#1
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Help pathfinder was overheating and now heater is just blowing cold air
2001 3.5 SE 230,000 miles
I drove my pathfinder on the highway(70 mph)for just over an hour with no issues. About an hour later I warmed her up and headed into town. About ten minutes into my trip (it's winter here) my heater began blowing COLD air, I immediately checked my gauge and was on H. I pulled over, checked under the hood and found NO signs of overheating. No sounds, No smells. I limped it to the auto store and added 1/2 gallon antifreeze, didn't change a thing. So I limped it home. At one point I became irritated and hit speeds of 45 mph, and my heat came back, but temp only dropped a hair. Finally got around to looking at it yesterday... 1st Replaced main thermostat and changed cap on radiator ---no improvement 2nd Made sure heater core was not blocked or leaking...it is not 3rd Burped air outta cooling system via radiator--no improvement 4th Changed out radiator and clutch fan and burped system------no improvement 5th Used my code reader to clear all codes from computer (forgot to ck for new codes before I cleared them, assuming code would come back) after clearing codes I let it run for 20 minutes or better, temp stayed at 196F, never hit H, but heater still blows cold air. So then I drove it down the road and back, never over heated but still blowing cold air. Only code now is P1135. This leaves me thinking that maybe it is the second thermostat or water control valve because my research says that the second thermostat controls cabin heat. From what I can see changing the second stat is harder than the first one...so if I don't have to...I don't wanna..lol (any tips or tricks for doing it?) Any other suggestions on what it may be? Any ideas as to why after clearing fault codes it stopped overheating (which I hate saying because from what I could hear, see and smell it wasn't)? Could it be a bad sensor? If so which ones? Any suggestions on what else I should replace if I have to change second stat, to avoid tearing into it in the future. Head Gasket appears good, no mixed fluids, no missing fluids, no funny noises, no funny smells I have a parts car...that ran great before timing chain jumped...this is where I got radiator n clutch fan Thanks for your help! |
#2
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The fact that start blowing hot air at higher speed, it tells me that you probably still have air in the system. We get the same problem at our shop all the time. It's very very difficult to get all the air out without a tool. My suggestion is to have a shop bleed the system for you with a tool, or buy/rent the tool.
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#3
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is it something I can rent from Auto Zone?
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#4
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I'm not sure, but if they do rent the tool, keep in mind that you also need compress air to connect to the tool.
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#5
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I always replace both thermostats (genuine Nissan parts), especially after an overheat. Yeah, it's a pain as there is not a lot of room back there! The coolant sensor is also back there. It does sound like there's air in the system, but I would replace the second thermostat and then try to purge the air. I use a Lisle Splii-free funnel attached to the radiator neck. I jack the front end of the vehicle up as much as safely possible. Add the coolant until it's about 1/3 up the funnel, start the engine, set the heater(s) to maximum heat. Run the engine at approximately 2500-3000 RPM for at least 10 minutes and the air pockets should make their way up and out through the coolant in the funnel. Eventually, the air bubbles should diminish and the heater should blow hot air. Once you have good heat, shut off the engine, lower the vehicle, remove the funnel and with the radiator full, install the cap. The reservoir should also be filled about halfway or to the MAX line. This works most of the time.
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#6
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FIXED!!
Sorry!! there was air and lots of it!! I drove it up on an incline, cut the bottom off a 2-liter and placed it upside down in my radiator then I taped the crap outta it. I filled up the fluid via the overfill. I started it and ran it for about a half an hour. It bubbled a lot and came up the 2-liter about half way. I recommend using a thicker plastic. After burping it, everything was great.
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heater, overheating, pathfinder |
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