mistamystery7

I'm so happy!.....i had gone almost 3 weeks without a problem, and i was startin to worry....yeah im being sarcastic...........anyways


for the past 3 months my water temp has been fine, but all of a sudden, 2 days ago when it started to get hot out for the first time here in maryland, i noticed when i was sitting at a light my temp gauge started climbing, climbing high....it didnt get to the top and the buzzer or light never came on, but i dont know where to start looking for problems. the coolant level was full, the ast looks fine from the top, and i dont think any coolant is leaking. the only thing i noticed is, (i just bought the car from texas about 3 months ago) but since i got it, when you shut the car off you can hear a loud burbling sound comming from the engine bay, and when i got a closser look it sounded like it was comming from the elbow and the ast lines.....i felt the ast lines and can feel them moving liquid or air or whatever through the lines..................so any ideas? anyone? i dont want the car to overheat so i wanna start lookin but dont know where to start.......also could it be the thermostat getting stuck?

jdhuegel1

Gurgling = coolant boiling.

Are you SURE it's full? I'd try to burp it real good a few times. Also, do you know what the ratio coolant/water is?

spurvo

Well, you are definately going to need to do some work. If the stock gauge is moving (and you haven't performed the gauge linearization, or it wasn't performed before you got the car), then your temps are hot enough to approach intermediate housing warpage, which leads to a burn through of the O-rings that seal the housings, which leads to engine rebuild.

The slurping sound is pretty indicative of air in the system, which very easily occurs in this car, given the number of pathways for coolant to move. So to start with, are you positive that there is coolant at the top of both the AST AND the filler neck (next to the alternator)? If not, you need to top these off, run the car through one heat cycle, then let it cool and fill it again. Occaisonally, you need to "burp" the air out of the system, as it has gotten trapped in an area of the block, and needs to be manually removed. One way to do this is to pull the rear throttle body coolant hose and fill the filler neck until a bit spills out of the TB hose connection. BTW, the connection I'm talking about it the hose that points towards the passenger side of the bay, coming off the top-backside of the throttle body. Another technique is to squeeze the upper radiator hose to work air out of it and other sections. this does require you to pull the intake, though.

Next, it is quite possible you have a pinhole leak in the system somewhere, which is not allowing it to come to full pressure (14 hoses with 28 connections!!). This in turn will allow the coolant to boil, which reduces its cooling efficiency, which leads to overheating. A bad cap on the AST or the filler neck (note these are different types of cap. The AST has the spring, whereas the filler neck cap is just a flat cap, no spring) will also lead to reduced pressure in the system.

Further, you need to make sure your fans are coming on at the proper times. With our cars, the fans usually come on at pretty high temp (221F with the lights off, 206F with the parking lights on, or some other electrical loads, such as the heater blower on 3 or 4, or the rear defrost on), but the stock gauge will not have moved by this point. Thus, if your gauge is going higher than the middle, are your fans turning on? If not, this is the source of the problem, and needs to be fixed ASAP.

Finally, of course, the T-stat may be sticking closed. In this case, the fans can come on but the temp keeps going up no matter what. If this is the case, then you need to swap out the T-stat. USE THE OEM stat. It opens at 176F, is nominally open at 180F, and fully open by 195F (I think). It also has a jiggle pin and hole that allows small coolant flow and more importantly air to move through the system with the main valve still closed.

So, confirm your fans are working. If so, burp the air from the system (good idea to do this anyway). Confirm your filler neck cap is sealing (any steam or hissing from it when you shut off?), and get the AST cap pressure tested (or replace it, but even then, brand new caps can be faulty. Ask me how I know!!). If you still have overheat (gauge moves from horizontal at ALL), then get a coolant system pressure tester (really a necessary tool for these cars!), hook it to the filler neck, jack up the car, pull the undertray, start the engine, let it just warm up, pump the pressure tester to ~11 lbs, climb underneath and start looking for the green pee. It's a pain in the ***, but it works.

Lastly (no, really), all hoses should be replaced if they haven't already been, the AST needs to NOT be the stock plastic POS, the radiator could stand to be replaced if it's stock, you need a fan mod, AND a better method of determining temperature, such as stock gauge linearization or an aftermarket gauge.

Hope this helped. Sorry so long!!

