, its overheating. My guess is that your problem is a blown coolant seal and the engine is pressurizing the coolant system. Search around about checking for coolant seal leaks, its pretty easy.

NZConvertible

Since the method I just posted is just as easy, doesn't need to be repeated, works every time and costs nothing, I'd say you wasted your money...

HellPhyre

one of the problems is the person before me jbwelded the bleeder valve shut, so i cant use the bleeder valve at all ;/ will try Fatty_FC3S's idea, thx for advise.

RXgirl7

dont trust the stock gauge-it has 3 settings: "cold" "normal" and "congradulations, you just cooked your motor"

i would reccomend buying an autometer or similar brand gauge with a range of 100-250(or more) summit has them for less than $40. if you have the stock T-stat in your car, normal opperating tems are 180-190 or so, depending on how hard your driving and ambient temps.

do you have the stock metal and plastic rad, or something else?

HellPhyre

It's all stock, was working in the tuneup when this happoned, guess the cars outta commission until i can get the new sensor in and check it for leaking seals ;/
still any advise is welcome or ideas, couldent find the snap on part you was talking about fatty_FC3S, so still looking for options besides getting a new radiator, i will if its a must.

Sideways7

iTrader: (7)

I still say you should check for coolant leaks. Do you get white smoke at startup? My car's coolant mysteriously disapeared, and it turned out i hade a crack in the coolant passage.

HellPhyre

YES! i do! how hard will it be to replace the coolant passage?

zeromage428

1/2 way is overheating?? i never knew that, all well my koyo keeps my engine nice and.....cool/hot.....yeah lol

NZConvertible

That applies only to S5 temp gauges, not this S4. S4 temp gauges are linear, and will rise and fall in line with coolant temps. This is the second time I've told you this.

EDiddy

HellPhyre

Please help, i went to a radiator shop to ask about getting a new coolant passage, and he sent me to a import shop, well i told him the symtoms and hes telling me that its a blown apex seal please tell me it isent so! here are the symptoms, car runs fine, just after a few hours the add coolant light comes on, I thaught it was a bubble in the radiator so id fill it back up same thing would happon either in a few hours or the next day, occasionally when i start the car a buntch of white smoke comes out of the pipes and every now and then itl idle a tad low but would go to normal idle after a min or so, once again please help, noone around here works on a rotary so basicly id have to give up my dream car

HellPhyre

When the white smoke comes out the pipes it quits after a min or 2 of idling, and the reason im sceptical of the mechanic is because he dosent know rotary engines, he dident even know what the seal was called, please any info would be more helpful then none.

HellPhyre

it drives like a champ im having no problems driveing it for the exception of it losing water, the engine heats up real fast took it to the gas station and around the block got home and it was hot to the touch well the radiator cap was

HellPhyre

LoL I went to the radiator shop today to see if he could help, turns out the seals on both caps were fucked whitch means 20 bucks for new caps = no more losing coolant just replaced them, drove it hard for about 15 min waiting now on it to cool off to see if any water is missing, went underneath and no leakage from what i can see, verry pleased it wasent sompthing seriouse, thank you all for your advise and help.

HellPhyre

Well....still leaking water took it around the loop a few times and yet i still have leaking problems, but ive narrowed it down, its comming from the front, dripping off the bottom of the front bumper, should i replace all the coolent hoses?

HellPhyre

sorry to be sutch a pain but when you mension rx-7 here mechanics tend to run away
and the ones that dont are complete retards and tell me my moter is blown and i need a new one without even looking at it

Fatty_FC3S

Quote: Since the method I just posted is just as easy, doesn't need to be repeated, works every time and costs nothing, I'd say you wasted your money...


Not really. Makes no mess, easy to fill, and has adapter include that fit my Acura Legend and 3rd gens. Its not ONLY for FC's ;-)