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I've been doing research and I haven't found anything solutions that would work. it was about 91F in Florida yesterday and my FC Turbo was getting pretty hot on the freeway, not overheating, but it was getting there (100c, maybe more), it certainly would have if I went any speed over 80mph.
I have my plastic under tray, I have a Koyorad aluminum racing radiator that I've been using for a year now so its not old. I also don't have a blown coolant seal. Im running 1/3rd antifreeze to 2/3rd distilled water and ive replaced I don't know how many times because of a leak near the turbo which I fixed a few months ago so the coolant is in tip top shape. Im also using 2 v-belts to run my alternator/water pump so it doesn't skip like it used to because I don't have the air pump anymore
my clutch fan is fine and I think the car is getting proper air flow through the radiator or Im pretty sure it would be getting hot all the time
my car has a weird problem of taking forever to warm up when its just idling in my garage, but if you put it on the freeway or any speed above 60 mph and it gets hot really quick.
I'm fairly certain I've bled the system properly, but there was one time where I was heading home with a buddy and i popped the hood when I got home and noticed all my coolant in the overflow was gone (that did not happen yesterday though, coolant level stayed the same).
im fairly certain my thermostat is sticking but I'd like a second opinion so I can cover my basis
Do you still have the fender liners? Is the back of the car lowered? Both of these will greatly affect airflow through the radiator.
Replace the coolant too, you have the ratios reversed. You can get a much higher boiling point with a coolant-rich mixture. Sure, technically a water-rich mixture transfers heat better, but this does not help when the coolant is boiling at the spark plugs because the boiling point is too low.
Do you still have the fender liners? Is the back of the car lowered? Both of these will greatly affect airflow through the radiator.
Replace the coolant too, you have the ratios reversed. You can get a much higher boiling point with a coolant-rich mixture. Sure, technically a water-rich mixture transfers heat better, but this does not help when the coolant is boiling at the spark plugs because the boiling point is too low.
so 2/3rd antifreeze? I guess I could give that a go but id like a second opinion before I go do that just for piece of mind.
I'm not saying that is your problem. In fact, I don't think it's even related to your problem, you probably do have a seized thermostat. But it IS something to address while you're in there.
It's a different chassis, but I've noticed a 20 degree coolant temperature change with a 1/2" front ride height change on a certain hill I drive on. So airflow through the radiator IS important, anything that allows air to go under the radiator, or prevents it from escaping the engine bay, or allows to to get recycled through the wheelwell, is bad.
I'm not saying that is your problem. In fact, I don't think it's even related to your problem, you probably do have a seized thermostat. But it IS something to address while you're in there.
It's a different chassis, but I've noticed a 20 degree coolant temperature change with a 1/2" front ride height change on a certain hill I drive on. So airflow through the radiator IS important, anything that allows air to go under the radiator, or prevents it from escaping the engine bay, or allows to to get recycled through the wheelwell, is bad.
My car is lowered about an inch but no more, any more and my pre-silencer would be scraping over speed bumps. I believe the front is ever so slightly lower than the back, but if it is its only by a miniscule amount. the only thing I could add to improve air flow is that foam thing under the old radiator that makes a seal against the plastic undertray.
I'm not saying that is your problem. In fact, I don't think it's even related to your problem, you probably do have a seized thermostat. But it IS something to address while you're in there.
It's a different chassis, but I've noticed a 20 degree coolant temperature change with a 1/2" front ride height change on a certain hill I drive on. So airflow through the radiator IS important, anything that allows air to go under the radiator, or prevents it from escaping the engine bay, or allows to to get recycled through the wheelwell, is bad.
ok, not sure why my previous post decided to take so long to show itself... guess I have 2 reply's now......
so It got to 100C and stayed there? or kept rising? 100C isn't that high.
im using the stock gauge and it went above half, which as far as Aaron said in a post a while ago is already pretty hot. My microteach says slightly above half way is about 100c, so Id say 102 max but no more than that because I was limiting my speed. HOWEVER, any significant increase in throttle or speed and the temps would spike immediately, (like +2C instantly when adding about half a cm of throttle input) but again, it wouldn't go to H. It probably would have If i drove normally.