DeaconFrost

I had the same problem...your coolant is boiling (as stated above) because there is not enough pressure in your cooling system to keep the boiling point as high as it should be. I dont know how to fix this...inspect all your hoses for holes...cracks...leaks...even a tiny hole can affect it. And burp it...and burp it...and when you think its done, burp it again.

I also bought mine in TX...did you get it from a dealer?

Sean

DeaconFrost

^^ good write up.

rx7raca

if think you feel air in the lines...that would usually mean there is. best thing to do is flush out the coolent system.

One thing I use to do when I was coming to a stop or was going to be sitting for a while, is turn on the a/c, so the fans come on. this will help with cooling.

if your still getting to warm, buy an aftermarket raditor, but only if you really need to.


one test you should do, when you put the new coolent in.(and full) when the car is cold, leave the filler neck cap off, and have someone turn the engine over. if coolent comes bubbling out. then you need to replace the coolent seals. Im not saying this is your problem, but this is what happened to me when my coolent seals went.

let us know what happens when fill it up.
good luck

mistamystery7

ok guys , here is a little bit of an update, i bought a new thermostat today, and im gonna try that tomorrow, but today i checked the fluid levels in the filler neck and ast, both were low about 1 1/2 inches i guess, so i filled it up with some distilled water, i drove through A LOT of sitting in traffic to get to the mazda dealer, and i ALSO turned on my parking lights, because i read something about that on here.....but the temps stayed normal all the way thru traffic, and when i turned off my parking lights to see if that made a difference, thats when the temp started rising again.......any ideas? also, has anyone changed their thermostats, can you gimme a little advice on how to get to it?, thanks guys

mgoddard1

Make sure that the lines going to and from the AST aren't kinked. If they are kinked the cooling system over time will push coolant to the overflow tank and not back in (ask me how I know this). Having air in the system will obviously cause gurgling and higher than normal temps.

jajiddam

so if the coolant is bubbling is that a bad thing?? i took my car out for a drive last week and i pushed it a bit and when i came back in the garage and opened the hood, i heard bubbling noises..

EVS.TurboTuner

What does parking lights and high temperature readings have in common??? Sorry I know nothing about this, so could someone enlighten me?

Fatman0203

The fans go on soon when the parking lights are on or so Ive heard. I just put my A/C at 1 or 2 and bam there are your fans on.

spurvo

Parking lights (head lights too, of course), interior blower fan at 3 or 4, or rear defrost ALL trigger what is called the electrical load sensor (E/L in the manual). When this happens, it sends a signal to the ECU which 1) raises the idle from 750 to 850 rpm via the idle speed solenoid, and 2) allows the ECU to trigger the fans to come on at low speed at a lower temperature than otherwise. Specifically, with no E/L, the ECU turns the fans on at 221F. With E/L, the low speed comes on at 210F.

When I first got my car, some total F**K had placed a REALLY bad cap on my AST, and had opened the plug behind the cap, which was weeping. This was before my gauge was linearized, so I would drive it and notice the fans coming on all the time. It was due to the system not holding pressure. The fans would keep the temps from running into the red, but either I or the previous owner overheated it at least once under this condition, as I had subsequent O-ring failure (took about 6 months to materialize). I figure the guy knew... no way to have really tested for it, either, unless I had brought a pressure tester at the time. Of course, he had it warmed up when I got there anyway. Sigh...

So, mista, I'm betting you have a small leak somewhere in the sytem, or your cap(s) are bad. Get a pressure tester and check your system SOON! Quit driving it like this, or you WILL have to replace the engine.

RX7Wishing

Added this thread to my favs.. good writeup. im flushing my coolant this weekend

dubulup

spurvo has been the cooling man in my book!

always great (entertianing) write ups and always chimes in when dealing with cooling!



HATS OFF TO SPURVO!

spurvo

Well... sniff.. I just want to thank EVERYbody.. it's been such a long hard road for me.. and, I just... now I know you really LIKE me! YOu REALLY REALLY do LIKE me.. I just....

I still get a chuckle out of that pic! Thanks dubs...

novadan67

Ha Ha that is a great pic! I am sure we have all felt like that before when working on these cars!

Skeltah

[QUOTE]Originally posted by mistamystery7
[B]I'm so happy!.....i had gone almost 3 weeks without a problem, and i was startin to worry

Don't ya just love that rotary engine. :-) Never a dull moment.

dubulup

no problem bud!