SpeedracerRX7

Ok here is what happened. Friday night I was out cruising around for a couple of minutes I stopped to talk to my friends for a while. I sat in the car and let it idle for about 10 min before I turned it off. When I got out I noticed a puddle of of antifreeze under the right front headlight where the overflow is. Immediately I knew this was bad so I took it home and decided to work on it the following day.

I let it idle with the AC on so I could replicate the problem and sure enough the temp would rise slowly but surely and not stop and when the PFC read 103 Celcius the coolant would pee out of the car.

I started with the easy fix of a new radiator cap but it didn't seem to help, so I moved on to the next possible solution. I thought the thermostat went bad so I decided to replace it next. Never being fun I never-the-less got it finished. I took it out for a spin at night and everything seemed fine and it didn't go over 95 degrees Celcius.

Today(Sunday) I had to drive it from Delaware down to Charlotte, NC which was around 500 miles. About 120 miles or two hours into the trip the temp slowly walked from 95 up to 102 and I pulled over, shut it off, and opened the hood to let it cool down. I let it sit there until the PFC said 70 and so I took off again. 30 miles later it started running up again and when it reached 99 I cranked the heat all the way up and it helped regulate the temp down to about 96-97. The next problem was that I could only run less than 65mph or it would rise above 100 and I would have to stop to cool it off. Somehow I endured the rest of the ride with heat on high and only having to stop once more to cool off and once for gas and a short cooldown.

Being that I changed the thermostat and the cap what else could it be? I do have a Fluidince radiator and I have never had a problem before. The coolant also seems to be high enough. Nothing seems to be leaking and the coolant is free of oil or discoloration. No coolant in the exhaust and motor seems to run fine(3 months old and broken in). If you made it this far thanks and any input is appreciated.

djantlive

Is the water pump going bad by any chance? Also, could your fan relay be faulty? Did the fans come on when it's hot?

Alpine

does your coolant sit at top of the filler neck when cold?

SpeedracerRX7

Forgot to mention that the fans did come on when it got around 90 or so. The temp would go down to around 96 or so during the trip when I pulled over and let it idle for 3 or 4 min. Also while the heat heat was on and I slowed down in towns the temp went down but when I was up to speed(60mph or so) it was hard to keep it down. The coolant sits about 4 inches down in the filler neck but on the stick it seems ok. Is that good? Thanks again.

HYDOUKEN

iTrader: (1)

HI I have the exact same problems with my R1. Hey SpeedRacerRX7 have you figured out what the problem was? I also have replaced my radiator with a Koyo, replaced thermosat (180), mixture is straight water and water wetter (redline), both fans come on and working properly, replaced both AST and radiator caps.......what could be the problem? Also the onlyway I can get the car to cool down is to pull over and let it idle until the coolant temps come down. But as soon as I take off down the road.....in a matter of minutes I will start to over heat again.

hapa

If your loosing coolant, you need to do a pressure test and find out where your leak is. Now if your not losing coolant check your coolant system parts. Start with Thermostat, AST, Radiator, and caps. Then check to make sure your fans are working properly. Next make sure that the radiator is properly ducted to the front of the car. Make sure you don't have air spilling around the radiator. This makes a huge difference. If you still haven't found the problem, do you have a downpipe? How is your main cat.? Maybe you have a clogged cat or pre-cat. Report back with more information.

eric

HYDOUKEN

iTrader: (1)

Hey Eric I actually have a 3' stainless steel dp and mp with stock cat-back. I have replaced my radiator with a koyo, replaced my thermostat (180), replaced stock ast with Pettit AST (with new pressure cap). I still overheat when I am riding down the road, the only way I can get the car to cool down is to pull over and let the car idle....the temps will return back to normal. Please help!!! I am hating life without my FD.


