SUBARU3 Posted January 15, 2016 Share Posted January 15, 2016 I am fairly new to driving my 95 Subaru in COLD weather. Being from TX, things just don't get that cold! Have one of my Subys in PA and have noticed weird things...maybe normal, about my 2.2. Car has 78K on it. 1) I have heard some gurgling in the heater core at times and was noticing the fans were on at idle with temps in the low 20s. Like the thermostat was not opening. (I think the fans were preventing the thermostat from ever opening in the cold weather). The coolant was low, so I added coolant. It then proceeded to blow it all out after driving a good bit! I then did a quick coolant change and did switch out the thermostat just in case..(it was good though). 2) Now I notice the fans turn on when needed, like after idling a long time. So I assume the fan /temp sensor is good. But maybe it's bad? However it seems that it takes FOREVER for the bottom radiator hose to get warm and thermostat to open in really cold weather and also the system never really pressurizes in these cold temps. I also still hear some heater core gurgling, but less now. Interior heat ALWAYS works, but I'm sure that is the bypass system. Is it just normal for Subarus to warm that slowly in really cold weather.....and not really pressurize? Maybe it pressurizes at highway speeds, dunno. Car runs/drives fine. I know the thermostat configuration and location, lend it to staying cold longer. Also temp gauge is always in the normal range after warmup. Just confused about this system and cold weather operation. Thanks! Todd Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 15, 2016 Author Share Posted January 15, 2016 Also, never overheated, (temp gauge is always steady) and no bubbling seen in radiator with cap off, or in reservoir with cap on. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 15, 2016 Share Posted January 15, 2016 How much did you spend on a replacement thermostat? If you bought a cheap to middle grade, that could be your continuing problem. Subarus need either an OEM thermostat, or the most expensive one you can find at a store, or on line. I would also question the radiator cap, and wonder if it is able to keep pressure in the cooling system. Good that you are not seeing bubbles in the coolant reservoir. That is a dead give away that you would be having head gasket trouble. Head gaskets usually don't go bad on a 2.2 motor, but it can happen, as I had a 91 Subie with the 2.2 that blew the head gasket, and blew coolant bubbles. 1 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 15, 2016 Author Share Posted January 15, 2016 It was a Subaru OEM replacement thermostat, no junk. Oh, I also replaced the cap. However, when I tested the original thermostat, it tested OK. I'm just thinking the cold temps have alot to do with it. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted January 15, 2016 Share Posted January 15, 2016 Hm a few random thoughts: if you have a scangauge or similar device you can monitor what the ECU thinks the engine coolant temp is and see if it seems reasonable throughout operation. In cold temps idling if the heater is on high it may be rejecting enough heat that the thermostat never really has to open much, so the lower hose doesn't get warm, or, even if it does open a bit, not having much flow through the radiator, it may be cooling it down substantially so that the lower hose doesn't feel hot. In my '96 I did a few years ago hear that gurgling in the heater core, but after making sure all the air was out of the system it went away. Also obviously if it's set to any of the defrost related settings it will be trying to run the a/c also (if equipped) which may cause the fans to run or cycle. 1 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 15, 2016 Author Share Posted January 15, 2016 The heat is always good, so you may be right in that the heat is taking the load off the engine and keeping it cool. That thermostat on the bottom of the engine is not in a position to get hot quick. Am I correct in saying that the coolant has to get HOT, not just warm in order for the system to pressurize? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted January 16, 2016 Share Posted January 16, 2016 When you say pressurize, how do you mean, i.e. the rad hose feeling 'hard'? It's kind of subjective but I'd say the few times I've checked mine maybe above 150F coolant temp the hose feels a bit firm. If you don't think that's happening the rad cap could be suspect as Rooster mentioned. I've had trouble with the genuine radiator caps not lasting more than a couple years. A quick test is with the engine off and the lid popped on the overflow, squeeze the upper rad hose hard. If you feel the hose go soft and hear/see coolant going into the overflow then there's an issue with the cap. Sometimes cleaning it and underneath the gaskets will make it seal better, other times it just won't. The thermostat is basically relying on the return from the bypass and heater core to know when to open. That's the main flow that's going across the thermostat springy part. Also the temp gauge is a bit funny, it's made to more or less just stay in the middle if it's in the normal operating range. Only if it gets quite too hot or too cold will the needle be much outside of that. I think they made it that way so people wouldn't worry about it too much. A scangauge or similar is the way to see the real temp the ECU thinks it is seeing. 