The Nissan Path

Over the past 2 weeks I've become more worried over my 08 pathfinder. First alarm to go off was a sudden massive drop in fuel economy with no driving changes and same fuel. From 350 miles per tank to barely 300. That got me to checking more. The rear heater is sporatic sometimes no heat at all when I have heat up front. The temp gauge seems maybe a tad on the cool side but I may be wrong. It's definately below the halfway point by a little. Also when we talking about coolant I am worried about it mixing in the transmission so when I check the tranny dipstick its a very clear with a hint of brown in it. Any help or suggestions are greatly appreciated.

Sometimes I think we get accustomed to summer weather and summer fuel. Some of the fuel issues you mention may be the result of winter blend and cooler temperatures (means longer warm-up time/runs rich longer). Per my ScanGauge2 readings on a usual short route, mileage is 10% worse the past couple of weeks. Keep in mind that grease/fluids are thicker in cooler temps. Also tires may not want to flex so easily. One trucker long ago reminded me that even the cold air is denser.

I understand some slight mpg loss during winter but this is a sudden loss of like 20% It makes no sense. I would like to believe it could be a stuck open thermostat.... also what about the slight brown hint of color in the tranny fluid?

have you bypassed your transmission / radiator ?

dawgn86 wrote:have you bypassed your transmission / radiator ?

. Negative

I'd do a drain asap and check the fluid

My rear AC quit working this summer and the heat isn't working this winter. I'm also getting no heat at idle from the front sporadically. I've always had problems with the heat/ac from day 1 so I'm not sure if it's just the extension of that problem getting worse or something else. There are times in the summer you have to set the temp to 80 to keep it from freezing you out...and other times you have to set the heat to 65 to keep it from boiling you. Then other times (typically when it's very cold) it doesn't put out enough heat even if it's set to 80. Seems like it's one of the temp sensors but I'm wondering if this no heat at idle thing isn't something else.

can you take your radiator caps off and check for any oil residue on top? you would usually see the oil in the radiator easier than on the tranny stick

Radiator cap looks good. Can anyone tell me if the mostly clear tranny fluid with slight hint of brown is normal?

dervin29 wrote:Radiator cap looks good. Can anyone tell me if the mostly clear tranny fluid with slight hint of brown is normal?

its normal. if you see strawberry milkshake oil in water emulsion then theres a problem

skinny2 wrote:My rear AC quit working this summer and the heat isn't working this winter. I'm also getting no heat at idle from the front sporadically. I've always had problems with the heat/ac from day 1 so I'm not sure if it's just the extension of that problem getting worse or something else. There are times in the summer you have to set the temp to 80 to keep it from freezing you out...and other times you have to set the heat to 65 to keep it from boiling you. Then other times (typically when it's very cold) it doesn't put out enough heat even if it's set to 80. Seems like it's one of the temp sensors but I'm wondering if this no heat at idle thing isn't something else.

Have you tried replacing the thermostat?

smj999smj wrote:

skinny2 wrote:My rear AC quit working this summer and the heat isn't working this winter. I'm also getting no heat at idle from the front sporadically. I've always had problems with the heat/ac from day 1 so I'm not sure if it's just the extension of that problem getting worse or something else. There are times in the summer you have to set the temp to 80 to keep it from freezing you out...and other times you have to set the heat to 65 to keep it from boiling you. Then other times (typically when it's very cold) it doesn't put out enough heat even if it's set to 80. Seems like it's one of the temp sensors but I'm wondering if this no heat at idle thing isn't something else.

Have you tried replacing the thermostat?

No. Engine temps seem to be right on the money and it's so erratic it really seems like it has to be the hvac controller or some sensor attached. I've found that there are two sensors..one inside the car and one outside. They're only about $50 a piece but I just haven't messed with it. I'm assuming the rear heat/ac has some blockage or something in the lines. No leaks anywhere.