K20Z3 head coolant temp sensor

[sleepy ep3]

Does anyone know if this is interchangeable with ours? I have the Z3 head, and it says the car is running hot, although in Kpro that doesnt seem to be the case, plus the hoses don't feel really hot. I'm wondering if I need to swap back to the A3 coolant temp sensor. Only happens when I'm on the HWY, not just cruising around. Thoughts? (block guard is installed, koyo rad, mugen thermostat)

[monjarassi]

Does anyone know if this is interchangeable with ours? I have the Z3 head, and it says the car is running hot, although in Kpro that doesnt seem to be the case, plus the hoses don't feel really hot. I'm wondering if I need to swap back to the A3 coolant temp sensor. Only happens when I'm on the HWY, not just cruising around. Thoughts? (block guard is installed, koyo rad, mugen thermostat)

im having the same issue bro, i get stupid reading at hwy speeds in the daytime but at night no issue, its as if the thermostat is locking up.. im getting the mishimoto one and see what happens. The other day on the hwy kpro registered 220 and the dam needle never moved to the h position..

[USAF EP3]

Our car's cluster has 3 postions:

Cold (bottom), Warm (just below middle position), and NEW ENGINE (H)

That sucks to hear about the temp reading issue you guys are running into. I'll do some part research.

[sleepy ep3]

I'm glad we have members like you usaf ep3. Im sorry to hear you are having the same issue Monjarassi. It seems like you said, that the thermostat is not opening. Once we get this figured out, it should be a sticky, so that other members don't have the same issue. Are you on the z3 head as well monj?

Just cruising around it doesn't do it, and on the highway it does. You would think; logically:
On the highway there is more air moving across the radiator, and the water pump is spinning faster, therefore it would run cooler that just puttering about. But it is also staying at a consistently higher rpm, for longer, so it somewhat makes sense?
I can't imagine it being the thermostat, as it's a Mugen, and brand new. The radiator is new, new coolant, no air trapped as far as I can tell, and I believe I hooked up all the hoses correctly. The Intercooler is big, but even if it blocked the radiator completely, it would still get some airflow. I'm wondering if the block guard is impeding flow, but is shouldn't as it still has holes in it.

IDK, I hope it's the sensor. After $1k for that damn clutch, I'm tired of paying for shit, I just want to drive.

*edit I looked up the part numbers, and they are both the same.

[USAF EP3]

I'm glad we have members like you usaf ep3. Im sorry to hear you are having the same issue Monjarassi. It seems like you said, that the thermostat is not opening. Once we get this figured out, it should be a sticky, so that other members don't have the same issue. Are you on the z3 head as well monj?

Just cruising around it doesn't do it, and on the highway it does. You would think; logically:
On the highway there is more air moving across the radiator, and the water pump is spinning faster, therefore it would run cooler that just puttering about. But it is also staying at a consistently higher rpm, for longer, so it somewhat makes sense?
I can't imagine it being the thermostat, as it's a Mugen, and brand new. The radiator is new, new coolant, no air trapped as far as I can tell, and I believe I hooked up all the hoses correctly. The Intercooler is big, but even if it blocked the radiator completely, it would still get some airflow. I'm wondering if the block guard is impeding flow, but is shouldn't as it still has holes in it.

IDK, I hope it's the sensor. After $1k for that damn clutch, I'm tired of paying for shit, I just want to drive.

No problem, I do what I can to :ephatch:

Something hit me as I was about to go part researching, I had this problem with my RX-7, I know it's a long shot but before you two start throwing money at something try this simple procedure first just to have peace of mind. I know both of you have built setups so this will apply.

The RX-7 would run normal city driving and below 50 MPH, but once cruising at highway speeds my temps would go up to 200*F (on a rotary you don't want it that high if you're not boosting). It had me puzzled because I thought my coolant seals were gone but I wasn't burning coolant.

Long story short, it ended up being a leaky hose that cracked at the clamp. When the engine had load on it, it caused the water pump to pump at a higher PSI (highway speeds + wind drag = more load than normal city). Go to your local parts store and rent/buy a coolant system pressure tester to make sure you dont have any leaks. Make sure to get the import radiator cap adapter for it too.

If this doesn't work, make sure you guys filled the coolant correctly in accordance with the factory service manual. Try these things before you gotta go tearing off the intake manifold and replacing thermostats and what not.

Now I'm gonna go compare temperature sensor part #'s.

EDIT:

Oh forgot to mention,

The reading K-pro gets (ECT*) is from the bottom of the radiator once the coolant has passed through it and ready to go back into the engine.

I have an aftermarket water temp sensor installed where the AAV used to be (directly above the exit coolant port) and it tells me the temp of the coolant coming right out of the engine so it's much more accurate than what the sensor at the bottom is doing. This way I can catch overheating way before the radiator overheats itself trying to cool off the engine.

