View Full Version : Coolant sensor goes off at random times?
04-07-2008, 06:48 PM
Well, I just did a coolant system overhaul because my car was overheating: I put in new hoses, new thermostat, new thermostat gasket, new hose clamps, flushed the rad with distilled, and took the AC condenser out that was blocking airflow to the rad. (Also, I drained the block, and the rad. coolant came out pretty dark, but maybe it's just the Presone Radiator cleaner I put in there?
Right now, when I start my car with the water level all the way filled, and the cap off, coolant DOES NOT burst out of the rad with "excessive force"
I had a thermostat gasket leak before, and the car would not "siphon" the coolant back out of the reservouir, but now that I put a new gasket in, it does it just fine!
Ok, so I start it, warm it up, and drive it around a bit. after about 10min or so, my coolant buzzer goes off, and sometimes STAYS on, while other times, it shuts off, and later comes back on. It's really intermittent, but the car has done it both times I drove it after I redid the coolant system.
Now, notice, the original owner said that the coolant buzzer went off on him too, and he couldnt figure it out. So, he took some wire and just grounded it to the - post on the battery. I hooked it back up, and now it does this.
I'm kinda confused, and think that my engine blew a coolant seal.
Also, there is a "gasoline" kinda smell in my oil. I just changed it about a week ago, and havent really been driving the car too often, but I let it warm up every time, and drive well, too.
EDIT: And I did "let engine idle with rad cap off and heater system set to high to bleed it"
04-07-2008, 07:44 PM
Is your coolant sensor plugged in too? You know, the one that sends the signal to the BUZZER?
04-07-2008, 07:58 PM
yes, that's plugged in. IT was getto rigged, as I said, and I plugged it back in.
04-07-2008, 08:31 PM
well, you reinstalled it but are you sure it's working properly??
have you pressure checked your coolant system?
Our car used to do that and it turned out to be the t-stat was cracked and only leaked under pressure.
04-07-2008, 08:57 PM
Yeah, my neck is pretty nasty.... so you replaced the neck, and it stopped doing this?
I DO have a tiny crack in my neck, and about to replace it actually, but there is not a lot of coolant that I can see coming out of there... like, no puddles, or wet spots, or anything like that. I checked. Do you really think that this could be my problem? I highly doubt it atm.
I read about hitting your coolant sensor with a hammer, and was wondering about how to do that? Is there a possibilty that perhaps there is a loose connection somewhere in the harness?
But then, wouldnt the coolant buzzer go off even when the wire to it is grounded off?
Oh, and I think there is a LITTLE bit of oil in my coolant as well.
04-08-2008, 04:01 PM
a pinhole leak can cause an intermittant add coolant buzzer, particularly on the freeway
04-08-2008, 04:08 PM
yes, It's never buzzed at me since. When the car is cold and not under pressure then you won't find the leak that's causing the buzzer to go off. Do a pressure test and see if you can find the leak.
TUrns out that the hot coolant would evaporate when under pressure and at operating temps so I never say a puddle or leak. When I tested my system I was peed on by the T-stat neck so that's how I found the crack.
04-08-2008, 07:21 PM
Hmm, mine does the same thing, and I slowly lose coolant also. But I also smell a tinge of coolant near the turbo so I think I might have a small leak down there also. I just always top off the system once a week to play it safe.
Good catch on that Phoenix.
04-08-2008, 08:01 PM
we learn from the mistakes and experiences of others. :001_005:
04-09-2008, 12:17 AM
Well, I was about to have money to do my brakes (f+r pads, new rear rotors, and a new Master Cyl) as well as a new neck.... but I am about to go pick up a newer engine with only 100K on it, and a new clutch for $200, so my monies are a bit dry, and it looks like the car will have to sit for a little bit. untill I can save up enough for brakes, and to get a new neck. If the neck does not fix the problem, I will park it again, and just pull the old block out.
Here's the thread about it, do you guys see anything I dont? (except the fram?)
04-09-2008, 12:49 AM
well, get the MAzdatrix replacement. 15 bux more than the stock OEM from Mazda. Had it not been for them having it in stock when I needed it I would have gone with the Mazdatrix version. Just make sure you have the NEW one ready when th eold one breaks again. 100K miles is a lot of miles.
04-09-2008, 12:27 PM
Ok, so I checked it today, the coolant is always lost, but it's not a TON of it, the rad always fills up pretty quick, and also the coolant is LOST pretty quick... like, 15 min of driving the thing goes off. At home for lunch, the upper hose was still cold, but then it got hot like it's supposed to. I noticed that my coolant reservouir has dark coolant in it, and there's like an oil looking thing on the surface. Also, system seemed to have quite a bit of pressure in it, so is it possible that the iron cracked or something, and it OVER pressurizing the system? My overflow bottle DID have a bit of extra coolant before the T stat opened, so...
Also, I'm going to go order the neck from Mazda, but is there any other place cheaper, that can get it to me ASAP? Advanced didnt seem to be able to order the part.
