Salsa91 Posted November 6, 2013 Share Posted November 6, 2013 My heat works great, but only when I'm driving at a constant speed. When I'm at a stoplight, the heat goes away and I start getting cold air. Could it be a bad thermostat? It also takes forever to get warm air after the engine coolant temp warms up Link to comment Share on other sites More sharing options...
monkeyposeur Posted November 7, 2013 Share Posted November 7, 2013 Do you have an aftermarket thermostat? OEM Subaru thermostats are generally accepted to the the only good option. Have you had your headgaskets replaced yet? Link to comment Share on other sites More sharing options...
Salsa91 Posted November 7, 2013 Author Share Posted November 7, 2013 I just bought the car on Saturday and previous owner said the car started to overheat so he had the thermostat and water pump replaced as well as the coolant Link to comment Share on other sites More sharing options...
monkeyposeur Posted November 7, 2013 Share Posted November 7, 2013 Hopefully he used an OEM tstat. I'm not trying to rain on your parade but if your head gaskets haven't been replaced then it is only a matter of time before they go. Unfortunately the 2.5s such as yours have head gaskets that are prone to failure. The good news is that it isn't too hard of a job to do even for an inexperienced DIYer. I'd find out if the tstat is OEM and have a hydrocarbon test done on your coolant to rule out any headgasket issues. Look for bubbles in the coolant overflow tank as well as floating gunk, white smoke coming out of the tailpipe. Is the car overheating on you at all? It could also simply be an air bubble in your coolant system so I would try purging the coolant system a few times.. Link to comment Share on other sites More sharing options...
Salsa91 Posted November 7, 2013 Author Share Posted November 7, 2013 How can I tell if the tstat is oem? Coolant seems to be normal and no gunk in the oil dipstick tube. I've had no ever heating issues yet. Is there a write up for the head gaskets? Link to comment Share on other sites More sharing options...
IrishLt Posted November 7, 2013 Share Posted November 7, 2013 Well you could have a restricted/blocked heater core. I'd give it a good flushing, see what that does for the problem. Just to check, there's no overheating since you bought the car? As monkey said, our 2.5 engines factory headgaskets were screwed up so that automatically comes up with trouble shooting as a possibility unless it's already been addressed. How many miles are on it, if you don't mind my asking. Link to comment Share on other sites More sharing options...
Salsa91 Posted November 7, 2013 Author Share Posted November 7, 2013 164,xxx with an auto behind it Link to comment Share on other sites More sharing options...
monkeyposeur Posted November 7, 2013 Share Posted November 7, 2013 Easiest eay to find out would be to get the service records from the PO, otherwise you have to remove it: http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/26238-draining-replacing-coolant-thermostat.html A nice OEM tsat from the dealership will only run you $26 or so. There are lots of head gasket DIYs all over the forums. But don't stress out yet, lol. I could way off base. Link to comment Share on other sites More sharing options...
Idaho subaru Posted November 7, 2013 Share Posted November 7, 2013 Well, you could have gotten lucky, and the original overheating problem could have been water pump/ thermostat related. Assuming that was the problem, and it now no longer overheats, it now sounds like it could be a flow issue. At low rpms, the water pump isn't pushing as much water as it does at high rpms. So if the coolant is low, at low rpms there isn't enough coolant flowing to flow through the heater core, but there is enough to flow through the engine and keep it from overheating, in theory anyway. I know this how I knew I needed to add coolant to my old Chevys. Since engines are fairly universal, that theory should work for any car right? There a few 'ifs' though. Most notably, if the water pump or thermostat were the original problem. Lets still say it was and they were replaced. The current problem is likely low coolant with air in the system. Do a search for 'burping' for ideas on how to fix that. Another 'if' would be if the thermostat was replaced, was it replaced with a subaru thermostat? It is generally accepted that aftermarket thermostats are quite inferior. It could possibly contribute to flow issues. Another 'if' would be if the water pump was replaced, was just the water pump replaced? and no timing components? I have not done it, but it would seem difficult to do just the water pump without messing up the timing, and I'd be especially concerned with how the tension on the belt was both released and reapplied. So I'd throw out there, that maybe when the repair cost was quoted for the water pump, (and since most shops would probably include the timing kit as standard if you're going to do the water pump on a timing belt driven cooling system engine), I'd say that is about when the for sale went on it. Again though, just a theory. I'd probably research burping the system, replace the thermostat with a subaru one for good measure first, then work on refilling the system and getting all the air out. Those are easiest things to try. And other than checking the oil for water/air bubbles in the oil/ gray foamy stuff. To help rule out head gaskets, check the coolant overflow tank for floaters, or air bubbles while running and after it has run for awhile, and smell it, if it smells like exhaust fumes, welcome to the head gasket club. I have rambled long enough, let us know what you come up with! Link to comment Share on other sites More sharing options...
Salsa91 Posted November 7, 2013 Author Share Posted November 7, 2013 Alright thanks for the help. I'm glad you guts know more than me haha. I'm gonna look into it this weekend Link to comment Share on other sites More sharing options...
Kevlar_07 Posted November 7, 2013 Share Posted November 7, 2013 Could be air in the coolant system but, I sounds like a head gasket issue mine had a similar issue when stopped but the temp gauge went hot if yours is staying consistent i would bet on air trapped in the system. Like said above check the coolant res. for bubbles and or gunk floating on top. Link to comment Share on other sites More sharing options...
Salsa91 Posted November 9, 2013 Author Share Posted November 9, 2013 How do I get an air bubble out if it is that? TIA Link to comment Share on other sites More sharing options...
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