a_sik_7

I have a 93 with a JDM motor with 11k and a single turbo T04. I am running into a problem with the car gettin really hot. Now i do have a Re Anemiya radiator and the cooling fans are now rigged to turn on with the ignition. I have have four place to monitor temp one the stock gauge no help second is the power FC although C is not too easy to read. Next an aftermarket gauge but tapped into the filler neck and next is a thermal gun. Now i had a compression check im good i also had a overnight coolant pressure check and im good there. Now the temps have gotten hot but i havent dumped the coolant. Next i have a high pressure bleeder valve tapped into the cooling hose that enters just right above the coolant temp sensor (this also illiminated an air pocket). So rather then cycling everthing i use a numatic siphon and suck the air out of the system hence no coolant light. I had an old thermostat and i replace it with a new factor mazda i had a feeling it wasnt opening since i was hot on the back side of the filler neck and the radiator was cool to the touch. Now i just done that today i started it up let it go to operating temp and i felt the coolant flow through the upper radiator at 180. SO that works, i drove around the block it seem to do good temps went up and down but when i pulled into the drive way it started shooting up now when i thermal gunned where the sensor was it was reading high, like inside the cab now i thermal sensored the filler neck reading about the same maybe a little less. Now i thermal sensor the radiator hose and its half the temp so i follow on through same thing radiator about 160. Any ideas? Im gonna remove the water pump in the morning and check the blades (since this was a jdm motor sitting for years) Now see its not leaking at the weap seal and it spins just fine the belt was on tight Im thinking it might be the impeller blades but then again i dont know. I have heard it might be coolant seals but i dont know how to determine this? I hear compression check thats done, i hear coolant pressure check thats done. I have also heard check for a sweet smell at start up which could be a sign there is one there but its faint. All my motors have been this way (long story at wits end and have dumped more money into the car then its worth) If someone could please help me with this issue it would be appreciated. I have owned my car since 98 and its been nothing but problems. Thanks if anyone who knows these third gens can help.

RX7Crazy_84

iTrader: (1)

um it sounds like heat soak to me, its normal if ur not moving at all your temps will climb slowly for sure but arent ur fans coming on at certain temps?

a_sik_7

Well this is the situation with the fans i had stock fans but switched to slimline to accomidate my front mount. I know now that i didnt need to do that for the greddy front mount. But i had them wired to work on the three speed system i just got this car out of the shop ive been overseas with the military so i just want it reliable. Well i first thought hey the fans arent pulling enough CFM to cook my massiive radiator so i wired them on all the time with the ignition until i find stock fans. But that wasnt my problem they are keeping that radiator cool i have a thermal gun im shooting it with and its keeping about 160-180 when all this is going on hence is the reason why i changed the thermostat this thermal gun is pretty accurate. Now i check my water pump ( with out removing it i will do that in the morning it spins fine and there is no sound of grinding but since its a old motor i figure there might be bad impeller or deposits on it, but wont know till tom. Can i ask whats heat soak? Im not familiar with that term? Thanks again for your response any ideas are helping

FD3S2005

iTrader: (11)

umm why not tell us the high temps its getting to? vented hood? i live in florida and max on my pfc says 97c on hot days which is 206F dont know why people get water temp gauges when they have a pfc

if 180f is what your saying is the hotest then thats ok....... Heat soaked is like all the heat is in the engine bay has no where to go and stays there, get a vented hood would be a good idea to help it out a lot and drop some temps. Correct me if im wrong anyone

a_sik_7

Sorry my bad well its hard to say really when i read off the thermal gun on the back side where the stock sensor is it reads about 235F but i dont know if this is accurate due to i have a single turbo with out a heat shield. Now on the power fc it read 119C on the stock gauge it gets to the top of the white. Now when i thermal gun the front of the filler neck where my gauge external gauge sensor is it reads 225-230F same as in the cab now here is the twist i follow my radiator hose and temp drops to 160 if not lower all the way to the radiator now that will range 160-180F. As far as the hood i have a Siebon reverse vented hood with a scoop.

vrmmmpshhh

powerfc and water temp gauges read warm up temps very different. when my powerfc hits 80c the greddy water temp guage wont get there till 10 or so minutes later.

