ok my car has has overheating problems for quite some time. i thought it was a result of the belly pan that i forgot to reattach (when i put it back on it helped but not much). i still get some pretty bad overheats where i need to pull over to the side of the road for it to cool down. i have verified that the fans are working (but i can only assume that they are turning on at the proper times)... i dont usually overheat w/ the AC on which forces the fans to go on high... so maybe they are not getting the proper signal (im assuming there is a temp sensor...maybe it is bad?). everything else seems in order. i have a new thermostat, but i wanted to ask before i tear the car apart once again if there are any other likely culprits. after a few hard pulls the coolant buzzer usually come on telling me i have low coolant, and the temp gauge starts moving (i just have the stock one right now). then after a few seconds the needle just drops, and the coolant buzzer goes back off and all is well. other times the temp gauge will keep rising, the coolant buzzer will go off and the car will overheat (at which point i get stuck on the side of the highway). when i open the hood everything is overboiling, the caps are whistling trying to vent pressure, and coolant is pouring out from under the car. ive checked everything and cant find any problems so far.

as of now the entire cooling system is stock... i have an extra KOYO rad. in the garage (it is for another FD im working on ) but i may throw it in this car if i cant get this overheating under control. any help diagnosing my overheating woes would be much appreciated. thanks.

 

any one have some wisdom they'd like to share?

 

what kind of cooling do you have on your fd....stock rad and intercooler, what about oil cooling??

 

Rotormotor,

I remember your old thread...but not the specifics...what kind of thermostat did you replace it with? OEM or an aftermarket one?

 

is it possible you have an airlock in your system somewheres??

 

7racer: i didnt replace the thermostat yet (i have a new OEM one that will be going in tomorow) but i have this sneaking suspicion that the t-stat is not the problem.

obvious: airlock?? please explain, im not familiar with that

 

Replace the t-stat! My t-stat went out on me last summer and resulted in almost overheating on the highway.

It's a little curious that you would suffer from overheating over the course of a few months and never replace the t-stat. Any particular reasons why you don't think it's the t-stat?

 

Rotormotor!

replace that thermostat!!!!

Do you know what kind was is in it currently? I would think a failed thermostat would be the most likely culprit??

Anyways, I want your car to run right so you can give me some feed back on that knightsport high-flow cat!!!! BTW, jt-imports has a similar cat but without an airpump pipe. He stated that the cat passes emmisions like the stock cat....so now the question is really about flow!

 

Are you overheating with the 20B or the 13B FD?

 

because the problem comes and goes... id think that either it overheats all the time or not with a problematic t-stat. i bought a new one just incase, but i just think its something more complicated than a broken t-stat from the symptoms.

some more clues for the day: -> i was moving the car to my new house and had to drive it on the highway today. all was well untill i hit a section of the highway where it gets a little twisty and hilly. i saw the temp rise a few times and then as im about to pull over the needle shoots down to the normal range. then it happend liike that a fe more times untill the coolant buzzer went off and then it started rising and would not drop back down. i pulled over, popped the hood, and (as a result of frustration with the car) decided to just pull the rad. cap off. that was fun with hot steam spraying everywhere.. i had some water in the car to replace it with. when i looked down at the rad. cap kneck i noticed something very interesting/disturbing. there were a few chunks of some sort of grey rubbery selant in the water that was sprayed out. i have a feeling i know what it is (and im now woried about my coolant seals)... but im not 100% sure what it was so i thought id ask. ill post a picture of this stuff tomorow... its grey, rubbery, and flexable. what is it?

so i get the car home and tear everything apart tonight to get to the radiator, t-stat, and a fe other things im fixing. i noticed something bad on the fan assembaly as well. there was a wire (teh yellow one on the drivers side fan ) that looked like the insulaion was worn down and the wire was grounding to the metal fan motor behind it. il also post pics of this tomorow. hope these clues may be of some help

 

ask for feedback and you shall receve ! while im in here replacing the t-stat and rad. im also pulling my turbos to port the wastegate for the KS cat (just incase hehe)

 

13b... the 20b car is still being prepped and im still waiting on the subframe sadly... soon, soon (i hope)

 

id change out the radiator when you rip everything apart too, could be clogged. what color is your ast? if its not black i would take that off too.

 

haha ok its the t-stat! i pulled it and checked it againsed the new one and the old one opens at a higher temp and only 1/3 of the way. rynberg wins!

so now since the radiator is out ill put the koyo in. im still wondering what these rubber chunks were. ill post a picture. i also pulled my turbos and noticed a good amount of white residue on them... i wonder if im leaking coolant into the engine. i dont have any white smoke or any bubbles in the filler kneck so im not sure what hte deal is.

also, since i have a thead going ill have to solicit your advice for what to do with my turbos. i have a spare set which is not as cracked so ill be replacing the exhaust housing for the secondary turbo, as well as porting the wastegate. i used to have problems blowing smoke at high RPM's so i was thinking the secondary was bad. is there any definitive way to test the turbos besides just running them? (the problems i was having were sporatic).

basically my options for the turbos are A) do nothing and just port the wastegate seeing as the motor has 84K miles on it and will probably blow soon, killing my turbos possibly B) try to determine which of the 4 rotating assembalies are in the best shape and use the 2 best in my twins C) just get a rebuild kit and rebuild each one (and hope my motor doesnt die and kill my rebuilt set) D) maybe there is an option that i havent thought of yet, in which case you should inform me of it (PS i dont want a single)

thanks for the helping me get this poor car running!!!!! -heath (ill post pics of a few things that i think warrant concern)

 

Hey I thought I made the suggestion about the t-stat!!!

jp


glad you found the problem!!!

 

The easiest and cheapest thing to replace and the also the first thing you should check if you engine is overheating!

 

sorry 7, you did. hats off to you as well . hopefully that is the extent of the problem... but im still thinking about doing the miata thermoswitch as extra insurance on top of the koyo.

 

any comments on my turbo predicament?

 

ok here are a few pictures... here is one of the rubbery greyish silver chunks that came out when i pulled my radiator cap off. can anyone identify what this may be? looks like some sort of sealant to me


here is a picture of the white buildup in the turbos... could this be due to coolant getting into the combustion chamber?



old turbo cracks



is there any way for me to test if a turbo is bad outside the car? should i just rebuild them or guess which ones are good and mix and match between the 2 sets?