Hey Guys,

I'm looking for suggestions. My engine typically runs around 88-89 degrees Celcius in 90+ Ambient (HIGH HUMIDITY) days here in Atlanta, GA. Stop and go traffic will let me temps build to about 90-91. This is with the Air Conditioning off.

With the Air on, in highway driving, or stop and go, my temps climb to 97 degrees or higher. At this point, I turn the air off and the windows down. Consequently, most of my driving I do with the windows down, never turning on the A/C.

I have the standard reliability/cooling mods, please see signature for detail. Is there anything else I can do do assist in cooling?

At this point, my options are to purchase a daily driver, upgrade the FD to a reliable cooling point, or sell the FD. I love driving this thing and have only had it for 9 months. I obviously do not want to get rid of it.

I daily drive the car, and it has been amazing, although in summer heat, I smell like exhaust everywhere I go. I'm sure when I roll out to customers in a suit, smelling like exhaust, it brings a laugh.

Fortunately the A/C still blows cool and seems healthy. Other than the fact that my temps go through the roof, everything seems to be fine.

Am I being overcautious because of all the hype I read on the boards?

Looking for suggestions..

 

Thats typical. 97 C is nothing to get worried about. I turn mine off when it hits about 100 C.

 

My first thought is to double check your cooling fans. I'm having a similar problem currently but I know its because my driver side one is a little lazy, whether because of wiring or the motor itself.

Maybe its time for new coolant?

 

Coolant is good, fans are good.

Per Zero-banger's comment, I think this is typical. I'm just wondering if there is anything I can do that might improve the cooling slightly. I.E. battery relocation, or paying special attention to duct work to make sure everything is sealed up nicely, pointing cold air in the right directions.

 

I got a rally racer I can sell you

 

Check the T-stat and fan operation, if they are OK then 97C wouldn't worry me.

 

Few things you might want to check or try:
New thermostat or modify the one you have(add another hole), change water to coolant ratio for summer(70/30 + water wetter). Get a vented hood.
Having a PFC, borrow a Datalogit and change the temp that the fans come on with and without A/C.
Change the five blade fan to a 4 blade fan.
These are not the majic cure for our cars, but every little thing counts.
If all of the above don't work to improve the temps, then get a daily driver or buy lots of Fabreeze.

 

What happened to auto-x'ing the rally racer? You don't want to sell that thing already? How's project FD coming along?

I'm going to hunker down. Staying with the FD. It's been good to me and I'll be good to it. If she wants to drive, she can deal with hot and exhaust, and I'll roll in the new wanna be yuppy soccer-mom-mobile.

I'll check the T-stat, fans seem to be good. Dubulup wired up a fan-mod for me, which helped a lot. Temps I posted earlier in this thread were POST fan mod.

I'm already down with the fabreze! It actually helps the car. Now, car doesn't smell like exhaust (I actually keep it clean). It's my Body and clothes that smell like it! Nothing a little hand wash and extra does of cologne can't cure.

 

I would look into increasing your coolant system pressure, and running more water less antifreeze. If I'm not mistaken, 93's originally came with 13lb pressure caps, then were downgraded to 10lb caps after a few people had problems with hoses and AST's that didn't work with the pressure. What is your water/antifreeze mix right now?

Higher-pressure systems will be able to run safely at higher temperatures without boiling, and water has much better heat absorption properties than antifreeze.

When increasing the pressure, be sure all your hoses and clamps are in good condition. Personally I would replace the hoses and clamps to be absolutely sure.

100 C is the boiling point for straight water, under no additional pressure. Your coolant will not boil at 100 C. The stock ECU settings will turn on the cooling fans at 110 C. I'm not sure if these settings were with the original 13lb cooling system in mind, or the post-recall 10lb system. I would put my money that the fan turn-on temp settings were not updated when the coolant pressure was decreased to 10lb. I wonder how the newer (99+) cars cooling system works, does it run at 10lb or 13?

-s-

 

Mine usually jumps about 5 degrees C when the air conditioning is running. Considering the AC condensor is right in front of the radiator and the fact the engine has to run a little harder what you're seeing is perfectly normal.

 

I run 100C everyday here in FL. In real bad stop and go, I have seen 108C. I wouldn't worry about it, even 108 isn't that close to how hot the system was designed to run. Granted, cooler would be better, but you aren't going to kill your engine at those temps.

 

I see you've got a midpipe. I remember reading somewhere that a leak in the bodywork or weather seals around the rear window can allow some of that unfiltered exhaust back in, resulting in your smell problem. Have you considered resinstalling a CAT? That should clean up the smell of your exhaust, I would think.