So from what you guys are telling me, if your Kpro said 220*F, then your engine must have been around 230-245 range and that my good friends is no bueno. When my autometer reads 218~ my kpro reads 206 (when fan kicks on).

[02_epdriver]

Sleepy I believe he is running a full k24a1 long block if im not mistaken

[sleepy ep3]

sleepy i believe he is running a full k24a1 long block if im not mistaken

k24z1/k20z3

[monjarassi]

I'm glad we have members like you usaf ep3. Im sorry to hear you are having the same issue Monjarassi. It seems like you said, that the thermostat is not opening. Once we get this figured out, it should be a sticky, so that other members don't have the same issue. Are you on the z3 head as well monj?

Just cruising around it doesn't do it, and on the highway it does. You would think; logically:
On the highway there is more air moving across the radiator, and the water pump is spinning faster, therefore it would run cooler that just puttering about. But it is also staying at a consistently higher rpm, for longer, so it somewhat makes sense?
I can't imagine it being the thermostat, as it's a Mugen, and brand new. The radiator is new, new coolant, no air trapped as far as I can tell, and I believe I hooked up all the hoses correctly. The Intercooler is big, but even if it blocked the radiator completely, it would still get some airflow. I'm wondering if the block guard is impeding flow, but is shouldn't as it still has holes in it.

IDK, I hope it's the sensor. After $1k for that damn clutch, I'm tired of paying for shit, I just want to drive.

*edit I looked up the part numbers, and they are both the same.

Yez i have a completely virgin z3 longblock. And im also on the ktuned halfsize 2 core aluminum radiator, ktuned fan w/shroud, and ktuned coolant port with radiator cap on the side of the head. I kinda have a feeling im hitting some bubbles or the dam thermostat is getting stuck but it doesnt explain why this only happens in the daytime only, at night after wot the most itll hit is 202 for once and after that immediately cool back down to 190. During normal operation the temp hever goes pass 195 but once on the hwy its totally diff. My fan is working i have the force fan tep set to 190, will maybe lower that down once i install this new mishimoto thermostat and bleed the cooling system again and see what happens, but yea are your fans working?

And im on the z3 water temp sensor, i hope i dont need my a3 one back.

[monjarassi]

No problem, I do what I can to :ephatch:

Something hit me as I was about to go part researching, I had this problem with my RX-7, I know it's a long shot but before you two start throwing money at something try this simple procedure first just to have peace of mind. I know both of you have built setups so this will apply.

The RX-7 would run normal city driving and below 50 MPH, but once cruising at highway speeds my temps would go up to 200*F (on a rotary you don't want it that high if you're not boosting). It had me puzzled because I thought my coolant seals were gone but I wasn't burning coolant.

Long story short, it ended up being a leaky hose that cracked at the clamp. When the engine had load on it, it caused the water pump to pump at a higher PSI (highway speeds + wind drag = more load than normal city). Go to your local parts store and rent/buy a coolant system pressure tester to make sure you dont have any leaks. Make sure to get the import radiator cap adapter for it too.

If this doesn't work, make sure you guys filled the coolant correctly in accordance with the factory service manual. Try these things before you gotta go tearing off the intake manifold and replacing thermostats and what not.

Now I'm gonna go compare temperature sensor part #'s.

EDIT:

Oh forgot to mention,

The reading K-pro gets (ECT*) is from the bottom of the radiator once the coolant has passed through it and ready to go back into the engine.

I have an aftermarket water temp sensor installed where the AAV used to be (directly above the exit coolant port) and it tells me the temp of the coolant coming right out of the engine so it's much more accurate than what the sensor at the bottom is doing. This way I can catch overheating way before the radiator overheats itself trying to cool off the engine.

So from what you guys are telling me, if your Kpro said 220*F, then your engine must have been around 230-245 range and that my good friends is no bueno. When my autometer reads 218~ my kpro reads 206 (when fan kicks on).

well on our motors (z3's) the temp sensor is on the head next to the cam sensors, im running also the ktuned hoses and have no leakes at all, i havent pressure tested the system but will. I have no sensors on my aftermarket radiator in case you wondering.

[gtolio]

Have you guys pulled over and checked to see if the thermostat is functioning during the issue?

If it is in fact working, I would bleed the system again to make sure there isn't any air in it.

[monjarassi]

Have you guys pulled over and checked to see if the thermostat is functioning during the issue?

If it is in fact working, I would bleed the system again to make sure there isn't any air in it.

i have in both occasions and the upper and lower hoses feel warm dam silicone hoses dissipate the heat very well and cant really tell.

p.s. i will be bleeding the system again tonight and see if any results

[gtolio]

i have in both occasions and the upper and lower hoses feel warm dam silicone hoses dissipate the heat very well and cant really tell.

p.s. i will be bleeding the system again tonight and see if any results

Can you feel coolant moving through the system on the outside of the hoses?