04-09-2008, 12:53 PM
I think mazdatrix has an aluminum one for the S5.
S4 has an aluminum one stock but its got arad cap cast into it, the m-trix one is just like the s5 only aluminum and cap-less.
04-09-2008, 02:04 PM
S4 necks and S5 necks are not interchangeable either. Its not just the rad cap that makes them different...
04-09-2008, 02:16 PM
the bolt pattern is different. 2 bolts vs. 3 bolts IIRC
04-09-2008, 04:15 PM
Damn, the aluminum one is $150!!!
And even the plastic one is $60!!!!
how much did you pay for yours? I thought it would be like $15 or so for a simple plastic part... geez!
04-09-2008, 04:19 PM
I paid $115 for one from the local mazda dealer last year. When mine took a crap I had no other choice since MAzda had it in stock. The mazdatrix one it only cost $125 + shipping but I couldn't wait for it to be shipped.
04-09-2008, 04:44 PM
Dude! Mine is $95 from the dealer!
Atkins sells them for $65 it seems....
Well, what about... getting some SS pipe with a 45 degree diameter, and making a flange, then brazing that together? I am in shop class right now, and it's possible!
04-09-2008, 04:47 PM
yeah, that's why i think you should spend the extra cash on a metal piece that won't break like the plastic/original FG ones.
If you have the tools then make one. Just check to make sure it's not flawed and will give you problems down the road..
04-09-2008, 08:30 PM
Mazdatrix one IS metal right?
04-09-2008, 08:40 PM
04-10-2008, 02:59 PM
dude max go with the metal one. i had the same problem a while back. i would drive like 20 min and my coolent was gone. it turned out to be the neck. got the metal replacement cuz a local fd owner made me ha. and i havent regreted it.
you ever going to get that other engine?
hey im tearing down my garage and building a new one so my suspension and 3rd gen turbo stuff has to go.
04-10-2008, 05:57 PM
wait, isnt S4 supposed to have a metal one stock? or was yours cracked?
And yes, I'm getting that other engine, just that I have like, almost NO cash ATM, so I'm gonna be selling some stuff...
04-10-2008, 10:08 PM
oh kool. what are you selling. its a rebuilt engine.
04-12-2008, 05:14 PM
Hey guys... so today I ground the coolant sensor, so it does not go mad, and drove my car around a bit, parked it for 2 hrs, and drove some more. The coolant gauge never went higher than 1/2 and since the buzzer didnt go off, it seems that it is NOT a bad wiring in the harness problem.
My question is: how much pressure is there supposed to be in the upper rad hose after the engine is shut down? Mine has a lot of pressure in it. Is it possible that my coolant leak may be a cracked housing and the combustion pressure overpressurizes the coolant system?
also, my car smokes a blue-ish/ white ish color when I first start it up, and id does so for 5min or so until it warms up. How heavy should this smoke be if it sat for like a week? I had it coming out of there like a stove pipe!
04-12-2008, 05:22 PM
uhoh. White smoke like you describe = bad coolant seals. Take a pic/vid at the next startup.
04-12-2008, 06:57 PM
Well, it stops after it warms up... but it smokes like it DOES have bad coolant seals...lol
04-12-2008, 07:17 PM
that means that your coolant seals have expanded once they reach operating temps. As the car cools down the coolant seals contract and the rip/tear in the seal allows coolant to seep into the chamber that eventually becomes that sweet smelling white smoke.
Must have overheated badly enough to damage the seals.
04-12-2008, 10:26 PM
Well, then that other engine is coming in ASAP!
The thing is, this one, even with 140K still runs like a fresh inmate from the showers.... so maybe it go a rebuild some time during those 140K? But then again, maybe I just dont know how it SHOULD run? I drove an S4 vert, and it felt way slower, and only had like, 115K on it.
04-13-2008, 04:00 AM
well you overheated it and killed the seals. It will run fine until the crack/tear gets big enough to not close at operating temps and then your gonna be burning steam at all times.
04-13-2008, 10:51 PM
/\ I kinda figured that, lol.
Ok, here is another problem, my car will NOT start when hot! IT used to, when I bought it, but now it just doesnt go. I think that the 141K, leaking injectors (not 100% but pretty damn shure considering that I need to put the pedal every time I start it cold) andf the fact that I ran a can of sea foam through contributed to this. (yes, I changed the plugs after) I swear to god, when I put the other engine in there, EVERYTHING that isnt nescessary for it to run is coming out and going in the garbage!
I'm sick of CSA, BAC, and the rest of that stupid, over-engineered crap that mazda put in there for almost no reason.
04-13-2008, 10:54 PM
Sounds like you have a flooding issue. I have a fuel pump switch installed under the drivers seat to deal with this.
04-14-2008, 10:31 AM
dude theres an s5 vert engine for sale in danville. bob smiths auto. you should look at it cuz its pretty cheap and it has everything.
04-14-2008, 10:21 PM
really? I'm gonna call. Transmission too? Or just engine?
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