Hello all!
While working on the Pathy this summer, I accidentally pulled the coolant line out of the throttle body and leaked coolant everywhere. I just cleaned everythign out and re-installed it and thought nothing of it.
I recently turned on the heat and noticed that the heat blows cold at idle. Air in the system, prolly because of the stupid mistake earlier.
I am now trying to bleed the air out of the system, however, I cannot find the coolant vent location. I did some research and found a "Tee" on my coolant line to the heater through my firewall, however, it is blanked off and I do not see a plug that I can remove to install the poly tubing to burp the air out.
DOES ANYONE KNOW WHERE THE VENT IS LOCATED, OR AM I JUST BEING STUPID AND MISSING IT?
Secondly, I went to Nissan yesterday at 1:31 PM, and the parts office closed at 1:00 PM on Saturdays. FML. I really can't get there during the week.
Is it ok to just use the regular green coolant from the local auto parts store?
Thanks for the help!!!

I kind of doubt that it is an air pocket situation if it's something you did in the summer time, as you probably didn't loose enough coolant to create an air pocket with just disconnecting the throttle body hose and any air should have cycled it's way out by now. The R51's use a coolant system similar to many European vehicles, in that the radiator cap is not vented, rather the reservoir cap is. These systems are usually less prone to getting air bound. While there is a air bleed nipple with a rubber cap on it on 05-07 models, which is on the plastic coolant "tree" (for lack of a better word) on the passenger side of the engine compartment, near the firewall, where the heater hoses split-off to the rear heater, there is no such provision on 08-and-later models. The best way to purge the system is to make sure the radiator is full, install the radiator cap, fill the coolant reservoir to the "max" line, install the reservoir cap, park the vehicle on an incline with the nose uphill, start the engine and turn all heaters to the "maximum heat" setting and let it run. Other reasons for no heat could be low coolant level, stuck open thermostat, bad temp mode door actuator, wiring short/open, temp sensor (auto climate control) or control head. If the purge doesn't work, I would start by taking a look at the mode door actuator as they've been know to go bad. Unfortunately, some of the actuators need the dash removed in order to replace them and off the top of my head, I don't remember if that particular actuator is one of them. As far as the coolant, green or universal coolants will work fine. Around 2010, Nissan started putting longer-life, blue coolant in their vehicles.

Hey thanks for all the information!

I bought some Prestone concentrated mix and mixed it at 50% dilution.
Similiar to the other posts on here, I filled the radiatior, cut the top off a water bottle, and filled that wil coolant. I also filled the overflow to halfway. I put the cap on the overflow and left the bottle on the rad. Started the engine and let it idle. turned the heat to high. Bubbles started flowing out, and occasionally I would rev it up to about 2,000 rpm, which would bring out even more bubbles. I did this for about 20 minutes, and the system took about 6 cups of the mixture until I figured it was good enough to test.
Drove it this morning and heat was working at idle.

Maybe the rad was just low and all of the air would have purged ot of the overflow if I would have just filled that up, but it worked for me.

Thanks for the reply!

Make sure the reservoir cap is not installed if you run it with the radiator cap not installed, or you'll have a hell of a mess!

So I did it, and had a big mess. Lol. But then I cut the top off a bottle of water and did it again and it surged up about 4" and then just bubbled.

Yeah, that's what I figured. The only reason for the radiator cap on this system is so you can fill the radiator up after the system is drained. Then you're supposed to install it and purge through the reservoir. That's why there's no spring or vent on the radiator cap, like there is on the reservoir cap. On an R50 or WD21 Pathy, you would find the opposite.

I just did a coolant change last night for the first time at 98k. I bought the vehicle at 78k and I don't think the previous owner had ever done it. I drained about 1.5 gallons and filled the radiator and filled the reservoir to half way and replaced caps. Started it up and ran it for a while with the heat on, no heat.. so I pulled the hose clamp of of the heater return line coming out of the firewall and wiggled the line. Air came out followed by coolant. Still no heat. Then I turned on the rear vent to high heat in the cab and within a minute the heat was hotter than ever. I never burped the radiator or reservoir, just the heater return hose. No mess.