Thanks for any info that could help

hapa

Hydouken, is your radiator sealed to the front of the car? I'd make sure that your not losing air around it. I've never heard of anyone with a good cooling system having so many problems. I assume you have a power FC and your using it for temperature measurements? If so, have you checked the voltage output of the tempurature sender, maybe your car isn't overheating, but your sensor could be bad. Also did you have these problems before you did all these cooling mods? List your buildup and the problems from the beginning. Also do you have an aftermarket temperature gauge?

eric

HYDOUKEN

iTrader: (1)

First off thanks for taking your time and reading this post. Well once summer started to come around my car started to overheat up to 104c. I would have to shut the car down, once the car cooled off I would continue driving down the road and it would overheat again. And yes I have PFC. So i thought it was maybe the catylitic converter (since the car would only cool down if I let it idle on the side of the road or let the car roll in neutral....engaging the air pump).So I purchased a new mp hoping to get rid of the heat. This did not fix the problem...cause I took it for a test drive the car started to overheat up t 97c. I shut her down once again. So now I am thinking its the radiator. I replace it with a Koyo. Same thing is still happening(overheating) but at a slower rate. Now I am thinking since the new radiator helped, but its not cooling the car fast enough....maybe it might be because the thermostat is not opening all the way. So I purchased a new thermostat (180). This once again seem to help the overall situation, but still overheats. So now I am thinking its the AST.....because everytime I shut the car down the overflow tank is spilling water out.....causing air bubbles in the system...thus causing it to overheat. So I purchase a new Pettit AST. Now the car is not spitting out water anymore.....so now I am able to purge the system properly...no more air bubbles. But yet the car still gets hotter than I would like .....crusin' down the highway it still reaches 97c. So this is what I have done so far to solve this weird cooling problem. How do I check the sensor to make sure its working properly.....doesnt the stock coolant guage use a different sensor than the one that the PFC uses?


Thanks again.

hapa

Ok, well at least we have a baseline for your cooling problems. Since we know that the Radiator and AST are ok, let's move onto other parts of the system. Have you ever had the coolant system pressure checked? I would do that first, just to make sure you don't have a coolant leak. Next, did you install the thermostat yourself? I'd check to make sure that the jiggle pin is at the top, so that it opens properly. So if your idle, and your fans are on your radiator (provided enough air) cools of the car correctly? So I assume if you leave the car idling it will show under 90degree temps right? Sounds like your radiator isn't getting enough air. You don't have a front mount intercooler by chance did you? The Power FC reads the engine temps off the sensor on the side of the motor, this is different than the stock temp. gauge. Check under the sensor check in the power fc menu and look at the voltage in of the h20 temp sensor. Then compare it to the shop manual and let me know what you find.

eric

HYDOUKEN

iTrader: (1)

No I haven't had the system pressure tested. And yes I installed the thermostat myself (stant thermostat doesn't have jiggle pin).And yes when the car is idling and the fans are turned on the car cools itself off. Yes the engine temps will stay below 91c if car is idling with fans on. I still have the stock intercooler and the only thing in front of the radiator is the a/c condenser. Remmber that all this hapened when the car was bone stock....andstill happens exactly the same after upgrading the cooling system....just at a slower rate.

hapa

Well, I would change the thermostat to an OEM Mazda one. They only cost $12. Your belts aren't slipping right? I'd make sure your getting proper tension on your waterpump, maybe it's not turning fast enough. Do these and the pressure test and see what happens. Also double check your water temp sensor voltage, you never know, it's worth a shot. When you put on the midpipe, did you remove your airpump? If so did you also add pulleys to change the alternator/waterpump/airpump belt? Does your car have any problems starting (cold or hot)? Has the waterpump ever been changed? When you changed to the Stant thermostat was the old one a Stant as well? Or Mazda?

eric

Tom93R1

iTrader: (2)

What are the syptoms of a failing water pump? Is it possible for one to fail in any other way than leaking water around the pulley shaft? These guys both seem to be having the same problem I have. I just put in a Koyo, new upper and lower hoses, and replaced my thermostat with the Stant part. I run about 20% antifreeze/coolant, 80% water with a bottle of water wetter.
When I drive home from work in the heat of the day I watch the temp climb fairly rapidly to 87-88, then it goes about 1 degree per minute if I have the A/C on and fan speed 2. I usually let it get to about 103 then turn the heat to full blast, the temp drops 1-2 degrees a minute and I fire up the A/C again for another couple minutes before I get home. Then when it starts to cool off the overflow overflows, peeing on the ground. Next time I go out to the car the coolant level is about 4" below the filler neck. The only water that leaves the system is through the overflow, no white smoke or smell from the exhaust.