what speed have you wired the fans to go in?

id wire the fans back to stock and grab a datalogit and change the speeds the fans kick in according to temperature.

a_sik_7

I have heard that but this is after the car has driven down the road. Today i replace out the thermostat since it seemed like the old one wasnt opening. I warmed the car up and monitored the temp via the thermal gun on the stock sensor and (this is gonna sounds stupid ) but my other hand on the upper radiator hose i had to determine if the new thermostat was working. Well when the thermal gun hit 179F (this took a few to get to) i could feel the warm coolant flowing through the hose. So i thought my problem was solved it held around 180 or lower i left it to see if it would go higher but it stayed the same. I drove it down the street it seemed fine went around a few streets seemed fine started heading back home then temps started to rise it got up to about 220 when i pulled in i let it sit for a sec it started going up so i turned it off and left the fans on to help cool. SO i stopped for the night the last thing to check on my system is the water pump i removed the belt checked for play and for grinding and there was none. In a way i hope the impeller blades are pitted ot have deposites or even the shaft slipping. But i dont know till the morning please if i have not explained something clearly let me know and ill try to rephrase again thanks guys for the help.

a_sik_7

I forgot to answer ur last question for right now since im on slimline singe speed fans i have them wired with the ignition on a seperate circuit with a inline fuse. Now this is temporary till i can find some stock fans to put back in to run the three speed set up. Now these fans are cooling the radiator the thermal gun is showing its about 160-180. This is why i thought it was the thermostat.

car hugger

iTrader: (1)

What's your coolant to water ratio? I was originally following the manuals suggestion of 35/65 based on where I live . I recently switched to 20/80 and my temps dropped about 5 degrees celsius on average with 90-95F ambient.

That unshielded turbo is going to generate alot of heat.

Heatsoak is caused by the lack of airflow and coolant circulating through the engine when the car is off, or standing still while running. The heat generated by the motor and that turbo has to go somewhere and it basically superheats the metal under the hood, this is why your air temp will rise while driving in stop and go traffic.

Another reason you could be seeing such high temps is if you have intakes drawing in the air from the engine bay. That front mount is also going to slow cooling down for the radiator.

All these things will lead to higher temps. A vented hood will help. Cold airbox will as well. Heat wrap your DP, get the turbo shielded. One more thing that truly surprised me is how turning the heater on in the car will help your temps drop about 5 degrees C or more while driving around.

a_sik_7

Coolant to water ratio is 50/50 pre mixed solution. Its harder to find diffrent ratios, sorry ive been overseas for like 4.5 years so everything in the states is new to me again. Now i have ordered a heat shield for the turbo im currently waiting for it. But i was thinking my sensor readings are off since that single turbo on the exhaust side is close to where the stock temp sensor is. To me when i read the temp with the thermal gun and its 230 on the side with the sensor then i shoot the housing and its about the same then i go over to the filler neck and its reading about 220 after i shoot the radiator hose and its like 160-175. It seems like heat is transfering to the radiator neck casuing my aftermarket gauge to read hot but i dunno what do you think? I figured that front mount would restric air but thats why i went with a greddy since i see alot of people running them no issues. I dont have room for an air box since i did the single conversion, Any one with a single have an idea? The down pipe is wrapped with thermal tec and im still waiting on the shield for the turbo itself its in the mail. I do have a vented hood the Seibon. I will try the heater to help out. Thanks again for your help

Eggie

I wouldn't put much trust in the infrared temp gun. And if my PFC showed 119C, I'd be VERY concerned. You should never have let it get that hot IMO.

Sounds like the liquid side works correctly. Time to think about airflow. Do the aftermarket fans move enough air? Are they both pulling air through the radiator? How straight are the rad's fins? Is the undertray installed?

FD3S2005

iTrader: (11)

could it maybe be a bad radiator or ducting to it? i remeber when my radiator just failed and my temps were ok at normal driving (on the highway at night only with cool temps) but if i went wot my stock gauge was rising almost to white so i ended up getting a fluidyne and it fixed my problem

pomanferrari

iTrader: (1)

Are you running an aftermarket AST? Some aftermarket AST do not have a restrictor orifice on the hose that goes into the bottom of the stock AST to the radiator so what happens is that all the water flows through the AST instead of the radiator.

