Recentlyconverted

Hey guys,

I was in dead stop traffic on friday for a while, and my temps just kept getting higher and higher and higher (oil and water temps got to about 240F before I was able to start moving again and cool off. The car ran like crap for a bit (the idle dropped down to like 650 rpm and would fluctuate from like 600 to 750 rpm), but as soon as I got to where I was goin, I popped the hood and let the fans run, then restarted the car to let the cooled fluid in the radiator circulate into the engine (car still ran like crap but a little better) , shut the car down again, let the fans run again and then turned the car on again to circulate the rad fluid (this time the car ran well). The car's been runnin fine since yesterday.

I was curious though, I did a search and couldn't find anything, but do any of you guys know what critical temperature is for the 3rd gen? i.e. what is overheat temp (my stock temp sensor never went all the way up, and my coolant buzzer never went off). ??

My aftermarket temp sensors go from 0-250, anyone know when I should absolutely be shutting the car off and what temp is considered overheat temp?

Madmax670

murphy's law

widebody2

I'm curious of this too and don't really feel like searching. Anyone know it in celsius?

skunks

for my fc, i shut her off at anything over 230; for my fd, i shut her off after anything over 210. then again i dont race my cars (there is no racing in Hawaii ).

yes up to and perhaps over 230 a bit is probally fine when your constantly tracking your car and if your not boiling over (or so i have heard) but personnaly I don't let it get anywhere near that in my fd. personnaly, i think that if your just driving around normally with your fans on, there should be no reason why your car is hotter then 210 unless your possibly in 110+ degree weather.


BTW: where is your watertemp sensor? also did you have your fans on?

rynberg

There is something wrong with your coolant system. Possible causes are a bad t-stat, fans not coming on at proper temp, air in the system, etc.

On the standard 13 psi system, you are ok up to 235 or so, but I certainly wouldn't push it past that. The actual point will be determined by your water/coolant mixture and the pressure of your system.

As far as the celcius numbers, dude, it's called www.onlineconversion.com ....

Recentlyconverted

what makes you think there might be something wrong with the 7? this is my first fd so I'm not aware of how the car is supposed to act at idle. how high should the temps go when at idle (keep in mind this was in 50F weather) before it levels off?

turbojeff

iTrader: (30)

In 50F weather your car should go up to about 221F then the fans will turn on. If yours got up to 240F in that cold of weather you have a bad T-stat, radiator or fan(s).

I could see the car getting up to 230F which is really hotter than you should run them on a hot day with lots of load.

Recentlyconverted

yeah, I guess you're right. might be the t-stat. the fans do some on at about 220 F, but they will turn off after about 30-40 seconds or so, they will then come on again for 30-40 seconds every 5-7 minutes or so. is this right? should the fans stay on?

Recentlyconverted

oh, and i also have a water/coolant mix of 60water/40coolant. this should br good right?

skunks

if i were you, id do the fan mod to control the fans manually thru grounding the relays. i keep my fans on at least low when my car is on but thats just me. i keep an average temp of 180 degrees.

zullo

The stock fans don't even turn on til 221F which is dangerously close to overheating. If your thermostat is sticking or you have some other issue, fans coming on at 221 may not be able to compensate.

Don't think that your car should run at 180F like skunks. He is simply running fans full time which holds it at thermostat temps. The car, by design, should run between 180 and 220 something, the range between when the thermostat opens and when the fans kick on.

A short-term "fix" if you don't need your A/C is to pull the A/C relay (in box in front of air box). Then, when you turn your A/C on it will run the cooling fans instead. Run the fans manually when you see temps around 190. If it takes care of the problem, go get a Miata 195F thermoswitch (or FC thermoswitch, see recent thread by Dale Clark), replace the stock one, plug your A/C relay back in, and your problem may be solved.

Oh, and definitely replace the thermostat while you've got things apart. Cheap insurance.

