Is coolant temp 223f too hot?

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed Mar 19, 2008 6:48 am

Car was running hot today. Long story short, i plugged the laptop in to check and the ecu was reporting coolant temp of 223 degree's.

vrg3 · Post by **vrg3** » Wed Mar 19, 2008 6:50 am

Yes, that's too hot. It shouldn't ever get above maybe 205 degrees Fahrenheit.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed Mar 19, 2008 7:35 am

Even with the ECU reading 223, the gauge was at normal.

Story:
Driving to the bowling alley today, i look down and notice the needle awfully close to Red. I baby it down the road, the needle keeps rising. After a couple minutes, the needle plumits and returns to normal. About a mile later, the needle rises again but holds steady at about 3/4 the way up, nowhere near red but still above average.

When I reach the bowling alley, i shut the motor down and look under the hood for any signs of leaking coolant.

Then I plug in the laptop and start the car. The needle is at normal, the laptop reads 223. I let the motor idle and the laptop shows temps dropping as low as 206 but then goes back up to 223 before I shut it down and go bowl.

After bowling, I lift the hood and fill the coolant back up. It took almost a complete gallon to top it off. On the drive home, I carefully monitor the gauge and it never goes above normal.

This is the same type of shit that was happening before I pulled the motor and replaced the headgaskets. *sigh*

asc_up · Post by **asc_up** » Wed Mar 19, 2008 10:52 am

Hmmm I was going to say that maybe it was an air pocket, but if you had to add a full gallon of coolant I don't know...

How does your oil look?

All_talk · Post by **All_talk** » Wed Mar 19, 2008 1:20 pm

Maybe the thermostat, did you change it when you did the head gaskets?

Gary

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed Mar 19, 2008 4:46 pm

Yeah, new thermostat with the engine build... got the thermostat from SOA when I bought my engine gasket kit.

It seems to be a case of missing coolant. I would think it were thermostat problems too if I didnt have to keep adding coolant every 2 days.

Post by **Legacy777** » Wed Mar 19, 2008 5:51 pm

Yeah...sounds like you were low on coolant....i've experienced air pocket issues like that.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed Mar 19, 2008 6:27 pm

So, Josh... when that happens... does the sensor then read the temp of the air trapped in the system instead of the coolant resulting in a spike of the temp gauge?

I cant imagine my engine actually operating with the needle in the red... and then when the needle does return to normal, it drops real fast... I dont think coolant could cool that quickly but im not sure.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Thu Mar 20, 2008 9:46 am

So I before I left work today, i topped off the coolant. It didnt take much, maybe 1/2 a liter. Then I plugged the laptop in and kept it on Coolant Temp the entire drive home.

It stayed steady at 180 degree's most the drive. The highest it got was 199 but never passed 200. I live about 8 miles from home, i would say it was at 199 at mile 4, and by mile 7 it had settled back down to 185.

So yeah... that 223 I recorded yesterday was way high.

Arctic Assassian · Post by **Arctic Assassian** » Thu Mar 20, 2008 4:42 pm

Whats your radiator cap look like?

TheSubaruJunkie · Post by **TheSubaruJunkie** » Thu Mar 20, 2008 5:03 pm

Its brand new. I bought it at autozone tho, they looked up one for a '93 Turbo Legacy.

It looks like its silver with a red tab in the center you lift to relieve pressure. Been thinking of going to SOA and getting a new one from them though since it seems you can never trust aftermarket replacement parts these days.

Post by **Legacy777** » Thu Mar 20, 2008 5:31 pm

I'd recommend getting an OEM radiator cap.

The coolant temp sensor isn't really going to read air pockets that well, at least I wouldn't think so. You probably had some pockets of hotter coolant that caused the temp spike.

Arctic Assassian · Post by **Arctic Assassian** » Thu Mar 20, 2008 11:44 pm

The temp sensor is in a place that is not susceptible to bubbles, in the coolant crossover pipe, just before the coolant enters the engine.. The bubbles get trapped just behind the thermostat, creating a buffer from coolant and heat. Lack of heat and hydraulic pressure(from the coolant) causes the thermostat to stay closed. Because the engine and radiator are separated by the thermostat, the engine will be much hotter then what the temp gauge reads, and the radiator fails to cool the motor.

I think you need to bleed your system and try again. And get an OEM cap no doubt. Because you over-heated, you have to be uber-carefull to check for signs of headgasket failure. Our motors do not like to get hot, thats why they crack heads.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Fri Mar 21, 2008 12:26 am

Yeah im gonna be pissed if I blew a headgasket. I just replaced the head gaskets and got the motor in and running. Havent even got a full tank of gas through the new build and im still having trouble.

I guess I gotta search on bleeding the system and see if there is something im missing.

Post by **Legacy777** » Fri Mar 21, 2008 3:27 am

Arctic Assassian wrote:The temp sensor is in a place that is not susceptible to bubbles, in the coolant crossover pipe, just before the coolant enters the engine.. The bubbles get trapped just behind the thermostat, creating a buffer from coolant and heat. Lack of heat and hydraulic pressure(from the coolant) causes the thermostat to stay closed. Because the engine and radiator are separated by the thermostat, the engine will be much hotter then what the temp gauge reads, and the radiator fails to cool the motor.

I think you need to bleed your system and try again. And get an OEM cap no doubt. Because you over-heated, you have to be uber-carefull to check for signs of headgasket failure. Our motors do not like to get hot, thats why they crack heads.

That's not correct, coolant flows from the bottom of the engine, through the engine, up and out the crossover pipe and then into the radiator. That is a relatively high spot where air could get trapped, as coolant flows faster it'll move the air pocket to the vent spot that dumps back into the expansion tank.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Fri Mar 21, 2008 6:20 am

Yeah i was wondering about that. The thermostat is at the lowest part of the engine while the thermo sensor is almost near the upper most part.

I can see how when my coolant gets low it could read a false signal. However, i still dont like the thought of my engine running that high.

Post by **Legacy777** » Sat Mar 22, 2008 2:54 pm

It shouldn't. The ECU regulates the temp between 180-200 deg F

Arctic Assassian · Post by **Arctic Assassian** » Sat Mar 22, 2008 7:18 pm

Yep I was backasswards. So what on earth caused this? It wasn't a bubble, was there just not enough coolant?

asc_up · Post by **asc_up** » Sat Mar 22, 2008 11:54 pm

Sounds like there just wasn't enough coolant. Especially if you initially had to add a full gallon to it.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Sun Mar 23, 2008 12:06 am

I find myself adding about a liter every 2 days.

I brought a coolant system pressure tester home with me from work. Im going to see if I can preasurize the system and check for leaks.

Murphy · Post by **Murphy** » Sun Mar 23, 2008 12:32 am

when you had the heads off did you have them pressure tested?

if you are putting in a 1/2 liter every day, its obviously going somewhere. does the car smoke at all?

Post by **Legacy777** » Mon Mar 24, 2008 6:37 pm

Pressure test the system and the radiator cap. I have the test pressures in a thread I started not to long ago in here.

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Is coolant temp 223f too hot?

Is coolant temp 223f too hot?