idosubaru Posted January 25, 2008 Share Posted January 25, 2008 some update on my mysterious cooling issue. no coolant loss, car runs and drives fine and does not over heat or run hot in the winter. what i've noticed this winter - when idling the "heat" will get rather cool, just warm, not hot at all. if i raise the RPM's while sitting still the heat immediately gets hot coming out of the vents. normally i would just think the heater core is clogged...but since it does run too hot in the summer could something be related here? EVERYTHING cooling related has been replaced except the heater core. new thermostats (multiple times), new radiator, flushed out new radiator, radiator worked fine on another XT6, new Subaru hoses, new water pump. so.....could this be a case of a bad water pump? is that possible for a water pump not to move enough fluid? it's a new Paraut water pump from rock auto. Quote Link to comment Share on other sites More sharing options...
[HTi]Johnson Posted January 25, 2008 Share Posted January 25, 2008 Air bubble? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2008 Author Share Posted January 25, 2008 Johnson']Air bubble? definitely not. heater core flush is in order though as connie mentioned on the xt forums. that would tell for sure if it's heater core related or poor flow related. with my hot running issues on hot summer days i'm expecting poor flow....or "hoping"??? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 25, 2008 Share Posted January 25, 2008 Even with the heater core completely clogged, it shouldn't cause any overheating. Have you verified that your temp gauge is reading correctly? I like those laser thermometers..... I had a clogged EA82 core due to some "headgasket repair in a bottle" that didn't work at all. After I replaced the head gaskets, the engine ran perfect and the temp was great - just no heat at all till I replaced the core. GD Quote Link to comment Share on other sites More sharing options...
Numbchux Posted January 25, 2008 Share Posted January 25, 2008 mine would do that when my radiator was leaking. and I think the biggest reason was the system wasn't pressurizing. you say you got a new radiator....but how's the radiator cap? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 25, 2008 Share Posted January 25, 2008 I agree - sounds like there's pressure problems and some of your coolant is vaporizing - thus the no heat situation. Coolant vapor doesn't transfer heat in the core. Perhaps some dye and a UV light. GD Quote Link to comment Share on other sites More sharing options...
screwbaru2 Posted January 25, 2008 Share Posted January 25, 2008 Grossgray, After I read your post I thought water pump also but, I reread it and noticed the "many times repalced themostat". I'm thinking maybe after many times you got a bad one. It's cheaper and easier than a water pump or heater core. If nothing eles you got it out of the way as a cause. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2008 Author Share Posted January 25, 2008 everything has been replaced except the heater core - radiator cap as well...more than once too. i'm positive it's not the thermostat. What is a good way to verify temps? Install another gauge (not a huge fan of that idea)...laser temp gauge, i've always wanted one of those. how would i use it? when, what part of engine, what temps am i looking for, etc? the temp gauge is very consistent...it shows cool when my cabin air temps are cool and goes up when climbing a mountain...it's very consistent, predictable, in the same range as the other XT6's i've owned (which is a lot), goes up with the A/C on. but i'd like to check. dye and a UV light -there's no coolant loss and i've never done that before. what would i be looking for, what would it show? for the past year and a half i keep thinking the head gaskets will finally show themselves, but that isn't the case. i've put 30,000+ miles on this thing and drive it all over the place. noticed while driving - when coasting down a hill (not under load).....my air temps cool down significantly....then when going up a hill it gets nice and toasty hot. flow or pressure problems... Quote Link to comment Share on other sites More sharing options...
Numbchux Posted January 25, 2008 Share Posted January 25, 2008 ok...my next guess is water pump. you say you replaced it.....what did you replace it with? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2008 Author Share Posted January 25, 2008 i replaced it with a Paraut pump from rockauto.com. now that we're talking about it the car was running hot before i replaced the pump, it was running hot when i got it. i assumed it was old radiator/fan relay related back then. the fan relay was shot and the fan wouldn't come on. of course i replaced those and the issue never went away. so i'm probably fooling myself into a couple hours of work that won't fix it. i think i have an extra radiator i could try but the radiator in it was new and was used in another XT6 i was driving that ran perfect. baffled, i'm thinking it's got to be a minor leak somewhere/somehow. i just checked and it's full of coolant....but it has to be a leak somewhere to be doing this. Quote Link to comment Share on other sites More sharing options...
Bucky92 Posted January 25, 2008 Share Posted January 25, 2008 Gary...are you going by the stock guage or do you have an aftermarket in it> Just wondering cause I went through so much with mine and it turned out to be just a faulty guage. Huck zapped it with his lazer thermometer and showed the car to be running at the right temps to even alittle cool. I know I have but havent instyalled yet..and aftermarket in mine for my own piece of mind. Just re read post..I would zap it with a lazer and see what its running at. With everything you have swapped out ..if it is truley running hot that only leaves the radiator pretty much Quote Link to comment Share on other sites More sharing options...
