Subaru Outback Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 11 of 11 Posts

·
Registered
1996 SUBARU OUTBACK
Joined
·
9 Posts
Discussion Starter #1
Just had headgaskets installed in my 97 legacy outback. Fired it up n withing a minute it pegged hot on guage. Put it on scanner and temp reads at 203 degrees. Could this be a coolant temp sensor? Help please. This is a 2.5 liter engine
 

·
Registered
2012 limited, white, no moonroof or nav
Joined
·
1,696 Posts
Yes thermostat is in correct- temp checked with temp gun and scanner
What part are you pointing the gun at, when you are getting 200 degrees? The only parts of an engine that should get that hot that quickly, starting from cold, are the exhaust headers. Even without coolant, the heads should not heat up that fast.
 

·
Registered
1996 SUBARU OUTBACK
Joined
·
9 Posts
Discussion Starter #5
Sorry for confusion, the car was running for a while when I took the temp. When cold the temp guage went to h instanlly
 

·
Registered
Joined
·
18,728 Posts
I believe the 97 has two coolant temperature sensors. They are mounted on the water (crossover) pipe on top of the engine. One of the sensors is for the ECM, the other is for the instrument panel temperature gauge. (See attached.)

If you connected a scanner that can indicate the engine temperature from the data at the OBD connector, then that's what the ECM is seeing from the related sensor.

If that was at 200 degrees (F), and a temperature gun was also used to confirm that temperature in the area of the sensors (on the water pipe), then the problem is with the temperature gauge sensor or wiring.

I would check to see if the wire to the sensor is connected. The temperature sensors are typically negative coefficient resistors, so that as the temp increases, their resistance goes down. In the case of the temperature gauge sensor, as the resistance goes down, the gauge goes up. If the gauge moves up to full HOT almost instantly, the sensor wire is likely grounded. It might have been left off when the engine was re-assembled, or the wire might have been caught when re-assembling and is crimped/shorted to ground.
 

Attachments

·
Registered
1996 SUBARU OUTBACK
Joined
·
9 Posts
Discussion Starter #7
Dead cold u fire it up n it rises to middle- and then in a min it shoots right up to hot
 

·
Premium Member
03 H6 OBW & 06 WRX Sportwagon
Joined
·
18,126 Posts
probably should check the system's voltage too.

weird
 
1 - 11 of 11 Posts
Top