Not sure how good I am at searching, because I couldn't find an answer BUt what do you guys normally see for water temps and at what point is it overheating?

This summer I have seen 185-190, but the past couple days it went up and I even hit 210f. I then acked off immediately, went home flushed the coolant and changed the oil. Now I need to go get an OEM T-stat.

My question is what is an unsafe temp for the car for any sort of sustained driving>? mine is an NA.

 

I had an old RX-7 that ran at 210 all the time. It's probably not good for the engine, but you can do it for months and months no problem. I quickly learned precisely what the temp gauge meant. 1/4 is normal, 3/4 is still okay (210), 7/8 is overheat. That's an s4. For S5 1/2 is normal, and it doesn't raise very much before overheat. And yeah, an OEM t-stat is the most common cause of a temp problem, I think. I didn't know that on my last RX-7. My dad thought it was running "too cold", so he replaced the t-stat with a cheap auto-store one .

 

210F is nothing to be afraid of.
My FC sees 230F almost weekly cause a friend live on a big hill! :P


-Ted

 

200F is nothing to be afraid of
210F is still not too bad in hot weather
220F anything above this i try to stay out of higher boost levels
230F i tend to start to worry and will limp the car as gingerly to get where i'm going keeping it out of boost
240F is pretty damn hot
250F you better hope you have AAA, your coolant seals will let go at about 255F

 

you guys are crazy!! I had a heart attack anytime I saw 200 in my turbo FB...

 

We've had our FC track car hitting 250F on the water gauge at Thunderhill, and it was still running.
I like to back up my data with real-world experience.


-Ted

 

How much does it depend on where you put the sensor?

 

205-210 all day in my 91 NA track car. This was at an HPDE at VIR earlier in May. We were double stinting the car, so it didn't get a whole lot of rest. I'm running about 90/10 water/coolant with water wetter and the stock 190 degree thermostat.

The FD will see 220+ occasionally when idling around town during the summer, but I like to see it back down to 180-190 once I get moving for a while (highway). I'm running about 70/30 water/coolant.

Just some data points.

-bill

 

Some. The most common places to put the sensor are either in-line in the upper radiator hose, or else drilling and tapping the back of the waterpump housing. Readings from either of these two locations are probably he most accurate.

For my FD I actually put the sender in the line I made to bypass the throttle-body coolant hose. It seems to work well, but it's almost certainly a few degrees cooler than what's going into the top of the radiator.

-bill

 

Agreed.
We aim to put the sensor (or tap in case of a mechnical gauge) under the thermostat, in the water pump housing.


-Ted

 

if you run a line to bypass the coolant thats supposed to flow thru the TB, arent you effectively short-circuiting the cooling flow around the housings, making them run hotter than they would otherwise?

 

I've got mine near the hose near the stock S5 temp sensor location. I believe it's accurate. The S5 gauge never moves but the autometer is not the same today I was running about 205 with AC on at 70 mph. I'm going to buy a new thermostat. I'm not sure when last it was changed an for $20 and a glimpse of a few Ferraris I can't go wrong.

I just want to get this thing going great as I am likely going to try to get to the track for the midwest rotary meeting in august.

 

that's where I tapped mine in

 

Interesting. Just wondering, how do you know at 255 the coolant seals will let go? Experience?

 

What I'd like to know is how to read the stock temp gauge. Halfway should be... what? 200 deg F? 190?

I forgot I should be more specific. This is for an '87 TII. I remember reading SOMEWHERE that the NA's and TII's run at different temps, but I don't remember if they have different gauges...

 

Ted: everything you just stated about temps goes against everything I've learned. From my experience I've destroyed motors with stock seals at like 215*F. This was in 95*F Orlando heat. Stock mazda seals. So now I'm confused. WOW!

My current set up, I'm doing my best to keep the temps around 190* under loaded boost conditions with an ambient air temp of around 90-95* humidity does play a factor. So far the bigger radiator, and a lower temp thermostat seems to be working well.

 

I recomend u check out my thread

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/why-you-need-change-your-coolant-664175/

 

My clutch fan **** on me in my T2 and I pegged my aftermarket temp gauge (over 250) and my coolant seals were fine. They weren't OEM though.

I consider over 210 hot. On my n/a at tail of the dragon i would tach 6000 for 20 minutes at a time and it never went over 210. In my T2 I went to VIR Holiday Laps in the dead of winter and never saw over 185 even continuously boosting it for 20-25 minutes

 

Nope all the coolant issues I had, the car had a Mazda Stat, and fresh coolant. flushed radiator....etc. After that one time that it went to 215*F it got worse, and harder to start, then slowly started eating coolant. Soon there after it would over heat on the HWY, but not around town. I had and still have a FMIC. 75% of rotary owners in the FL area say it's too hot. Even some of the Guys from PR.

 

Too hot meaning anything over 210*F. So I promised myself to make a system to keep the temp down to under 190* Right now cruising around town, my water temps are around 175*F

 

I would take his word for it, Ben knows what he's talking about

 

Don't.
You really need a good, aftermarket gauge for this.


-Ted

 

That is not a constant load.
Once the car started to get that hot, we headed into the pits to let it cool down.
Ambients were 100F+!
Track temps were about 115F!

If we're talking constant load, I wouldn't let it stay over 230F to 235F.
You can literally smell the engine burning when you hit temps like that - at least my engine does it.

The engine should take intermittent jaunts up to 250F, but don't make it a habit!


I just find it funny how many people are so paranoid about getting the temps just a little bit hot.
The thermostat is rated about 180F.
It doesn't fully open until about 195F.
The stock viscous fan doesn't lock until about 220F.
The stock electric fan doesn't kick in until 225F (FSM might state lower, but my water temp gauge told me it kicks in at 225F).

Don't forget, I'm in Hawaii.
Ambients during the day are usually in the 80's.
Right now it's hovering right under 90F.
Nights are typically in the 70's and sometimes dip into the 60's.

I run a big rad too, and it helps a lot.
I think this is a must for any FC.


-Ted

 

hey are the adapters for coolant temp sensors that go in teh upper radiator hose accurate? if that was confusing, i am talking about one of these:

http://www.rallysportdirect.com/shop...er-p-2757.html

 

I would never use one of those things, because...it's after the thermostat.
If thermostat sticks close (which is a good possibility), you will very little warning you're too hot.


-Ted