greasycheeseman

this has been happening for a few weeks...

on my 88n/a i have disabled the aws, egr and cats... replaced spark plugs, replaced thermostat with one from mazdatrix... i bought the thermal pellet mod from atkins rotary, but havent been able to put it in due to the fact i cannot get my eccentric shaft front bolt out. i replaced spark plugs, and have replaced the coolant with 50/50 mix antifreeze... now then the problem...

every time i drive my seven... it starts to overheat... i cant take it any more, and the wife says no more money can be spent on my car, and i agree with her, i have bought many replacement parts for the interior, and all the stuf mentioned above, costing alot for those who have just got themselves married. the needle starts going up very slowly if sitting, and it goes up even quicker if im driving.... the only way to cool it down is to turn it off and let it sit for hours, or it will cool down if i drive for a while at highway speeds steadily. i dont know what else to try to work on, and sadly, if i cant get it working soon, i will have to sell the car(i love it, and its my daily driver) i have changed the oil religiously at about every 2k since i got it, and the radiator caps are good... so i dont know now.... radiator? water pump?? i hope its something easily and cheap, cause if its not, my car goes by by and i have to search for something more reliable.... thanks for the help

J-Rat

iTrader: (2)

Okay, there are SEVERAL HUNDRED threads covering this, and even a web site, courtesy of our beloved moderator Aaron Cake. Lets see if I can find it...

Here it is:

http://www.aaroncake.net/rx-7/cooling.htm

Good luck! I personally think your clutch fan went bye bye.

Jarrett

BigTone

You can replace your water pump pretty easily and cheaply. You can buy a new OEM radiator for about 200 shipped. The only other thing could be the fan clutch.

greasycheeseman

no flames please.. i have searched and read MANY articles and posts on this subject, and have read aaron's writeup on cooling. maybe i should just go to an e-fan, but i worried about my electrical system too much for that, cause its kinda crapy...

BigTone

I am moving on to a fiero fan, as for electrical system, you should be fine as long as you hook the fan directly to the battery. Correct me if I am wrong.

J-Rat

iTrader: (2)

Who is flaming? If you took my post that way, then I am sorry, I wasnt trying to flame.

You can test your clutch fan to see if it is really not working. Just get the motor hot, and see how much air it pulls. If its not pulling alot of air, then its probably bad. Generally speaking, when water pumps fail, there is a "weep hole" that starts leaking. So I think you may not have a bad pump. Also, have you bled all the air out of the system?

SureShot

Sureshot’s Overheating – check list
1) Replace the thermostat. Make sure it fits. The spring loaded disc under the stat valve must close the bypass port, or guess what?
2) Replace the radiator cap. Low pressure = steam bubbles = spit out coolant.
3) Look for leaks. (same symptoms as #2) Some can be very hard to find. You may have to pressure test it. A common failure spot is the 3/8” coolant line that runs from the top of the rear housing (under the intake runners) to the throttle body, to the BAC, to the water pump. Another one is the heater hose under the oil filter.
4) The fan clutch will slowly start slipping as it ages. The fan should pull really hard up to about 4k when the motor is hot. It should maintain about 4k as the motor revs higher. Sometimes you can get more life from it by bending outward the bi-metal strip on the front of the fan clutch. The cut-in for the series 4 fan clutch is gradual – it pulls some even when cold. The series 5 fan clutch is more on/off.


Banzaitoyota’s checklist
1.Are the Oil Cooler fins clear of debris and clean?
2.Does the Oil Cooler thermostat function properly?
3.Are the Radiator Fins clean of debris?
4.Is the Stock Bottom shroud still in place?
5.Are you running a Dual Belt Pulley on the Alt?
6.Did you install a NEW Water Pump when you installed the engine?
7.Is the bottom hose collapsing under load?
8.Did you have the Radiator and Oil Cooler cleaned and Flushed when installing the rebuild ( AS required by MOST REPUTABLE REBUILDERS)?
9. Have you verified water temps with a real gauge instead of the sock POS?
10. What ratio Coolant to Water are you running?
11. Are you running a new STOCK MAZDA OEM thermostat?
12. Mazda Rad Caps?
13. Stock Fan Shroud installed ( For those of you running stock Mechanical Fan)
14. Electric Fan users: Do you have a Shroud installed at all. Most installations only draw air directly across ~60% of the available core surface area.
15. are the stock deflectors installed around the relays forward of the Radiator Core Support?
16. If 15 is a no: Do you have an plate mounted across the support to direct air-flow?
17. Install a spring in the lower rad hose to keep it from collapsing at high RPM

J-Rat

iTrader: (2)

You know what I saw somebody do to the stock clutch fan? They friggin wired it up with a coat hanger, so it was locked all the time. Ghetto, yet effective in a pinch.

g_dripht-alex

in my 92 s13(240sx) i had some stupid overheating problems as well that no matter what i did it would overheat like crazy...heh and what do you know it was my clutch fan...problem solved...wish i would have known thatbeforei did the thermo to.

Rob500

Simple stuff first. You said you did the Rad Cap. Good. Check the Thermostat and Fan Clutch. You can get your Radiator cleaned at a rad shop. You don't necessarily have to replace it. An e-fan mod will not cure an overheating problem.

Rob

SureShot

Unless the fan clutch (~$180) is the actual problem.

My NA had a used fan from a Ford Tarus $10
Fixed setting thermostat switch $21
Cool RX-7.. Priceless

greasycheeseman

i have replaced the thermostat, but i havent "checked" the clutch fan... it looked like it was working though, but ill get into it. i heard that locking it was bad... like it screwed up airflow over 40mph or something...

greasycheeseman

sorry for taking your post in the wrong way jrat... i knew people were gonna say something about search when i decided to post this...

PhatManBUD

yanno, my friends FD has a problem with over heating, might be cause you dont have the plastic piece that goes under the engine bay towards the front that directs air flow i think, i dunno just a suggestion. i have an FD so this might be outta my knowledge, it would be cool if that was it tho. so let me know haha. good luck.

greasycheeseman

actually, i have all the plastic air direction stuff, and everything *looks* like it should work without any problems. but it starts to overheat... ugh... but im going to get the radiator serviced, and eventually buy a new one hopefully... but my fan also seems like it has a problem... has anyone used the fan with the clutch locked so it spins at the same rpm as the engine?? i thought about this, but i dont know if the fan could take it or not. suggestions?

Amur_

https://www.rx7club.com/forum/showth...threadid=29465

SureShot

I did that on my 87NA.
The old clutch was worn out & the new one was on backorder.
I ran a bolt right through it.
That cooled it right down, so I knew that was the problem.
Since the clutch was locked the fan drag was high enough to slip the belts at 5K.
I just kept the revs down until the new clutch came in.