Numbchux Posted January 25, 2008 Share Posted January 25, 2008 ^ I would agree, except he's not getting any heat at idle. which means there isn't enough circulation through the heater core at idle. which is the symptom that I'm focusing on. if they're independant problems (i.e. it's not really overheating), then I'd say your heater core is clogged. but if your radiator is good, and the system is pressurizing properly, you could completely bypass the heater core, and still run cool. also, circulation through the heater core is not restricted by the tstat, so that's ruled out. only 2 things I can think of that could cause that, is the water pump itself isn't pushing enough coolant around until the rpms come up. or the system isn't pressurizing. if it's not leaking AFAIK the only way for it to not pressurize is the rad cap. EDIT: I just reread your original post....sorry, you already mentioned what kind of pump it was.... anyway, you also asked if it's possible for it to not move enough coolant. and it's very definitely possible. the water pump on the motor that came out of my loyale and went into my blue lifted wagon was like that. the car would stay cool on the freeway, but sitting still and at idle, no heat, then the motor would overheat, and the radiator was barely warm to the touch. only thing I replaced was the pump itself (all hoses, tstat, radiator, etc. were all reused), and the problem went away 100%. which brings up another question. when it's doing this, have you checked the temp of the radiator? is it getting hot? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 26, 2008 Author Share Posted January 26, 2008 all stock connie, no aftermarket stuff. laser temp guage is definitely on the list. i think radiator and hoses are getting hot.... i remember checking them to see if i could tell if the radiator wasn't flowing right. but it hasn't overheated since the fall...back when it was hot out last, so i'm relying on memory. I went through so much with mine and it turned out to be just a faulty guagewas your gauge reflective of what the engine and heat were doing and in the normal XT6 ranges most of the time? mine is predictable as a sunrise. was your quirky and unpredictable or predictable? another observation today....eventhough it's cold out and it never overheats...it did drift up above normal only after start up, warmed up, then dropped back down (remember i've owned 20+ XT6's i know exactly how they go)...went above normal, then drifted back down to normal. drove awhile on the highways, got off to get a bite to eat and it did the same thing when i restarted it...car already warmed up...temps drift up above normal...then back down and never go up again for the next 2 hours at highway speeds and driving around town. it never went above normal after dropping back down from the above normal (1/2 way) mark. drops back down and is rock steady? i have off tuesday i'll dig into this. i'll need to find a laser temp thing between now and then. what temperatures am i looking for, does anyone know? and where do i take them? Quote Link to comment Share on other sites More sharing options...
screwbaru2 Posted January 26, 2008 Share Posted January 26, 2008 I use my scanner to check coolant temp thru the ecu. "only 2 things I can think of that could cause that, is the water pump itself isn't pushing enough coolant around until the rpms come up. or the system isn't pressurizing. if it's not leaking AFAIK the only way for it to not pressurize is the rad cap." Except for the cap the above was the same as I thought after reading your first post. But if you are in doubt about the temp gauge then definitely check the temp before doing anything more. Also a hose will sometime collapse inside and restrict flow. Quote Link to comment Share on other sites More sharing options...
PoorManzImpreza Posted January 26, 2008 Share Posted January 26, 2008 I think u have calcification build up on the collant passage surfaces in the block and heads.. Kaz Quote Link to comment Share on other sites More sharing options...
zrbrat Posted January 26, 2008 Share Posted January 26, 2008 I'm not experienced with those engines so this might be a stupid question. Is it possible to accidentally put the thermostat in backwards? It sounds like a thermostat problem to me, but I'm no mechanic. Just trying to help. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 26, 2008 Share Posted January 26, 2008 what temperatures am i looking for, does anyone know? and where do i take them? Very useful tool - use one almost daily at work.... Take readings everywhere. At the temp sender will be the one you want to check against the stock gauge. Before/after the thermostat. Radiator inlet, outlet, and all around the surface to check for cold spots. Water pump. Heater core hoses. Etc. When you get enough data for a hypothesis of the problem, then start making changes to the system. UV dye is cheap, and you can get UV bulbs for maglite's and such. I have a flexi inspection tool set that came with a UV LED bulb. For like $10 you can get both the dye (multiple applications worth) and a UV light to check for leaks. You just dump the dye in and then check for glowing with the light while the engine is running. It's nice to steam clean the engine first, but not always needed. GD Quote Link to comment Share on other sites More sharing options...
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