1 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 16, 2016 Author Share Posted January 16, 2016 I think the top hose gets a bit firm about the time the fan turns on. I think I will try with the heat OFF and see if that speeds things up. I think the cold ambient temps and the heat on, suck all the heat off the engine! I will try another rad cap too and your test. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 16, 2016 Share Posted January 16, 2016 (edited) Yes, these engines do take some time to get all of the coolant warmed up when it's very cold out. It has been in the mid 20s in the mornings here lately. My 95 gets to operating temp in about a mile and a half, I get some amount of heat before I get to the end of my street (1/4 mile) but it takes another 10 miles to get the heat up to full blast hot. The heater cores on these can sap quite a bit of heat from the engine when it's trying to warm up. Gurgling/trickling in the heater core is always a sure sign of a low coolant level. When you refilled the system after installing the new thermostat, how much coolant did it take to fill? Should be able to pour in about a gallon and a half. If it was less than a gallon there is still air in the system. Edited January 16, 2016 by Fairtax4me 1 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 16, 2016 Author Share Posted January 16, 2016 I think I have the coolant full, but I will recheck that level again. I have found that the car will not pull back coolant from the overflow during cool down, unless it actually pushed some out. So what is the absolute BEST way to burp/bleed/belch these cooling systems? Todd Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 16, 2016 Share Posted January 16, 2016 I think I have the coolant full, but I will recheck that level again. I have found that the car will not pull back coolant from the overflow during cool down, unless it actually pushed some out. So what is the absolute BEST way to burp/bleed/belch these cooling systems? Todd I know that it helps to have the front of the car elevated higher then the rear of the car, when adding coolant. Also, open, or fully remove the vent screw located on top, at opposite end of radiator from where you add coolant. Fill, then wait a bit for coolant to drain down, then add some more. After driving for a day or two, with engine cold, remove rad cap to see if you can still add additional coolant to the rad. Also, add more coolant to the over flow tank, if it is low. 1 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 17, 2016 Share Posted January 17, 2016 I usually fill the block through the upper radiator hose, then fill the radiator with the bleeder screw open. 1 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 17, 2016 Author Share Posted January 17, 2016 I don't think the 95's have a bleeder screw. I will look again. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 17, 2016 Share Posted January 17, 2016 Top of the end tank on the right side. Just looks like a plastic casting on top of the radiator but it has a + in it for a philips head screwdriver. Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 17, 2016 Author Share Posted January 17, 2016 Ahh...I found that on my Legacy....but the 95 Impreza's don't seem to have it sadly. (Both have the stock radiators). Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 18, 2016 Share Posted January 18, 2016 Impreza doesnt need a bleeder screw because it uses a vertical core (end tanks are on the top and bottom) and the fill cap is on the right side just a few inches from the upper radiator hose. Legacy filler cap is on the left, opposite of the upper hose, and the coolant you pour in has to go through the small tubes in the core before it can drain into the block. In order for it to get into the block it has to push the air out, and when the end tank on the filler side gets full of coolant it causes an air lock. No air out, no more coolant in. Eventually the coolant will get into the block through the jiggle dohickie on the thermostat (assuming the car has a stock thermostat) but that takes several hours because only a small trickle can get through there. The bleed screw allows that air to push out which allows coolant to flow into the block through the upper hose. That still takes a bit of time, which is why I prefer to fill the block through the upper hose first. 3 Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted January 18, 2016 Author Share Posted January 18, 2016 Fairtax....that make absolute sense! Thanks for that explanation and now I see why on Legacy, it's easier to do the top hose fill, vs through the rad cap. Quote Link to comment Share on other sites More sharing options...
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