iriejedi Posted June 17, 2021 Share Posted June 17, 2021 I have a 2007 Outback and a 2005 Forester both of them don't like climbing the mountains in Colorado when it's especially hot out. Both of them also have automatic transmissions. Does anybody know of a high-flow radiator that has a tranny cooler in it as well? Stock isn't cutting it climbing the pass without my heater on. All I can find is high flow radiators for manual transmission vehicles. Typically their for Turbo, mine are not tubo. Jerry Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 18, 2021 Share Posted June 18, 2021 The radiator is not your problem. Ensure you are using the correct factory thermostat and you have proper airflow. What do you consider "not cutting it" ? What temps are you seeing and what evidence do you have that it's unsatisfactory? GD Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 18, 2021 Share Posted June 18, 2021 (edited) Sometimes, selecting a lower gear reduces strain on the engine and increases coolant flow. Make sure debris/dead bugs hasn't built-up between the condenser and the rad. Edited June 18, 2021 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
el_freddo Posted June 18, 2021 Share Posted June 18, 2021 Do you still have the engine cover fitted under the engine? This can have a huge effect on airflow through the radiator. There could still be other issues at play too - leaky head gasket could be one for example. Cheers Bennie Link to comment Share on other sites More sharing options...
lmdew Posted June 18, 2021 Share Posted June 18, 2021 My 2000 Impreza has the same issue here in CO when the temps reach 95+ F. Temp starts to climb if the AC is on and I'm going up hill in the mountains - heavy load. If I turn off the AC till the load is reduced, the temp will come back down. I have a aluminum aftermarket radiator in it. About 210K miles on the Impreza, Auto trans. The radiator does have the trans cooler built in. I had to adapt older Subaru fans to the radiator as the stock 2000 did not fit. Works well 99% of the year, so I have not pulled the thermostat or water pump. Link to comment Share on other sites More sharing options...
lmdew Posted June 19, 2021 Share Posted June 19, 2021 GD have you seen benefits of using Amsoil coolant? Which do you use, Passenger Car and Light Truck or Heavy-Duty Antifreeze & Coolant PRODUCT CODE: ANTHD1G-EA Thanks, Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 20, 2021 Share Posted June 20, 2021 While I'm sure the Amsoil coolant is excellent quality, and of course I'm an Amsoil dealer and use their oil exclusively in our engine builds, I can't imagine that there's any significant benefit to overall cooling system performance with Amsoil coolant. It's great for cast-iron engine blocks and preventing corrosion, etc - but there's no significant benefit to the Subaru platform..... It's not going to make any real difference in system performance. GD 1 Link to comment Share on other sites More sharing options...
iriejedi Posted June 25, 2021 Author Share Posted June 25, 2021 Still looking for a "high flow" radiator with an internal tranny cooler if anyone has a lead on these. One for an 07 Outback and one for a 05 Forester. Thank you for all the other advise and discussion although I did not hear a comment for the original question asking if anyone knows of where purchase this specific type of radiator for a N/A 2.5L with auto tranny. Colorado temps warmer than 85 degrees (usually 95 or more) climbing the mountain out of Denver on I-70 leave dead Subies along the sides of the road on a regular basis. This is a real issue for 2.5 L engines going up these mountains at the speed limit or higher. The air is less dense and rather dry as well at 6000 or 7000 feet pulling mountains. Link to comment Share on other sites More sharing options...
heartless Posted June 25, 2021 Share Posted June 25, 2021 6 hours ago, iriejedi said: Colorado temps warmer than 85 degrees (usually 95 or more) climbing the mountain out of Denver on I-70 leave dead Subies along the sides of the road on a regular basis. This is a real issue for 2.5 L engines going up these mountains at the speed limit or higher. The air is less dense and rather dry as well at 6000 or 7000 feet pulling mountains reduce speed a little, lower gear, higher revs will help a great deal. ie: take it out of overdrive! as for the radiator you are looking, probably no such beast for the automatics. 2 Link to comment Share on other sites More sharing options...