+1 on the coolant mix comment, go with either 50/50 or a 60/40 antifreeze/distilled water mix.
A bad thermostat is a good guess here, given the symptoms you have. Is it an aftermarket T-stat (Stant, etc.)? If it is, chuck it, those are crap and get the Mazda OEM part - never had good luck with ANY aftermarket T-stats on a rotary. Also, when installing it, pay attention to the FSM instructions & diagram that shows you how to align the T-stat's "jiggle pin" with the housing.
Another thing to check is your pressure cap - if it's not holding pressure, the car will boil over pretty quickly especially at highway speeds. If you can't test it, just replace it with the OEM Mazda part.
+1 on the coolant mix comment, go with either 50/50 or a 60/40 antifreeze/distilled water mix.
A bad thermostat is a good guess here, given the symptoms you have. Is it an aftermarket T-stat (Stant, etc.)? If it is, chuck it, those are crap and get the Mazda OEM part - never had good luck with ANY aftermarket T-stats on a rotary. Also, when installing it, pay attention to the FSM instructions & diagram that shows you how to align the T-stat's "jiggle pin" with the housing.
Another thing to check is your pressure cap - if it's not holding pressure, the car will boil over pretty quickly especially at highway speeds. If you can't test it, just replace it with the OEM Mazda part.
never had a problem with boiling over, just a problem with all the coolant in the overflow disappearing. also just to go over, what is the proper way to flush the system, just so I know I'm doing it right. right now I have a mishimoto thermostat to put in, its not like i can return it, ive had it for a while, ill see how well it holds up. and Ill add some non diluted antifreeze to the stuff Ill take out of the system to make it to spec (ive replaced the coolant i cant even count how many times recently, so the coolant in it should be good)
While its unlikely, id be curious to know what the oil temperature is on your engine. The oil is a percentage of the total cooling capacity of the engine, and if its running to hot coolant temperatures will follow. Even N/A when drifting after getting the oil temps over 220F the coolant temp starts to follow(as the oil temps rise). Usually the cooling systems on these cars seems to be mostly reliable, but i have run into thermostats in the oil cooler that were stuck(in my vert it was stuck open), but a stuck closed(cooler bypass) condition is just as possible and could bring water temps up.
While its unlikely, id be curious to know what the oil temperature is on your engine. The oil is a percentage of the total cooling capacity of the engine, and if its running to hot coolant temperatures will follow. Even N/A when drifting after getting the oil temps over 220F the coolant temp starts to follow(as the oil temps rise). Usually the cooling systems on these cars seems to be mostly reliable, but i have run into thermostats in the oil cooler that were stuck(in my vert it was stuck open), but a stuck closed(cooler bypass) condition is just as possible and could bring water temps up.
reviving an old thread of mine. just removed the thermostat housing to replace it. turns out this motor never had a thermostat to begin with -_- (I bought this motor to swap in my car, the only thing I checked was compression), which explains my issue with the car taking forever to warm up, but now im back to square 1 about why its getting hot on the freeway......
reviving an old thread of mine. just removed the thermostat housing to replace it. turns out this motor never had a thermostat to begin with -_- (I bought this motor to swap in my car, the only thing I checked was compression), which explains my issue with the car taking forever to warm up, but now im back to square 1 about why its getting hot on the freeway......
So it's still overheating with a new t-stat installed? You said the radiator is a Koyo that is about a year old, and since it sounds like coolant has been changed/maintained, I doubt it's a clogged radiator. But a clogged up heater core is still a possibility, and a radiator cap that isn't holding its rated pressure is another possibility. The pressure cap can be tested with a coolant system pressure test kit that you can borrow/rent from you local auto parts guy. For the heater core, you can test that out by temporarily bypassing the core. Connect the two hoses going into the core together with a splice pipe instead, go for a drive and see if it starts to overheat again.
Trying to understand how a clogged heater core can cause overheating issues. Wouldnt bypassing the heater core have the same affect as a clogged heater core?
Trying to understand how a clogged heater core can cause overheating issues. Wouldnt bypassing the heater core have the same affect as a clogged heater core?
Simple explanation - Any clog or significant restriction in the system would reduce the flow of coolant throughout the system, so coolant is no longer getting to the hot parts it needs to cool at the flow rates the engine's designer intended. Result is overheating under load.