Symptons will be a cool radiator but your AST is hot as **** and your engine is showing overheating.

car hugger

iTrader: (1)

Definitely lower your coolant to water ratio unless you frequently see sub freezing temps on a regular basis. Drain a gallon of coolant out and then just add a gallon of distilled water only. This will help.

Interesting info pomanferrari.

FD3S2005

iTrader: (11)

think some redline water wetter will help?

scotty305

iTrader: (2)

Where did you buy the thermostat from? If it's not an OEM thermostat, I'd replace it immediately. Also, be sure that the 'jiggle pin' is at the top of the thermostat. Personally, I drilled a few small holes in my thermostat, and I like how cool the car ruuns now.


I would also check to make absolutely sure there's no air in the system, and I'd also switch to a 70/30 water/antifreeze mix.


Also, check this thread out, just for kicks:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/big-fat-fd3s-cooling-thread-571088/


-s-

FD3S2005

iTrader: (11)

im just curious how much cooler does the car get with a drilled thermo? and does anyone have a pic to compaire to the stock one?

scotty305

iTrader: (2)

It's tough to say exactly how much cooler the car runs: on the highway I regularly see below 175F (because coolant is flowing through the radiator even when the thermostat is closed).

Here's a photo. Notice the jiggle pin is at the top of the thermostat, and most of the holes are the same size as the jiggle pin:



-s-

FD3S2005

iTrader: (11)

whell i still have the stock one, never has been changed does it have the jig pin? any write up how to remove and do this? i would only drill maybe 1 more hole not 4.. i just want a couple degrees cooler

a_sik_7

Thanks for the help and the info i am going to take a break for a few and go out for a few days i will respond to everyones comments when i get home on sunday. I will answer a few questions i know 119C is way to hot for this car thats why it is sitting. As far as the thermostat it is a factory mazda one. I am going to try to bleed the coolant system again it appears that the coolant is not flowing through the system. I thought i had it after i checked the water pump which was good i bleed the system on the radiator and on the engine side. I flushed the radiator so its still good it has less then 10k on it. It also has a bleeder valve on the radiator itself so i will attempt to bleed it again. At an idle i brought it up to operating temp and i could feel the coolant going through the system. When i drove it down the block it seemed to operate just fine and hold temp after about 10 minute the temp started to sky rocket 100C-119C which is way to hot on so i got it parked and check the temps they were high even with the thermal gun. Next i started to thermal gun the radiator hose and it was 170 then followed it up to the radiator it was 130F at the top then i followed the radiator to the end which was at 90F.So i am having a flow problem i think i need to bleed it more there might be another air pocket in the system not allowing the coolant to flow. But im gonna take a break like i said i will be back and will respond to everyones post. If i cant figure this out by next week im sure im gonna part it out and sell the car as a rolling chassis. SO if you all know anyone who is interested, i have had enough with this car and invested way too much i will post pics of the car on sunday or next week. Again to all who have posted Thank you. It is well appreciated i will be back on sunday and relpy to everyones post.
Thanks

FD3S2005

iTrader: (11)

kinda harsh, selling the car because you cant find an over heating problem yourself

hus

water pump

RX7Crazy_84

iTrader: (1)

umm geez bud is your airpump removed if so i would check the tension on the water pump it mite be slipping and if your air pump is removed what kind of kit do you have on their

scotty305

iTrader: (2)

Here are my suggestions, in order of most likely culprit to least likely:


1. If you're not using the OEM fans, I can almost guarantee that you're not pulling enough air through that radiator. Especially if you've got "slim" fans: aftermarket fans aren't usually well-ducted, so they'll pull air from around the radiator rather than through it.


2. As mentioned by others, if your accessory belt isn't making good contact with the water pump pulley, you won't see sufficient coolant flow and the motor will try to overheat. It's pretty likely that you've removed the air pump to convert to single turbo.