This weekend I am probably going to switch back to a Mazda thermostat. Who can do pressure checks on a cooling system, places like Midas? How long will that take to do?

haha, maybe you can buy an overdrive pulley for the water pump

HYDOUKEN

iTrader: (1)

What is the difference between the two thermostats......stant is a very good brand when it comes to cooling system counter parts. I am not sure if the belts are slipping or not (they are sqeaking). I went outside and tried to turn the water pump pulley......and I can turn it by hand if I put enough pressure on it with my hands (this is still with the belt on.....is this supose to happen)? Do you know what the proper voltage is supose to be? And how do I read the voltage...while the car is running or not? And when I installed the midpipe I did not remove the air pump...but plan on it with a full pulley kit that will replace the altenator, power steering,water pump, and eliminate the smog pmp. And no I don't have a problem starting in cold or hot weather. Just recently I have had general starting problems....but that is due to the low charge on the battery (yes I know I will replace it as soon as I figure out this coolin problem). And no I have never changed the water pump before and the thermostat that I removed was a mazda OEM I think....it had a black rubber gasket on the inner part of the thermostat...it was beginning to deteriorate and was probably getting into the cooling system. the stant one is clean and looks to be of high quality.


Thanks again for helping me diagnose my problems

hapa

Hydouken,

I just think the Mazda part is a better piece to use. I have no idea about the stant thermostat, but the Mazda has a jiggle pin on the top. I would always use the OEM thermostat. But I don't think thats your problem. I think all three of you are having pressure problems. I would first have my cooling system pressure tested. Also have you changed your radiator/ast caps? I would buy new OEM ones and install those. It really sounds like both of your cooling systems are working, but you have pressure problems. This is causing the temperature spikes, and the loss of coolant when the motor heatsoaks. Changing the caps and thermostats to OEM are an inexpensive proposition, so try those first, then pressure test. If your still having problems post back and we'll see what we can do. Tom a failing water pump shows itself by making a slight noise, and with mine water started to leak around the gasket. I would make sure your belts are tight enough NOT to slip, but not too tight. It's kinda confusing, but you have to get it just right, don't overtighten it, it will kill your waterpump.

eric

HYDOUKEN

iTrader: (1)

.So should I be able to turn my water pump by hand even with the belt still on? Cause when the car is running it turns the water pump...and when the car revs up it seems to be spinning at the same speed, from what I can tell. But when the car is off I am able to turn the pulley by hand if I put some pressure behind it. IS this normal? Yes I have replaced the whole AST with a Pettit unit which came with a new cap also. But I still have the stock filler cap on the car. So I guess the next step is to pressure test the system ,huh?

artowar2

If you have traced the source of the leak to the overflow bottle, and the stick on the overflow bottle reads normal-to-higher than it should, and you are consistently low on coolant at the filler neck, then I suggest checking:

1. the AST cap, to verify that it still opens to suck back coolant from the fill-bottle, and

2. the hoses that run between the AST and the fill-bottle.

If either 1 or 2 fails, then coolant can be pushed out of the AST to the overflow bottle when hot (as it should), but can't be drawn back from the overflow bottle to the AST when cold. Thus, coolant keeps filling the bottle until it overflows, and the motor is constantly low on coolant.

Both the AST cap and the hoses to the overflow bottle are known to go bad. Obviously the cap is easy to replace, and the hoses are as easy to replace as they are to check properly. The tricky thing about the hoses is that they can fail with a pinhole leak that is hard to find. Just buy a few feet of same size hose and replace. They get plugged up with that coolant-crud anyway.

Of course, it's possible that you've lost a coolant seal on the motor, but you don't seem to have the other typical symptoms of that problem...