No, bypassing the heater core simply removes that potential clog/restriction from the system for testing purposes. So instead of flowing thru the core, your coolant flows thru a splice (i.e., connect the two heater hoses at the firewall together).
Coolant would just bypass it as if you had the port on the side of the block capped off as well as the nipple at the lower coolant hose. The system doesnt rely on coolant flowing through the heater core, and a partially or completely clogged heater core shouldnt cause any restrictions.
The heater core hoses Ts into the coolant system, just as turbo oil feed line Ts into the block for oil.
Last edited by FührerTüner; Apr 13, 2021 at 09:33 AM.
reviving an old thread of mine. just removed the thermostat housing to replace it. turns out this motor never had a thermostat to begin with -_- (I bought this motor to swap in my car, the only thing I checked was compression), which explains my issue with the car taking forever to warm up, but now im back to square 1 about why its getting hot on the freeway......
Did installing a thermostat solve the problem? Having a missing thermostat would cause the exact issues you describe: taking forever to warm up and overheating under load.
Thermostats essentially work as a variable valve. Under cold start conditions it bypasses coolant around the radiator, simply recirculating coolant through the engine; this allows the engine to warm up faster. Under heavy load it shuts off this bypass, running all the coolant through the radiator to offer maximum cooling. Under light load cruising it will open a variable amount, running some coolant through the radiator and bypassing some back into the engine; this varies the amount of cooling to keep the engine at the desired temperature.
Without a thermostat it will always allow some coolant through the radiator (causing the long warmup period) and bypass some coolant around the radiator (causing overheating under load). The amount that goes through each path will depend on the restriction (backpressure) each path offers; I'm guessing the radiator offers more restriction than the bypass, so most of the coolant is probably going through the bypass and not being cooled.
Did installing a thermostat solve the problem? Having a missing thermostat would cause the exact issues you describe: taking forever to warm up and overheating under load.
Thermostats essentially work as a variable valve. Under cold start conditions it bypasses coolant around the radiator, simply recirculating coolant through the engine; this allows the engine to warm up faster. Under heavy load it shuts off this bypass, running all the coolant through the radiator to offer maximum cooling. Under light load cruising it will open a variable amount, running some coolant through the radiator and bypassing some back into the engine; this varies the amount of cooling to keep the engine at the desired temperature.
Without a thermostat it will always allow some coolant through the radiator (causing the long warmup period) and bypass some coolant around the radiator (causing overheating under load). The amount that goes through each path will depend on the restriction (backpressure) each path offers; I'm guessing the radiator offers more restriction than the bypass, so most of the coolant is probably going through the bypass and not being cooled.
yes it did, my temps are at least 8-10c cooler than it used to be on the freeway, most of the time if falls comfortably around 86-87c if I'm not hauling ***, though now I have another issue, that being the small amount of coolant slowly leaving my coolant overflow after every commute with zero indications of an external leak. Im gonna test for traces of oil in the coolant to see if I have a bad coolant seal, but I don't believe I do since I have zero symptoms. I checked the thermostat housing and it isn't leaking from there either, and i only removed that and the hose to swap the thermostat so I didn't mess with anything else.
Ive looked up how you do the burp procedure, but I don't quite get it. I did warm up the car, put heat on max and squeezed the lines till no more bubbles came up, so not sure if I just need to drive it and the rest of the air pockets will flow out into the reservoir on their own, though I have a feeling that's not the case. regardless ill keep it topped up with coolant to make sure air doesn't get back into the system.
So it's still overheating with a new t-stat installed? You said the radiator is a Koyo that is about a year old, and since it sounds like coolant has been changed/maintained, I doubt it's a clogged radiator. But a clogged up heater core is still a possibility, and a radiator cap that isn't holding its rated pressure is another possibility. The pressure cap can be tested with a coolant system pressure test kit that you can borrow/rent from you local auto parts guy. For the heater core, you can test that out by temporarily bypassing the core. Connect the two hoses going into the core together with a splice pipe instead, go for a drive and see if it starts to overheat again.
t-stat fixed the issue, though if you look at my post before this one, its out with one problem and in with another -_-
