Eng coolant temp sensor location
 

Can someone tell me where it s located?

At Buttonwillow and the sensor is getting hot (not the coolant) causing limp mode.

David

How do you know it's the sensor getting hot and not the coolant if you don't know where the sensor is..?

By using common sense....

Temp gsuge stays at half then shoots to red. 30 sec later back to half

I'm not following. That's not using common sense at all, lol. What makes you think this is the sensor getting hot and not the coolant? This makes no sense at all..

Do you have a real gauge or reading from the ECU? What are the temps while driving and while idling when the car is showing overheated?

The gauge on the dash is essentially a fake gauge, it will only show cold/normal/hot. It doesn't linearly scale with the temperature.

Your temps are probably within operating range, then barely climbing outside normal operating temp and the gauge goes up to the red, then back down to normal where it goes back to the middle. Most modern cars are like this. The gauge is dumbed down for the masses.

I have the aim solo dl now.

Reading 185-190 2 minutes after.

Pretty sure its the radiating heat from the header, engine and everything else.
No smell of coolant or any other symptoms.

I have a fbm radiator also so it shouldnt overheat after 3 hot laps.

So, the location?

http://www.ft86club.com/files/BRZwiringi.pdf

page 38 C35 E.F.I. Engine Coolant Temperature Sensor looks like under intake manifold

can you monitor coolant and oil temps with torque or scantool or other device ?? might be dash guage fault or wiring, air pocket ect.

It's towards the rear on the engine.

Did you just recently install the radiator?

Edit- Your sensor isn't getting heat soaked and giving you false readings. Your car is overheating. The gauge on the dash is going up the the red and back down to normal because of the resistors placed inline with it to scale it back and keep the needle steady all the time when it's in the normal operating temperature range. If you were to watch a linear or digital gauge and compare it to your dash gauge you would see what I am talking about.

Ahhhh! All simple seeming questions turn out to be more complicated.

You have replaced part of your coolant system, now are having these symptoms....

Sounds like you have a large air bubble in your system.
As the bubble(s) pass the temp sensor, it is swinging all over the place.

Thank you very much.

Exactly what I neded

I'd recommend bleeding your system man..

If your exhaust and block are getting hot enough to effect your sensor, which probe is INSIDE the engine block and 12"+ from the exhaust piping.. you would have much much bigger problems (like a car on fire).

I would bet quite a bit you are dealing with an air pocket like others mentioned. Seen it before plenty of times. Try turning the heat and feel the air coming out of the vents, if there is a point where it starts to not be so hot, it's an air pocket.

The ECT sensors aren't very complicated and I don't think I've ever seen one fail due to heat.

Tried all that.....

Will try again.


Temps got to 224 after 5-6 hard laps.

This. This is exactly what usually causes the symptoms of what OP is seeing.

+1 for air pocket

If you have bled system of air

Any chance of a restriction/partial blockage ?

Kinked pipe , thermostat not opening correctly, do you have one of those heat exchanger oil coolers ? that go into a radiator hose restricting flow or causing waterpump to cavitate.

do you have underdrive pulleys

check drive belt tension

I would bet it's either an air pocket or something wrong with the thermostat, and nothing to do with the sensor getting heat soaked.

Full list of mods done?

So here are a few things that come to mind:
1. The FA20 uses Subaru Super Coolant (Blue). Any coolant you use should have similar cooling properties.
2. The bleeding procedure needs to be followed otherwise your sure to have cooling issues. Procedure is as follows:
- TURN A/C switch to off
- Fill through filler neck till full
- Pump radiator hose several times and add coolant if it drops
- Open the bleed valve located on the heater hoses near the firewall
- Add coolant as required
- When coolant comes out of bleeder close it and top up filler neck
- Fill reservoir tank to the full mark
- Tighten radiator cap
- Start engine and rev it a few times (don't let it warm up too much as you need to do the next step before thermostat opens!)
- Remove radiator cap, and open the bleed valve and fill with coolant and keep doing the procedure above until coolant does not drop
- Ok now turn on the heater to max hot and fan low and run the engine until the radiator fan starts and stops
- You want to wait now for the coolant to drop safely so that you can remove the radiator cap and check coolant level. Add coolant if needed.
- If you hear gurgling sound from the heater side it means you did something wrong and you have to redo the whole process.

Yes it might seem like a lot of work, but it really is imperative to get all air out of the system.

Pretty sure @stugray nailed it. Get the nose up a little and get that air bubble out

Nope
Nope
Nope
Nope

All the obvious have been checked or I wouldnt have posted here....

Its fine on the street or light load on track.
When you hammer it, second lap, ck eng light/p0117

D

If it was the tstat, it would happen irregardless of load

I admitt we are all guessing here mate but we also dont know what mods you have and what the history is.

Assume your boosted and reciently installed new radiator , as you say its fine on street and light track work but carnt cope with heavy work on track.

Would indicate sensor is ok and maybe it just carnt cope with a hard workout, what are ambient temps ? what boost are you running 15 psi plus ?

have you made any mods to front of car or airflow through radiator
have you removed or modified undertray ? vented bonnett or other engine bay venting ?

Yes supercharged. Very light boost, under 9.
No airflow mods (except the ic - which may be blocking)
Stock hood - no vents.
No mods to undertray
Oil cooler for both engine and sc.
Ambient 100 farenheit

Im gonna install a manual water temp gauge to get a better idea


Cheers

Are you currently logging the coolant temp? Does the log behave exactly like the gauge, or is it responding normally?

I don't have a logger at mo, but I used the AIM Solo DL for a couple of sessions, and it stayed in the 195 deg range. Gauge was normal.


I'm waiting for an ecutek cable, so I can log more.

you can log with a $10 ELM 327 from ebay & the Torque app.
Or for $140 you can log with a tactrix dongle/cable.
Neither of those require a Laptop to be connected to log.

Unless you have ecutek already and they dont allow third party OBDII logging. (I would have a hard time believing that)

Yea, I actually have that already.
I forgot, I've been very busy.




I will confirm, but I will bet my last dollar that one the street it won't go anywhere near the upper limit.


D

Hi,

Any update on this?

I'm throwing the coolant sensor code too and the wildly fluctuating temp gauge on the binnacle as well. Fan kicks in when the gauge flicks up to red etc.

My aftermarket oil and water temp gauges are showing stable and expected temps so I'm 100% certain this is a sensor issue. Planning to replace it.