June 25, 201510 yr Hi, I have a 2000 Legacy L Station. I just bought it this past January. For some reason about a month ago as I was driving down the Highway doing about 75 mph up a mountain, I noticed that the Temp gauge started to climb and stop just before it got into the red zone. Turning the heater on brought the temp back down to normal. On the other side of the mountain I didn't have any problems with the temp gauge rising again. Until about a week ago.... Now when I'm running at any speeds past 65 the temp guage will climb. But the moment that I slow down to 65 or under then temp starts to go back to normal. Both fans do come on. And I have noticed that when I come to a stop sometimes that the car sounds/feels like it's bubbling but when I look into the overflow tank there are no bubbles coming out of the hose.
June 25, 201510 yr Three things to look at (for now we will skip the ever fearful headgasket) 1- Radiator cap 2-Thermostat 3- Cooling system leak How is your coolant level?
June 25, 201510 yr Author Three things to look at (for now we will skip the ever fearful headgasket) 1- Radiator cap 2-Thermostat 3- Cooling system leak How is your coolant level? Coolant level is full. Overflow tank is at the fill line mark.
June 25, 201510 yr But, Is the radiator full? Another C-villian! We're multiplying on here... Edited June 25, 201510 yr by Fairtax4me
June 25, 201510 yr If the cap is bad it wont draw coolant back int the radiator. It chouldnt be full, should be at the hot or cold line.
June 25, 201510 yr Author But, Is the radiator full? Another C-villian! We're multiplying on here... Yes the radiator is full If the cap is bad it wont draw coolant back int the radiator. It chouldnt be full, should be at the hot or cold line. And it's in between the hot and cold lines in the reserve tank
June 25, 201510 yr try cleaning the dead bees out of the radiator ,some people have had a lot of debris collect between the a/c cond. and rad. have the radiator flow tested?
June 25, 201510 yr Try checking for leaves/dirt/dust/dead bugs stuck to the front of the radiator and condenser, as Texan suggested. Beyond that, I would suspect a faulty thermostat or partially clogged radiator.
June 25, 201510 yr yeah, could be a non-oem style t'stat in there now, or a bad t'stat. if you replace it, get OEM (or the oem Stant)
June 25, 201510 yr Author Ok just finished putting on a new Thermostat (from dealership), and Radiator cap (from dealership). Also while I had the car up changed the oil. I'm about to go on a drive and will post the results.
June 25, 201510 yr Author yeah, could be a non-oem style t'stat in there now, or a bad t'stat. if you replace it, get OEM (or the oem Stant) No it was definitely an OEM tstat.
June 25, 201510 yr dang - hoping it isn't HGs. if it overheats again, pull over and, with the engine running, see if either; 1. there are bubbles coming up thru the coolant in the overflow tank or 2. the overflow bottle is filled vey high or spilling over. (don't remove the rad cap on a hot engine!) Edited June 25, 201510 yr by 1 Lucky Texan
June 25, 201510 yr Author Well it's still an issue. Was driving on highway doing 75 mph with ac on and it took longer for it to happen but the temp went up to just before red. slowed down to about 60 and temp dropped. No bubbling sound with the new tstat in Edited June 25, 201510 yr by Baslyn
June 25, 201510 yr Well it's still an issue. Was driving on highway doing 75 mph with ac on and it took longer for it to happen but the temp went up to just before red. slowed down to about 60 and temp dropped. No bubbling sound with the new tstat in I had the same thing happen with an EA82 wagon. It turned out that the radiator was internally blocked. Try a Radiator flush first before replacing the Rad.
June 26, 201510 yr I had the same thing happen with an EA82 wagon. It turned out that the radiator was internally blocked. Try a Radiator flush first before replacing the Rad. Thinking same thing....the radiator is plugged up. Does the car's heater work really well...as in pumping out really hot air. If not, then it is possible that the previous owner dumped a bunch of radiator stop leak in the system. Result can be blocked radiator, and blocked heater rad unit. Previous owner may have had a head gasket leak, so dumped something in the cooling system to see if that would help. Things to think about.
June 26, 201510 yr Usually these symptoms are due to a system not holding pressure and the most common cause for not holding pressure is the radiator cap. Check the area inside the radiator where the inner gasket of the radiator cap seals to make sure there are no gaps or deformities. Check the rubber on the new cap to make sure it didn't come with a defect. A new cap should have fixed the issue. Maybe you still have a bubble in there.
June 26, 201510 yr Do you have an infrared thermometer? You can use that to check the radiator for "cold" spots. Its kind of tricky to do on these since the fans are in the way. You drive the car until it gets to normal temp, then check the radiator in several places for temperature variation in the core. Temperature should have a steady decrease from left-right or top-bottom depending on which way the core tubes run. (Horizontal or vertical) If you find a spot in the core where the temp drops drastically that indicates a clog in the core tubes in that area.
June 27, 201510 yr I'm actually suprised no one said to simply get an infrared thermometer and check the temp of the system in general. Have you had any other symptoms besides the gauge? It could be that your problem is actually in the temperature sender for the gauge (not sure if that's on the Coolant Temp Sensor or separate on that car).
June 27, 201510 yr I'm actually suprised no one said to simply get an infrared thermometer and check the temp of the system in general. Have you had any other symptoms besides the gauge? It could be that your problem is actually in the temperature sender for the gauge (not sure if that's on the Coolant Temp Sensor or separate on that car). Read the post above yours.#17
June 27, 201510 yr Read the post above yours.#17 Fairtax was referring to using it to specifically check the radiator for cold spots to identified a potentially clogged radiator. What I was referring to is verifying the gauge is actually reporting correctly. It's always a possibility the problem could be the temp sender unit or the gauge itself and the car isn't overheating at all. I've only seen that once myself (not on a Subaru) and don't think it's very common, but it's always a possibility.
June 27, 201510 yr I'm actually suprised no one said to simply get an infrared thermometer and check the temp of the system in general. Have you had any other symptoms besides the gauge? It could be that your problem is actually in the temperature sender for the gauge (not sure if that's on the Coolant Temp Sensor or separate on that car). Guage and computer use the same sender on this year. Symptoms don't sound like a bad temp sender. That would show up anytime. The OPs problem only happens on the highway.
June 28, 201510 yr Author Thinking same thing....the radiator is plugged up. Does the car's heater work really well...as in pumping out really hot air. If not, then it is possible that the previous owner dumped a bunch of radiator stop leak in the system. Result can be blocked radiator, and blocked heater rad unit. Previous owner may have had a head gasket leak, so dumped something in the cooling system to see if that would help. Things to think about.
June 28, 201510 yr Author Yes the heater blows hot like no other car I've ever owned. Also have had no fluid loss. Checked tonight before leaving work. Doesn't look like any damage to new rad cap. Edited June 28, 201510 yr by Baslyn
June 28, 201510 yr Author Also don't know if this is the same problem but for some reason the front passenger side plug wire keeps coming off the plug. Getting a knock sensor code when it comes off. Plug it back in, clear the code and it stays gone until it pops off again. I just changed all plugs and wires about a month ago.
June 28, 201510 yr Rockauto.com has good prices on radiators. They have a Denso for $105 (high quality OE manufacturer for most Japanese brands) Cheaper aftermarket brands for about $70.
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