OK, someone help me out here.

I just got my FD.

I started driving it and I notice sometimes during slow driving or after driving and coming to a stop the tempature starts to climb. If I sit long enough it goes down. Or if I just drive it off, it goes down real fast.

Here is the odd part... if I turn on the A/C it stays perfect stable all the time.

I'm thinking 1 of two things... I have a fan out and my A/C fan helps whatever problem I have.

Or there is a bubble of in the coolant system and it needs to be burped out.

Any thoughts?

 

Turning on the A/C makes your cooling fans come on. It may be that your fans don't normally turn themselves on. That could be do to a bad relay, the thermosensor being disconnected or bad, or any number of other things. One important thing to remember is that the stock temp gauge is a peice of ****. If it is rising then your car is WAY hotter than normal. When the stock gauge starts to move the car may be at 230 degrees. Always keep your A/C on until you figure out the problem. Burping the cooling system is pretty easy, just wait till it cools down, and fill it up.

 

While you're at it, you might consider the fan modification:

http://rx7.voodoobox.net/howto/fanswitch/fanswitch.html

 

Ummmm is it me or does that sound completely normal?

Slow Driving or Being Stopped = no air flow, hence an increase in temperature

Driving = air flow through the radiator, hence better cooling

Sitting still long enough = temperatures rise, and eventually stops when your fans kick on

Turning on A/C = turns fans on automatically, and as well like turning on your parking lights draws more power from the car causing the fan kick on temperature to be lowered

Everything your saying is normal

I'm guessing you have an aftermarket guage cause the stock one doesn't really move, it only has three temperatures: cold, normal, your fucked

 

If he's running an aftermarket gauge then, yes that would be normal. But if he's looking at the stock gauge then that is a problem, because it shouldn't come off the half mark until your engine is hot enough to cook a steak on.

 

Amen.

I have a Water Temp Gauge, the Power FC monitoring the water temp, and the Stock gauge and I can personally attest that my stock gauge does not flinch until past 115 deg Celsius.

 

my fans kick in why my temp gauge shows 240, the stock gauge doesnt even move at that point, i let it go to 240 once since i owned the car just to see when the fans come on. i might have a bad temp sensor. i have a the fans wired to a switch that i hit to On when i start reaching 210 on the gauge.

 

It is the stock gauge, I haven't had it long enough to get any better gauges. I'm still deciding which to order.

And yes the stock gauge would sit at half normally. Would climb to maybe half way between "half" and yellow.... I'd drive, or sit long enough and it would just fall back down.

This process would happen in the span of like 3 minutes. Real quick. If the engine was overheating I would assume it would "stay hot".

Plus I wasn't even boosting it, or driving it beyond 3k rpm.

If this is a doomsday indication, well the engine and turbos are under warranty... but it seems more like an indicator problem or something to me.

Any ideas for a first troubleshooting step to determine root cause?

 

Seems to me you need a better diagnostic tool than the stock gauge. Any linear gauge is better, even a cheap one.

Personally, I wouldn't drive my car if I thought it might cause damage. O-ring failures are far too common and far too expensive to fix.

You might just need a thermostat...

 

Yea I was orginally just gonna get an a/f and boost gauge, but I think I'm gonna ditch the a/f gauge and get a temp gauge instead. Go with a 3 pillar and get all 3.

I'm not going to drive it on a regular basis until i get it figured out... if I do tho, the a/c seems to work fine.

How should I check the thermostat?

 

Actaully any electrical load will make the fans come on sooner than they usually do..so just drive around with your parking lights on and that will do the trick as well..

It's strange that you see your stock gauge shifting beyond the normal half way point..I've had my FD for a little while and drove it without a Boost and Temp gauge, and once the stock gauge reached it's mid point, it never budged regardless of me driving or sitting at a traffic light.

With the aftermarket temp gauge, I can actually see the temp moving around in quite a large range..from like 170 deg F to 210-220 deg F while the stock gauge just sits there..

So definitely get a temp gauge pronto..

I don't believe anyone makes a 3 pod A-pillar gauge pod..2 pod is the best you can do..you can maybe buy the 2 pod and 2 pod and fuse them together.