 

97c is not to hot, but for cooler ...

make sure all 4 sides of koyo are sealed. all air from front opening must go thru rad, intercooler, or into inatke. also consider stock pulleys, for higher coolant flow at modest/low rpms.

 

if my car is idling w/ the A/C on and the fans manually switched on, my temps can get up to 106C...but coasting with the A/C on the car usually runs around 93C...but while idling w/ the A/C on, my RPMs would bounce between 900 and 1200-1500...i've heard that manually adjusting the idle could fix this problem, but i haven't tried it yet.

 

Well, your idle is bouncing because it is compensating for the AC going on and off. Look at my AC cycling on/off thread. Sounds like you have the same thing I have.

 

You've identified the primary reason that I've considered selling my RX-7 on numerous occasions. It frustrates me to no end that I cannot drive my car the entire distance from work to home (about 15 miles) on a hot summer day with the A/C on without my temps climbing up over 100C. I've always wondered why, in my 94 Maxima daily driver with 164,000 miles, I can sit idle all day long with the A/C on and have no fear of overheating.

Like you, I've upgraded most components of the cooling system, set the Datalogit to turn the fans on sooner, wired up the fan mod to control them whenever I want, 16 psi cap, etc, etc. The only thing I'm missing is major sealing of the radiator and a new thermostat. I've wondered if the relationship between oil cooling and water temps is strong enough to make a difference, as I only have a single oil cooler.

It's a shame that we have to be uncomfortable to enjoy this car year-round.

 

Read my new thread regarding my test drive of a 330 coupe. I recommend you do the same, then you'll realize how much you love your FD. New Thermostat, battery relocation, and some extra special attention to the "ducting" for IC, Radiator are in order.

https://www.rx7club.com/showthread.p...hreadid=327215

I am also under the impression another oil cooler would assist.

 

Hitting 100°C is not a problem considering 125°C is the boiling point of a 50/50 antifreeze mix under about 10psi of pressure. If I remember right the factory shop manual states that 105°C is the normal operating temperature with the A/C running. As long as the coolant doesn't boil you're not going to hurt the motor and you have a ways to go before that happens.

 

Your right, hitting 100C probably isn't that big of a deal, but I'm certain that the temp would continue to rise if I didn't do something about it.

Also, and I have no data to back this up, I believe that you will cook a coolant seal before your mixture boils. The highest water temp I have ever seen on my Power FC is 114, or 237F. My car has never "over-heated" in the traditional sense (forced to the side of the road with steam everywhere), but it has run very hot several times, and I am currently experiencing the symptoms of coolant seal failure.

 

Someone mentioned a vented hood. I was considering one for the same reasons and to get more air through my stock mount large custom intercooler. Does anyone have any real world experience or numbers to share (temps) with one of the vented hoods?

 

Not much you can do in my opinion. You've already upgraded the radiator to a Koyo. You don't have a FMIC blocking the radiator so airflow is good enough. I don't think changing out the coolant will help, unless your low on coolant or it is very very old. A vented hood would actually help a lot. Especially when you are done driving it can remove a lot of underhood heat, to keep the car from heating up even more after its done driving.

One thing I was thinking of for my own personal FD was to add a Nitrous intercooler sprayer for the radiator, sounds a bit funny but yes I was thinking that.

Maybe water misting on the radiator might help.

 

A few of the autocrossers in my region who own heat-sensitive cars mist their radiator with a water-sprayer between runs. This would be pretty easy to implement, I plan on trying it out this summer after installing a good temp gauge.

-s-

 

I have the same problem, except I don't have a water temperature gauge. I live in El Paso, TX, so you can imagine the heat outside. I always arrive at any destination soaked in sweat.

I upgraded to a Fluidyne and it has helped to maintain the needle in the 9 O'clock position for a longer time. Before I would overheat from just a drive to tthe store, and the store is only about 3 miles away. I hardly boost on this heat conditions.

QUESTION: Are there any aftermarket fans (example, Spal) that can fit nicely with the stock front mount? No fitting issues that is. I wouldn't mind waiting longer on power mods just as long as I can turn on the AC and be cool. Thinner faster blades. BTW, I have a 65% water 35% antifreeze mix. It helped a lot too.


PS: I cannnot think of even going through the International Bridge with my Rx-7. Lines are horrible at midday.

 

From the consensus of this board, aftermarket fans are no good. The best advice seems to be is upgrade all the blades to 4 blade fans. The theory is that the OEM fans flow more than aftermarket fans, but there isn't any real proof.

I think getting a vented hood will help a lot. I think the Scoot hood would be perfect, because it will take in air and vent air. But to some it may look a bit overboard. However, I think its well worth it if its functional.

 

yea check your cooling fan. They might be blowing slower than new.