HYDOUKEN

iTrader: (1)

This morning I went to top off the coolant (like i always do, since I can't figure out what te heck is wrong with the system always having to be topped off) through the filler neck. At the same time I popped the red tab on the pettit AST cap (which lets off pressure and air so that you can purge the system). Anyways I started to pour water in the filler neck with the red tab popped up and then I noticed that the water I was pouring into the filler neck was coming out of the overflow tank. So obviously the AST was full and pushing the water out to the overflow. Remember that the car is completely cold. So does this mean the reason why my coolant is always in the middle of the filler neck and never topped off is because the coolant i not being pulled back in? I am pretty sure that the AST is good since I have only had it on the car fo a coupl of days......and ever since I have installed the new AST the car doesn't make the boiling sound anymore once it cuts off. But I guess it sill isn't pulling water in? Can I replace the line that goes from the AST to the overflow with a silicon vaccum line? I know it can take some heat since i used the same hoses that sit right on top of the motor ( rats nest)

lane_change

iTrader: (20)

Well here comes number 4. I have just replaced my Blitz SMIC with a Blitz FMIC and I also replaced my radiator with a Fluidyne. I had just started it up after a 6 long sit and it ran fine for a while. I have the PFC as well and my reading jumped from 31'C to 114'C in about 2 minutes when I wasn't looking. I turned the car off and could hear boiling coming from the AST and the Radiator cap but no leaking. I checked my radiator and it was cold. So I assumed it was the thermostat and I replaced it with a Stant from the local parts store and the problem was fixed for about 1 minute.
At idle it was 92'C but as soon as I went down the road it climbed up to 106'C and I shut it down and let it cool down some and took it back to my shop. Once there I began to look for any pausable causes because it ran fine before I ever changed all this. I noticed that the line from the AST to the overflow tank was unknowingly zip tied around something causing a kink in the line. So I undid the tie and filled the coolant up some more with water and now it seems to be running fine.
Averaging between 86'C and 90'C driving around and it rises a bit at idle maybe 91'C or so but not bad. I am praying that nothing happened to my motor when it hit 114'C. Hopeflly it is all over and everything is back to normal. Is there anyway to check for water seal failure due to overheating?
Thanks, Scott

HYDOUKEN

iTrader: (1)

WOW I can't tell you how much you have helped me HAPA. Sorry for not responding for awhile but I was having problems hot starting....fixed now. But now everytime I go to fill the car up with water it is only about 1 inch from the top of edge So I guess after installing all the new parts it just took a coupe of days to work the air out. I think now that I look back on everything the main causes of the overheating was because of the thermostat (being old and didn't open 100% properly),bad pressure seal on the AST cap......and hoses not connect properly (to prevent any tiny air leaks ) going to the overflow bottle. like said these were the main problems with my car overheating...now that I look back on everything. But the Koyo radiator did help alot
Once again thankyou HAPA for all your help!!!!!!!!

artowar2

One shortcut to burping the air out of your cooling system is to disconnect the coolant hose at the back of the throttle body. Put some rags under there while you fill the system and squeeze the hoses. Just remember to put it back on before starting the car.

jspecracer7

I recently started to have cooling problems, but because of this thread...I'm fixed!

I give it a up!

Carlo

I am also getting cooling problems now with my RX7, and I cannot work out where the problem lies. My filler cap needed replacing a couple of months ago, which I replaced, and now when the car is running everything seems fine, the temperature guage never goes above half way on the guage, but when I park the car, I see a puddle of coolant appear by the front wheel axle, and when I look at the coolant the filler neck is full but the coolant in the overflow bottle has gone down from the Full mark to the low mark, I think I am losing about 1/4 litre of collant a day after driving 100 miles. I am topping it up daily and always lose approx. the same amount of coolant, When I stop the car and turn the engine off the fan automatically cuts out as well, is this normal? have I got pressure problems, sticky thermostat??anybody had this before? got any ideas??

Tom93R1

iTrader: (2)

I figured out that if my car is over about 98C When I shut it down the overflow will overflow, leaving a puddle and somehow causing air to get in the cooling system. Monday I pulled out my week-old Stant thermostat and dropped in the Mazda one. Since then my car hasn't seen over 97C, after which it quickly dropped back to 92-93. This is driving in temps over 110F! Cooling problems resolved for me

Crash

A week after I had my RX I would get a low coolant buzzer chack eveythin fluid would be fine mostof the time bleeed the air two days later low coolant buzzer again anti freezer over flowing from resivior on pass side well i change the water pump with the whole front waterhouseing that the peice withe all the metal water neckseverything really pita but after that no buzzs no high temps ran greeat