no heat, only when driving. what gives?

[hkmaster]

hey everyone, i'm new to the path. well here goes, i have an 05 pathfinder that only gives out heat when i'm driving. On idle no heat just cold air plus when i do get heat i can't regulate it just very hot that's it. Also no heat in the rear. I did some research and came up with nothing. Any help would be greatly appreciated, before i take it to the stealership. thanks

[NVRDONE]

Have you checked the coolant level in the system ? No coolant = no heat.
If there is no coolant, where did it go.
Also check the thermostat. If it's stuck open, the engine does not come up to operating temp & you get no heat.

[myriad46]

There can be a couple of reasons for this. First, is the temp gauge in the dash coming up, or not? If it's not coming up, than there could be a problem with the thermostat as NVRDONE suggests.

If the gauge climbs as normal, but there is still cold air coming from the vents, until you get driving down the road, then HOT air comes out... You could have air bubbles in your radiator.

The quick procedure is this... (summarized from offical nissan procedure, search for that if you are uncertain about doing this).

- Wait till the engine is cold.
- Raise the front end of the truck with a jack or on ramps.
- Take the pressure cap off the radiator itself.
- You'll want a good wad of rags around the cap, and maybe some on the ground, because it's going to burble out some coolant.
- Let the truck come up to temperature a little.
- You may see some air bubbles come out and the level go down. That's good.
- Once up to temperature, or after a couple minutes, gently rev the engine a little. Nothing crazy; maybe 2000 rpm, a couple times, slowly. Too fast and your engine compartment's gonna get a bath.
- If the level is down at that point, add coolant to top off.
-----------------Careful, the coolant will now be HOT!-------------------------
- Close the cap and make sure the overflow resevoir is up to the "Hot" line. You're probably going to need to add some.
- Lower the truck and shut it off.

As the truck cools, it should suck out of the resevoir as needed. Once cooled, take a look at the resevoir and see if there is any in there. If there is some, but it's low, add up to the "cold" level and you should be good to go. (it might be called Min and Max, I can't remember right now) If it's gone entirely, let the car heat up, add again to the hot line and let it cool back down. This is something that you can do over a day or two, your truck will still work.

I had to do the process twice, but that was last winter and have not had a problem since.

Not sure if the no heat in the rear is related. If it's a separate radiator coil, it could be the same issue, but it's all connnected so this should fix it.

[bigmankz]

i had the same problem recently. the coolant disappeeared somewhere. no leaks in the engine. no leaks in plumbing, no coolant fumes from the exhaust but it it was gone. I added approx 1 liter of coolant and the problem of no heat on idele is gone. by the way where else the coolant went?

[disallow]

i had the same problem recently. the coolant disappeeared somewhere. no leaks in the engine. no leaks in plumbing, no coolant fumes from the exhaust but it it was gone. I added approx 1 liter of coolant and the problem of no heat on idele is gone. by the way where else the coolant went?

I had about 1 gal of coolant disappear in my 05. It was after heavy towing. I think it must have evaporated or something.

I refilled it, and its been fine ever since (almost 2 yrs and I have done heavy towing since).

I did have the truck checked for leaks at the stealer, they found nothin.

The way I detected it? No heat in the rear of the truck when it got cold out. After filling up, problem was solved.

t

[hkmaster]

Anyway thanks alot guys, the info was greatly appreciated. After writing this post i went out and check the coolant level and everything was fine the truck would get up to normal temp but still no heat. So i spoke to a few mechanic friends and went to a local shop. Turned out the coolant had to be flushed and repressurized. Works fine now, as for the no heat in the rear, i need to replace the blower motor. Might have to take it to dealership for this one unless someone knows how to change it. Thanks again.

[webmastir]

Anyway thanks alot guys, the info was greatly appreciated. After writing this post i went out and check the coolant level and everything was fine the truck would get up to normal temp but still no heat. So i spoke to a few mechanic friends and went to a local shop. Turned out the coolant had to be flushed and repressurized.

hrm. called a local dealership to ask how much to get coolant flushed/repressurized, they said 90$ (89.95). that an ok price for this you think? or is the process pretty simple to do on your own? don't know when the last time coolant was even changed in this thing. prob been a while i imagine

(110k miles on a 2006 se)

[disallow]

Anyway thanks alot guys, the info was greatly appreciated. After writing this post i went out and check the coolant level and everything was fine the truck would get up to normal temp but still no heat. So i spoke to a few mechanic friends and went to a local shop. Turned out the coolant had to be flushed and repressurized.

hrm. called a local dealership to ask how much to get coolant flushed/repressurized, they said 90$ (89.95). that an ok price for this you think? or is the process pretty simple to do on your own? don't know when the last time coolant was even changed in this thing. prob been a while i imagine

(110k miles on a 2006 se)

Thats a good price to have a shop do it. You would need at least 2, probably 3 jugs of premix to do it yourself. That and about an hour or so to drain and refill.

t

[gkb62001]

Not only that, but they'll pressurize it to make sure there are no bubbles. I've tried the burping method twice and am about to give in to just have it flushed and re-pressurized. Someone had posted about releasing air at a cap at some point in the lines and I'm willing to give that a shot if I can confirm where it's at.

[webmastir]

Cool. I just realized that seems way too flippin cheap for a dealership. I bet that douchebag didn't include labor in that. Tricky tricky..

[Kidd_Funkadelic]

I might also point out to check the fluid level in the radiator itself.

I had noticed a loss of heat at idle a few times and at first figured it could not be coolant level because the overflow jug was above the high mark at cold. But for whatever reason the radiator itself was actually low when I finally decided to check that too. I put in probably about 20oz of water and it came up to about full. Then a few days later I got some antifreeze and looked again and it took about another 15 give or take.

Haven't checked since but the heat seems better...

[webmastir]

Interesting. I checked it at cold, and the overflow jug seemed to be full. I checked the radiator, and it almost looked empty. I just assumed it was because the vehicle had been off for so long. Isn't the overflow jug supposed to compensate for lost(used) fluid in the main rad itself?

[disallow]

Interesting. I checked it at cold, and the overflow jug seemed to be full. I checked the radiator, and it almost looked empty. I just assumed it was because the vehicle had been off for so long. Isn't the overflow jug supposed to compensate for lost(used) fluid in the main rad itself?

The rad shouldn't drain when it sits. The overflow jug isn't overflowing, is it? That could be a sign of failed head gasket. Yuck. Probably not your problem though, I've never heard of bad head gaskets on the VQ40.

In any case, if the rad is empty, I would fill it up. If the rad seems empty, it could be indicative of air working its way to the highest point in the system, ie the system is 'burping' itself. Filling it up could solve your no heat issue, as long as the coolant isn't leaking out somewhere.

t

[driftedoffroad]

http://www.thenissanpath.com/viewtopic.php?t=4588

link to a similar post. there is a link in there with a good way to do it yourself.

[webmastir]

Thx


Future onlookers:

Here is a how to for clearing the air from the system. http://www.thenewx.org/forum/showthread.php?t=24370