Posted: 1/13/2010 10:11:00 AM EDT
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2006 Nissan Pathfinder If I start it up 10-15 minutes before going anywhere, when I get in to leave the temp gauge shows the engine warm but it's blowing cold air. After I've driven less than a mile hot air starts coming out. Happens every time. Any diagnostic ideas? |
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Quoted: I don't know about that one, but some vehicles will only blow out heat once the air reaches a certain temp. My two Crown Vics were made like that. Yeah, but I've let it warm up for 20 min before just to see if that was the case. It doesn't get that cold here, my old Lexus is usually GTG in about 6-8 minutes for example. |
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Almost sounds like the way a air bubble or something in the system acts, judging by how it takes some driving (and RPM fluctuation) to get the heat blowing. Not sure I would have the coolant vacuum out and all, but keep this in mind down the road if all else fails.
By the way, you shouldn't have to wait that long for the vehicle to warm up (not referring explicitly to blowing warm air, just in general). You really end up using more gas than necessary, but then again you'd want to be running at least a decent oil that doesn't have poor cold flow properties, naturally. I also wouldn't crank the car straight up and drive off, like I saw a guy in an Audi TT do this week when it had been sitting outside for 8 hours in 15-30* weather, either. If you mean that you are just trying to let the inside of the car warm up before you get in, then forget that comment. |
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Check the coolant level in the radiator or on the engine. The coolant expansion tank won't be accurate. If the level is right at the sealing surface or about an inch lower it's probably OK. If not, slowly and carefully top off the system. Make sure it is completely full. If there are any cooling system bleeders open them and let the air out and continue to top off. If there is a heater hose that is higher than the engine you can remove it to let air out. If you need to pour coolant in the hose till its full then reinstall. A low coolant level can cause no heat at idle then the water pump will circulate coolant as the engine rpms go up. Run the engine till hot and check for any leaks. If you need to wash the engine with a garden hose then drive around till the engine is dry then look for colored coolant leaking. You may need an inspecton mirror and flashlight to see the water pump bleed hole. If this doesn't work flush the cooling system by putting flush in the engine and drive around for 20 minutes. Let it cool till you can open the system safely. Thoroughly flush the the cooling system forward and backward. Drain the radiator and the engine block if the block plugs are accessable. Remove both heater core hoses and flush the core back and forth. Install a new factory thermostat making sure it is installed in the proper direction with the bleed hole at the top or the recommended postion. Now its time to refill and bleed the cooling system. Find out what the cooling system capacity is and divide by two. This is the amount of straight coolant you want to pour in the engine first. Add an extra quart of coolant and some conditioner and top off with distilled water. If you have a vacumn operated heater valve or heater door servos make sure the vacumn is strong and the lines are properly installed. If there is a vacumn reservoir make sure it has no cracks. Mice love to chew on the vacumn lines. Some suggestions good luck. |