3. I'm not sure if using vacuum to "bleed air" from the system is a good idea. You can check this by running the car and letting it warm up, then cooling it down overnight and checking the coolant level in the morning. If the coolant level drops, there were air pockets in the system.

I recommend this tool, it has always worked for me.
Coolant Burping Tool/ Radiator Cap Funnel
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/radiator-cap-funnel-eliminate-air-bubbles-342309/



4. Switch to a 70/30 water/antifreeze mix ASAP. 50/50 just doesn't transfer as much heat.


5. How old are your pressure caps? New pressure caps are less than $20, which is a pretty cheap fix. They will ensure that you're not boiling coolant when the system gets warm.



6. If you've plugged or rerouted any of the coolant lines, you might want to put everything back to stock configuration and see if that helps. Do you still have the AST?


-s-

a_sik_7

Thanks again guys for the help. I am going to try a few of your suggestions this week. As far as my radiator goes its in excellent condition no bent fins and it flows just fine. Prior to removing the water pump i check the external for signs of failure like grinding and looking for shaft play which there were no signs i also checked the weap seal for signs of leaking and there were none. I did remove the waterpump incase there were deposits or pitting on the waterpump blades but everything checked good. So i reinstalled it back on and verified no leaks around the new gasket. I thought i had everything good i filled the coolant bleed out the radiator then bleed out the engine side and it appeared to be functioning fine and holding temp so i took it down the street and after about 10 minute it started to jump in temp. Now i agree with that i need to go back to the stock 3 speed fans, but i have been looking for replacements and been unsucessful. But i am almost forcertain that the fans are not the issue these fans are pullung through the radiator you can feel the air being pulled from the opposite side. Another reason why i dont believe these fans are causing my failure is that the temperature measurements at the inlet side of the radiator are about 130 at operating temp then at the other side of the radiator it drops to 80-90 degrees. So the functionality of the radiator is fine. I might have an airpocket in the system causing the flow to stop that is what it seems like to me. I will try the 70/30 coolant mix and even the holes in the thermostat that seems like two good areas to start i will also attempt to burp/ bleed the system as stated by that link so thanks for all that have posted good info and ideas.
Now to answer to the comment about selling the car because i cant find my cooling problem. Now i have owned this car since 98 i bought it with 44000 miles on it it currently has 72000 miles on the chassis and its been nothing but problems since day one. It had one good year and a half where it was reliable and ran like a champ but then due to having a not so reputable business build the motor that motor blew at 12000 miles and it was nothing special just a street ported motor. So between trying to get this car reliable to buying a used JDM motor with only 6000 miles on it (by the way never buy a used motor its better to do a full rebuild) So its been a frustrating mess now i bought this car when i had a well paying job and money to spend but i ended up leaving my job to finish my education and now i just cant afford to keep dumping money in a sinking ship i mean thats all it has been for me. Now someone else who has the money to spend can make this an awesome car it has rims full body kit and majority of everything has been replaced one way or another. But right now im to the point in my life where i am going to have to let this go. So yes i agree it is a harsh reality but when you have dumped alot of money into something there has to be a point and time to let go. And just abit of background on myself i am not a magazine mechanic i have owned my own shop building cars i actually built 14 cars (non rotary) in the SLC area now this was back in 98-00. I have had 11 cars all under 13 second 1/4 miles (by this 13 seconds was the slowest ive owned) I do it for the build and for myself but this car has just been a nightmare for me especially not having a background on rotaries that is why i am reaching out to other fellow RX7 owners for help. So for all who have posted i thank you again for the help i will continue to keep this update until i have solved this mess or decide to part ways. I have a feeling that the coolant seal have been everheated due to the high temps so the motor might be up for a rebuild one which will be my stopping point with the car. If this happens i will remove the single turbo, Trust Front mount, Trust elbow and BOV plus the Apexi Power FC and the AEM boost controller and sell the car as a rolling chassis with motor trans and ecu without turbos. So if this happens then i will keep people posted who might want a new Full tunned turbo system for there FD by new i mean all the items have less then 2 miles on them so ya thats brand new especially with no wear. Well im off for the night ill check back tom. Thanks to all who have posted again