Yeah, it's important to set "all" of the heater controls to the maximum hot settings to allow the coolant to flow through the heater cores and push the air out of them. Some forget about the rear heater and that's a good place to trap air.

Well, I thought my method worked but I was wrong. Yesterday I got about a mile from my house and stopped at a gas station and the temp dropped to about a quarter way up the gauge and no heat. So I went home and got my other vehicle. Today I thought I would try to burp through the radiator so I jacked the front end up, opened the radiator cap and couldn't see fluid so I dumped half a gallon in and put a snug fitting funnel in the opening and started it. Immediately fluid surged out and filled the funnel and did not go back in. The vehicle got to operating temp and heat was on full but no heat. I turned off the key and started squeezing all of the heater hoses I could reach that were in that circuit. The fluid went back into the radiator. Then I topped it off and closed it. I restarted the vehicle and it had plenty of heat again. I am wondering if anyone knows the proper procedure for this job. Seems like a hassle doing it this way and worries me to potentially have an air pocket trapped in the engine. I am going to let it cool then take it for a drive and see if I have any more issues.

The correct way is to use a coolant system vacuum purge tool, which hooks up to an airline and puts the coolant system under a vacuum and then lets the vacuum pull the coolant into the cooling system. On vehicles with vented radiator caps, this is done at the radiator neck. On systems with vented caps on the reservoir, like our R51's, some GM's and many European vehicles, the tool mounts on the reservoir. One example of a such a kit is here:

http://www.matcotools.com/catalog/produ ... air-purge/

That would be very helpful. I believe I purged all the air out of it yesterday. I drove probably 70-80 miles, stopping different places with no loss of heat at idle. Thanks for the information.

I had the same problem and I solved my issue today. I just posted this in the "2006 Pathfinder thermostat replacement" thread. I think this is a good place to post it too.

It is that time of year again and we are all needing our heat. My heat has not blown warm at idle since I last changed my coolant and never blown warm in the rear at idle or at speed. There are schools of thought that suggest the thermostat is bad and yours may be. I replaced my thermostat today hoping to solve the problem. Took 45 min and my new thermostat was in. I have to say that when I removed the old one and it was in the closed position I knew I had replaced it for in vain.

If your heat blows cold at idle and then warm if you hodl the engine at 2000rpm or more, then your thermostat is NOT bad. You just need to bleed the coolant system. See below for link. I really had to hold the revs up to get the coolant to circulate. Do it right and you will have heat in the front and the rear. Glad this is done now. Bring on the cold weather. I'm happy to answer questions if I can be of help.



http://www.justanswer.com/nissan/63m0k- ... -idle.html

I am following the process in the link you posted paparomeo51. So I filled my funnel (the yellow one in the picture in the link) to a third full and pinched the two hoses. I have good heat in front and back after revving engine a while. But now the funnel is over half full which suggests I took coolant out of the system. Is this because the coolant is hot. The technician in that link doesn't describe how to finish the procedure as in button it up without introducing more air in. Any thoughts?

Hello Matt,

I didn't have a funnel to use when I did mine, so the coolant just blew out with the air from the radiator. I did have to add coolant after the engine cooled down so check your level. The coolant in your funnel is just lost when you remove it. No tthe best design I guess.

Papa,
Why would the coolant in my funnel be lost when I remove it? The funnel has a plug and makes it very nice for not creating spills. It makes it so you can pour the leftover coolant back into whatever container you want. My concern was that there was more coolant in the funnel than when I started meaning that I removed coolant from system when I was trying to put more in and take air out. I think the issue was my vise-grip on the hose going from the heater lines to the Reservoir was not tight enough so it was pulling coolant from there. I highly recommend the yellow no-spill funnel. keeps coolant from gushing out all over your engine and floor. I now have heat in the rear but it is not as hot as the front. I'm thinking maybe I did not get the front of the vehicle high enough to get the air out of the rear system.