Gents,

I know this has probably been beaten to death but want some new information on the subject.

Have a 09 Pathfinder. There is absolutely no heat at idle. Start it up in the morning to warm up, blowing cold air even after 20-30 mins. The minute you hit the gas and raise engine rpms, VIOLA! Here comes the heat. Also, when engine is up to operating temp, the temp gauge is between the middle and lower hash marks. I know that these cooling systems are prone to getting air in them but I was also thinking of changing the thermostat too. From what I read, the thermostat is located in the lower part of the motor where the lower rad hose comes off. Is this true?

My plan is to burp the system but I dont have that burp port that older model Pathfinders have located by the firewall. Guess I will do the old remove the rad cap process.

Checked for leaks. no leaks. Tranny fluid is cherry and shifts smooth. I bypassed the tranny cooling lines from the rad a while ago so...

Anything else that you guys would have me check?

Thanks,

Chris

Raise the front end and turn front and rear heaters (as applies) to maximum heat settings when you attempt to purge. Follow the lower radiator hose to the thermostat housing; the housing and thermostat are one unit and gasket is sold seperately. Nissan gaskets are layered metal whereas most of the aftermarket gaskets are paper. My Pathfinder (06) has three marks on the gauge, the lower two for the "normal" range and the top one to mark the "overheat" range. The needle should stay steady dead center between the marks of the "normal" range after it warms up. If it's down near the cold mark, then the thermostat is likely stuck open and should be replaced.

double check that your coolant level isn't low. i've had that happen in other cars. there was enough to keep the engine 'cool', but no heat out of the heater until you give it some gas. giving it gas spins the water pump faster thereby putting more pressure/flow into the system, which would then circulate the coolant through the system by force (including through the heater core) which would then give you heat. now this was told to me by a GM mechanic that taught me how to work on cars back when i was like 16, sooooo


while at idle (right after startup) put your hand on the upper radiator hose. you should be able to feel the coolant circulating. if you don't then that's a good indicator there's not enough in the system. and also squeeze that hose. if it's not real solid there's probably air in it.


i was taught to do the burp by starting out with it cold and leave the radiator cap off. then start the engine. keep squeezing and letting go of the upper hose and add water/coolant through where the cap goes. once the coolant reaches the top where the cap goes, replace the cap. keep squeezing the hose a few more times and then you're done. or at least that was the way i did it on my old '82 mustang and taurus when i first started driving.

Well, I think I may have successfully bled the system. I took both caps off and started the nissan. Turned heat of high and let it run for a little while. Antifreeze started coming out of rad so I capped that one leaving the.overflow cap off. Starting adding coolant and kept walking back to vents to feel air. Once both front and rear got.hot enough, I pored just a little more into the overflow bottle and put cap on. All in all, took me about 35 minutes. Was blowing real warm. Upper rad hose, heater core hoses, and bypass hoses were hot. Only hose that was cold was the lower rad hose. Not sure why that is. Also, the pressurized cap was on overflow bottle and not rad. That seems odd. Let me know ur thoughts gents.

Yes, the reservoir cap is actually the pressure cap. It is similar to the system European and some US cars have been using for years. The cap on the radiator tank is only there to assist in filling the system during servicing.

Does it make sense that the lower hose is cool to the touch? Was concerned about that so I drove it around for 15 mins with my scanner on it to monitor temp. Never went over 190.

Lower rad hose is the return from the rad, it should be 'cooled' coolant. Sounds like your radiator is doing its job!

Cool. Used to older cars where both hoses are warm. Well, wife got into pathfinder this am after it was running for about 15 mins. Said it was nice and toasty so i guess it worked. I will keep u guys posted with progress. Thanks so much for the help!

BTW, Does anyone have aftermarket exhaust on their pathfinder? Thinking about putting one on but cant find anyone who makes one.