Outkast

Mine usually never goes over 90 C and normally runs at 88 C when driving hard for a long time and with the fans on through the a/c being on

technonovice

230 deg F is 110 deg C

ratincat

heres a link to a temp converter

http://www.parker.com/o-ring/static/...mp_convert.htm

Recentlyconverted

wow, thanks guys, this really helps a lot. I'm gonna try to pull the ac fuse and then see what happens the next time I'm in traffic. the problems seems to only happen when I'm stuck in traffic, if I'm doing highway driving (which is about 80% of my daily driving) my water tamps stay at about 180F and with the cold weather and the dual coolers my oil stays at about 150F.

But that brings up one question though, with the stock setup on the 7, when you hit about 220F, are the fans suppoed to stay on or is it supposed to shut off after less than a minute? my fans will come on at 220F, but they'll shut off after about 40 seconds or so. is it supposed to do this?

Recentlyconverted

ok, so I just went outside and checked the intervals for the cooling of the car. with the ac on, the fans would come on for about 7-8 seconds, then shut off and remain shut off for about 30 seconds, then come on for another 7-8 seconds, then shut off and remain off for 30 seconds, then turn on again and keeps cycling that way (8 seconds on, 30 seconds off, is this rhythm right??), I turned on the ac at about 170F, and the temps slowly kept rising past 180F, and I shut down at about 185F.


I tried pulling the fuse (I pulled the one that was right behind the battery (i couldn't find any fuses in front of the air box, should they be under the plastic cover in front of the air box???) and the engine ran ok for a while, but after a few minutes my engine rpm started to fluctuate violently and I shut off immediately. I put the fuse bacn in and the car ran ok again.

2FAST7S

In my opinion, and from asking rotary builders the temps at which the stock fans turn on are a bit high. Compound that with the size of the stock rad and you have an easy way to cook your engine. I think the closer to 180(thermostat opening temp) you maintain your engine the better off you are for both efficiency and reiliability.
In your case, its borderline...i've heard of our engines hitting 250 and not developing any problems...then again i'd shut mine off or at least back off once it gets to about 230 just to be safe!!!
Where are you taking temp readings from??? how acurate is your sender/gauge?
My advise to you is, change the thermostat! Its about 15 bucks and easy to change! do the fan mod, another easy fix! If you have the $$$ go with an aftermarket rad that will not overheat on you on a 50 degree day in traffic!!!!(if its bad now thats cold, whats it gonna be like in summer???) If you have PFC change the temps at which the stock fans will kick on!
Whatever you do, dont let it get that hot again.....you might not be so lucky next time!

Recentlyconverted

gotcha, will look into getting a thermostat repalcement and am looking into getting a PFC anyways, maybe this should be my justification to get one. but then if I get a PFC and turn the temp at which the fans turn on to 180, that kills the need for an aftermarket thermoswitch, right? (what exactly does the thermoswitch do? does it turn the flow of the fluid on/off, or does it turn the fans on/off?)

user 9348703

110C is bad
120C is new engine time

Recentlyconverted

oh, any by the way guys, I never pushed the engine after it hit 230F, basically i kept it in the 2-3rpm range and then stayed in neutral down a winding hill for about a minute (in that minute the temps dropped from 220 to like 190). oh, and my aftermarket temp sensor is set up to take the reading of the fluid directly leaving the engine block

zullo

The thermoswitch triggers the fans. I've no idea how it interacts with PFC settings or fan relays however. Maybe someone can clear that up.

As far as the quick A/C relay fix I mentioned earlier - the A/C relay is in the plastic relay box in front of the stock airbox. Don't pull any fuses.

adam c

iTrader: (2)

Your car should not get to 240 degrees on a 50 degree day. Check your fan relays on the passenger side fender. It may be that one or more of them have become unplugged. This would mean that only one of your fans is working. Here's a link to an easy fan mod:

http://www.scuderiaciriani.com/rx7/fan_mod.html

I like to turn on the fans when I am in traffic to keep the temps down. I also like to turn them on a few minutes before I reach my destination. That way the engine is pretty cool when I shut it down.

zmarko

Exactly what I do.

Twinturbo522

what temps do you guys see driving in the city (3rd gens).. My temps stay at 100C?????

user 9348703

My temps are always between 89-95c city driving, my temps never go above 95c, but on the freeway they run colder like 87c, and usually stay there..