I currently run a couple of Defi-link Boost and Temp gauges in the Autometer dual-gauge pod..when I need a couple more gauges, I will go with the Tri-Power center speaker pod.

 

So in other words, from what everyone is saying, if the stock gauge actually moves, something is probably somewhere near the tempature of the sun...

Lovely.

What I don't get is why it would go back down so easily. If it was that hot, I would think it would take at least more than driving 100 yards, or sitting long enough (note a/c off) and it dropping. It would stay hot right?

Blarg, this is driving me nuts.

Oh one more thing, is it normal for the center console (shifter area) to get so damn warm?

Is my car just a fast BBQ'er waiting to explode?

Am I just being paranoid and should shut the hell up till I get a better temp gauge?

Is the sky blue?

 

That is not necessarily true. *If* the previous owner did the "stock gauge linearization" mod, then the gauge would move to show the temperature increases and decreases.

Do you know everything that was done to the car before you bought it?

Honestly, the only *real* way to see what's going on is to get some sort of aftermarket temp gauge so you can see "exactly" what temperatures your car is hitting.

 

Yes, and I'm pretty sure that wasn't done. I need to call and double check tho.

I just ordered an autometer water temp guage. Thanks for your help!

BTW, what is the acceptable range of tempatures and what is "too hot" for when I get it.

 

Keep in mind that the gauge won't look any different if that mod was done, it will only react differently.

As for safe temps, there are tons of threads around on that. People seem to have different ideas on that so I'm not going to offer an opinion. However, I believe the stock ECU doesn't turn the fans on until around 220F. With electrical load increased (like turning on the parking lights), the fans come on around 210F.

 

My center console got really warm until I got a downpipe. That pre-cat throws off a tremendous amout of heat.

 

Ok, I found out the stock temp gauge mod was NOT done. So my car really was overheating.

Great........

I have a autometer water temp gauge en route, but it will take a few days obviously.

Any suggestions on what I should check in the meantime?

 

I would change the thermostat. If you just bought the car, you don't know the last time it was changed anyway.

Thoroughly flush and change the antifreeze.

 

I've got the stock precat and my center console (shifter area) does indeed get warm..so that, at least, is normal..

And as suggested a while back..you might as well do the fan mod while you're dealing with the cooling aspects of your car..

 

Yea, I'm gonna check out the fan mod.

But its kind of pointless unless I can figure out wether my car is overheating normally. I shouldn't have to run the fans extra, it should work normally.

The car wasn't driven a lot before it was sold to me so I still gotta do some research before I figure out what it is. First thing is to wait for a real temp gauge to arrive so I can see what the real story is.

 

What type of coolant are you using? Pineapple racing is comfortable running their engines as high as the 260s using Evan's at 0psi.

I'm running Evan's and recently watched in fear as my stock gauge went halfway between the center and the top white line. Then it went back down. I don't know how hot that was, but I'm not really worried. I'm losing no coolant and the Evan's keeps the coolant system safe from bursting (at 0psi) and you wouldn't get any localized boiling until 370+ (that's where Evan's boils, but I'm sure that would be "hard" on the engine).

Damage from overheating occurs when the coolant fails. That happens because a) it boils or b) the system bursts and coolant fluid exits that car. At that point the engine temps rise exponentially fast as nothing but air outside the engine is absorbing the excess heat. At that point things start warping (rotor housing) and seals quickly give way.

If your coolant did boil, there could have been a lot of localized heat. That could cause warping in the housing. The fact that the temp quickly reduced is good though (when mine went up it wouldn't come back down very fast, although it did on the interstate).

Just my thoughts.

 

Do you have an aftermarket radiator?

Either way, you could have clogging in the radiator which would reduce the flow and efficiency of the cooling.

Difficult to diagnose, but you could have a rad. shop boil it out for you.

 

Actually I do. Its a koyo hp radiator with a koyo metal overflow....

Should I flush it?

 

It can't hurt. I would consider using a cleanser solution that you can get at any auto parts store. Then flush with distilled water a couple of times to clean it all out. Then fill up with the coolant of your choice.

If you switch to Evan's, don't forget to flush with Sierra before putting in the Evan's.

 

Replacing the thermosensor with a Miata one can't hurt either