[monjarassi]

Can you feel coolant moving through the system on the outside of the hoses?

yes i assume its moving cause it only happens when constant hwy speeds at daytime, not night

[02_epdriver]

k24z1/k20z3

Thanks for the update I guess I need to go back and read a little bit more. Thanks for correcting me.

[sleepy ep3]

yes i assume its moving cause it only happens when constant hwy speeds at daytime, not night

That what is making me confused as well.

[monjarassi]

That what is making me confused as well.

dam i just want to solve this issue mann..

[sleepy ep3]

Check the coolant level after it hasn't been started in a while. I just checked mine this morning, and it was really dry! So after seeing that, I looked under the car, and saw a small puddle. The lower hose was dripping very slow. Put on new clamp, and ran it for a bit. It was still low, so I'm guessing that the heater core sucked up a ton of antifreeze. After putting in 1 1/2 bottles of water wetter an topping it off, temps seems to be more stable. I drove it to work today and had some highway time, seemed to be ok. I will go on an extended drive tonight, and see what's what and let you know. Like I said, I'm betting that once your initial top off flowed through all the components of the motor, you will need to add more. Btw, that water wetter shit is awesome. Seems to be lower, and running ok. Best of luck Monjarassi. ;)

[USAF EP3]

Check the coolant level after it hasn't been started in a while. I just checked mine this morning, and it was really dry! So after seeing that, I looked under the car, and saw a small puddle. The lower hose was dripping very slow. Put on new clamp, and ran it for a bit. It was still low, so I'm guessing that the heater core sucked up a ton of antifreeze. After putting in 1 1/2 bottles of water wetter an topping it off, temps seems to be more stable. I drove it to work today and had some highway time, seemed to be ok. I will go on an extended drive tonight, and see what's what and let you know. Like I said, I'm betting that once your initial top off flowed through all the components of the motor, you will need to add more. Btw, that water wetter shit is awesome. Seems to be lower, and running ok. Best of luck Monjarassi. ;)

See, and you guys started to freak out about the sensor LOL. It's all good fellas. Most problems are simple fixes, rarely does it build up to something bigger than that. This is how we do maintenance in the AF, we start with the little stuff and then work from there.

I'm glad my suggestion worked for you sleepy.

[sleepy ep3]

I'm a panicky guy, especially when a $10000 motor is at stake, lol

[monjarassi]

Check the coolant level after it hasn't been started in a while. I just checked mine this morning, and it was really dry! So after seeing that, I looked under the car, and saw a small puddle. The lower hose was dripping very slow. Put on new clamp, and ran it for a bit. It was still low, so I'm guessing that the heater core sucked up a ton of antifreeze. After putting in 1 1/2 bottles of water wetter an topping it off, temps seems to be more stable. I drove it to work today and had some highway time, seemed to be ok. I will go on an extended drive tonight, and see what's what and let you know. Like I said, I'm betting that once your initial top off flowed through all the components of the motor, you will need to add more. Btw, that water wetter shit is awesome. Seems to be lower, and running ok. Best of luck Monjarassi. ;)

i have my filler neck full when i check the coolant level in the morning, and im using that wetter shit and havent seen the results yet buddy

[sleepy ep3]

i have my filler neck full when i check the coolant level in the morning, and im using that wetter shit and havent seen the results yet buddy

Have you tried raising the front end on jack stands, and running it? Most forums I was researching said that the radiator has to be the highest point, and then you let the air "burp" out. Have you tried switching the thermostat out?

[monjarassi]

Have you tried raising the front end on jack stands, and running it? Most forums I was researching said that the radiator has to be the highest point, and then you let the air "burp" out. Have you tried switching the thermostat out?

wll i havent tried either or, but once my new mishimoto thermostat comes in ill re burp the system, just got back from doing 14lbs pull for my tuner, fawk this bitch goes, i love the dam tq steer

[sleepy ep3]

wll i havent tried either or, but once my new mishimoto thermostat comes in ill re burp the system, just got back from doing 14lbs pull for my tuner, fawk this bitch goes, i love the dam tq steer
I understand, half the time I'm scared to floor mine, and that's only at 12psi. Can't imagine what 20psi will be like. Hope to find out soon :mangel:

[monjarassi]

I understand, half the time I'm scared to floor mine, and that's only at 12psi. Can't imagine what 20psi will be like. Hope to find out soon :mangel:

itll be insane, i riden on my buddies fully built rsx at 29psi, fawk that thing puts you back in your seat if u know what i mean.