I have a quick question regarding the engine temp of a ´96 Legacy Outback. If anyone has read my threads before, they know that I've been complaining about my temp gauge not working. With seemingly excessive fuel consumption of late, I am wondering if the gauge is functioning optimally, but the engine is not warming up for some reason´. The gauge seems to bounce around the 'C' with it definitely staying on the bottom when I am on the highway. I also notice that I have plenty of heat from the heating system. When this problem began, I changed the therostat and the temp sensor (both original Subie parts).

 

The Q: Is there a quick-and-dirty to tell if the engine is coming up to temp? I have received some response from an European counterpart here regarding disconnecting the lamda sond, which I haven't gotten around to yet. But are there any other obvious ways to check?

 

Thanks!

 

 

Sweden

Maybe....remove rad cap on cold engine, start engine, use kitchen/meat/BBQ thermometer to measure coolant temp. When the fan comes on is probably max temp (or close) for the rad. That will probably be lower than the thermostat value (if the thermostat is a 195 deg.F t'stat - maybe the water would be a little less cause the t'stat is on the bottom and the water will have been cooled by the rad befroe returning to the engine.) You could compare your numbers to those from another sube. Also, there are handheld infrared, remote reading thermometers available. I'd expect parts of the engine to be several degrees above the t'stat value. And of course the exhaust headers would be quite warm. Never done this myself. Plese post back your results. Low engine temp in most modern cars will lead to poor fuel economy.

Does the engine feel warm or hot? Rest a thermometer on the engine block, engine off!, hopefully it will read around 80-90 degrees centigrade. Is the cabin heat working? I expect you need it at this time of year!!

 

Does the top radiator hose get hard and warm? Indicating correct pressure in the system and flow into the radiator?

Yeah Texan! Good point. If the temp is too low the lambda sond is ignored, and the engine will continue to run rich to warm up.

One thing I did try a few years back, when this problem first developed, was start the car and let it run for about 30 minutes in the garage w/o touching the accelerator. The temp gauge came up to the "normal" operating range because the fan didn't activate.

 

Also, I do have sufficient heat to the cabin, which makes me all the more puzzled...

 

 

Sweden

Hmmm, there are two temp sensors. One for the ECU to determine mixture, and one to relay info to the dashboard. Which did you replace?

On my 96 Brighton, there is only one coolant temp sensor relaying info to the ECU wich in turn activates the temp gauge.

I am absolutely certain of the first part (only one sensor) but I'm only speculating as to how the gauge is activated.

I'm not sure if there is one or two. I actually bought the sensor at the dealship in Minnesota, since the car was bought there (I bought it when I was back on vacation). But the dealership seemed to show only one sensor. Irregardless, it had no impact on the temp gauge issue.

 

Sweden

On my 91 Legacy L there are two temp sensors. One 2 prong sensor which has a connector and is used by the ECU. There is another, smaller one mounted at almost the same location which is used for the temp gauge.

The one that I bought screwed into the engine somewhere (I didn't actaully install it).

 

Sweden

Yes it's under the right side (passenger) intake manifold and a little hard to get at.

 

Some people here might know this more exactly (777 or Alias) but it seems possible that on the EJ22 engine at least, the passage from two sensors to one was made in 1995.

coolant temp sensors

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2477.JPG

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2505.JPG

 

Not sure when the change was made to one sensor however....but you should be able to look at the pics and then your car, and determine if there's two sensors or one.