iriejedi Posted June 25, 2021 Author Share Posted June 25, 2021 (edited) 2 hours ago, heartless said: reduce speed a little, lower gear, higher revs will help a great deal. ie: take it out of overdrive! as for the radiator you are looking, probably no such beast for the automatics. I see there being value in Colorado for a radiator like that, I know the manual tranny/engine combinations have aluminum "racing" radiators and some of my friends use these to solve the issue. With all the dead Subaru's on I-70 from climbing the mountain roads, there is definately a market. And for just the dreaded head gasket problem I wonder if these could slow that failure rate everywhere. I understand that in most conditions these temperature behaviors don't exist (when I travel around North America I don't have problems), here in Colorado it simply does happen. Often actually... might I say. I've owned many 2.5L Subie's and all seem to struggle with the same issues on hot summer day's only. I wish they all could run hard like the old ej22 (1990 - 1998) that were impossible to blow up. Edited June 25, 2021 by iriejedi Link to comment Share on other sites More sharing options...
carfreak85 Posted June 25, 2021 Share Posted June 25, 2021 A couple thoughts on this: Those "dead Subarus on I-70..." Are those newer, well-maintained vehicles, or are they older 90's models? I'd wager they "died" from having older radiators that crack the plastic end tanks or a failed thermostat when flogged in extreme conditions (steep grades, high loads, high ambient temps, A/C usage, etc.). Radiators are a wear item. My WRX's radiator popped at 120k miles and we JUST replaced a cracked radiator in my dad's STI at 75k miles. These cars are durability tested by Subaru during summer in Death Valley, so they SHOULD have no problem climbing Eisenhower Pass in summer with the A/C on. You need to inspect all these components to ensure they're working properly. A dirt-filled or gravel-pelted A/C condenser will restrict airflow to the radiator, so put eyeballs on that, as well as the radiator. Make sure BOTH radiator fans come on. Ensure your cooling system is properly burped (Front end off the ground as high as you can safely get it and while the engine is running, massaging the radiator hoses until the thermostat opens and no more bubbles are seen in the radiator top tank.) If you're dead set on upgrading the radiator for piece of mind, buy an aluminum "racing" radiator for an MT, and add an external, auxiliary transmission cooler. Easy-peasy done. 1 Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 25, 2021 Share Posted June 25, 2021 A larger radiator will do nothing. It will probably make it worse as the fans will not be able to move as much air through the thicker core. GD Link to comment Share on other sites More sharing options...
iriejedi Posted June 25, 2021 Author Share Posted June 25, 2021 34 minutes ago, GeneralDisorder said: A larger radiator will do nothing. It will probably make it worse as the fans will not be able to move as much air through the thicker core. GD That's an interesting thought, thank you GD. I am curious then why race cars have thicker radiators? Link to comment Share on other sites More sharing options...
idosubaru Posted June 25, 2021 Share Posted June 25, 2021 3 hours ago, iriejedi said: some of my friends use these to solve the issue. Install one of those with an aftermarket transmission cooler for the ATF. If your car is handling this that bad then your ATF may be getting deliciously hot too. I've always disliked the shared radiator/ATF - I'd like a dedicated controlled cooler and ATF temp gauge. 3 hours ago, iriejedi said: With all the dead Subaru's on I-70 from climbing the mountain roads, there is definately a market. Let me translate that: "There's a ton of Subaru's in Colorado". lol That's a tiny, localized, 'seasonal' market relative to car part production. Link to comment Share on other sites More sharing options...
heartless Posted June 25, 2021 Share Posted June 25, 2021 3 hours ago, iriejedi said: That's an interesting thought, thank you GD. I am curious then why race cars have thicker radiators? they also have fans that are designed to work with those thicker radiators. the stock Subaru fans are not designed for that kind of application. and my comment above STILL stands - reduce speed, lower gear, higher revs. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted June 26, 2021 Share Posted June 26, 2021 (edited) They sell them because people buy them (bling). I have not seen one provide any additional benefit for a "race" application in terms of cooling. They are generally more reliable due to not being plastic and thus more resistant to damage from chassis flex due to hard corning, and having generally more longevity since their welded aluminum construction doesn't suffer from differential expansion and the embrittlement of plastics due to age. You still haven't answered my question in regards to what you consider "not cutting it" and what temps you are actually seeing. I don't start to worry about engine temp till it climbs past 250. For reference. Many vehicles don't turn on their fans till they hit the 220's. I recall many GM products not hitting high speed fan temp till about 235. GD Edited June 26, 2021 by GeneralDisorder Link to comment Share on other sites More sharing options...
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