Very poor heat

[crispins]

2006

I bought it this year.

it had Zero heat when I got it.

I have changed the thermostat

I have bleed it 2x (parked front up a hill, ran it at 2,500 RPM for 10 mins with the cap off the coolant reservoir

I have some heat, it is not hot at all.

I have the rear heat as well which gets the same level of 'warm' as the front does.

I am at a loss.

What should I do?

[smj999smj]

What kind of thermostat are you using...and do you know the part number?

[crispins]

What kind of thermostat are you using...and do you know the part number?

I used this one

212004W01B

[crispins]

I also forgot to mention that I also bled the system by putting a hose on the nipple on the heater hose junction on the passenger side and running the hose into the coolant reservoir while letting the truck run for a while.

[Thupertrooper]

Do you have rear heat\air?
make sure to run it also.

[crispins]

Do you have rear heat\air?
make sure to run it also.

I have rear heat and I am running it.

[smj999smj]

It sounds like you installed a Nissan 189 degree thermostat, which is good. The coolant temp gauge needle should sit almost dead center in the heat range on the gauge (if it's reading on the cold side of the range, you may have gotten a faulty thermostat). If that's the case, it's likely not an issue of the coolant not getting hot enough. When you do the purge procedure, install the cap on both the reservoir and the reservoir to allow the system to pressurize. Couple of things that could be the problem. The heater core could be clogged, which isn't a common issue on these vehicles. The air mix door that controls the flow of air through the heater core (in heat mode) or bypassing it (for cold air) may have an issue, such as a jammed mode door or a bad mode door actuator; both of those issues are a pain because the dashboard has to be removed to access the heating and cooling unit where those parts can be accessed. Another possibility is a bad "heater pump." The heater pump is a small, electric, water pump that mounts inline with the heater hose and helps push the flow of coolant through the heater core. It's mounted to a metal bracket that bolts to the firewall in the engine compartment and it's on the passenger side of the power brake booster and just above the left bank valve cover, so it's not hard to find. There will be two wires going to it and some people have mistaken for a "heater cock" or "valve." I think the heater valve would be the part I'd check next, maybe even just try tapping on it a few times with a small wrench in case it's stuck and see if the heat temperature gets hotter.

[crispins]

Well heck.

I sure hope that is not the case.

My temp needle does not go to the middle, it hangs pretty low.

I found changing that thermostat to be quite a PITA, took me way longer than I thought it should.

My next step will be to use my IR thermometer and get some temp readings around the engine compartment. I will also check to see if that booster pump is working correctly.

Thank you for all the good information.

It sounds like you installed a Nissan 189 degree thermostat, which is good. The coolant temp gauge needle should sit almost dead center in the heat range on the gauge (if it's reading on the cold side of the range, you may have gotten a faulty thermostat). If that's the case, it's likely not an issue of the coolant not getting hot enough. When you do the purge procedure, install the cap on both the reservoir and the reservoir to allow the system to pressurize. Couple of things that could be the problem. The heater core could be clogged, which isn't a common issue on these vehicles. The air mix door that controls the flow of air through the heater core (in heat mode) or bypassing it (for cold air) may have an issue, such as a jammed mode door or a bad mode door actuator; both of those issues are a pain because the dashboard has to be removed to access the heating and cooling unit where those parts can be accessed. Another possibility is a bad "heater pump." The heater pump is a small, electric, water pump that mounts inline with the heater hose and helps push the flow of coolant through the heater core. It's mounted to a metal bracket that bolts to the firewall in the engine compartment and it's on the passenger side of the power brake booster and just above the left bank valve cover, so it's not hard to find. There will be two wires going to it and some people have mistaken for a "heater cock" or "valve." I think the heater valve would be the part I'd check next, maybe even just try tapping on it a few times with a small wrench in case it's stuck and see if the heat temperature gets hotter.

[stmcelroy]

Does the A/C work?

I'd bet it's a blend door actuator.

I'm having issues with no heat or A/C on the drivers side and that's what is wrong with mine.

[crispins]

Does the A/C work?

I'd bet it's a blend door actuator.

I'm having issues with no heat or A/C on the drivers side and that's what is wrong with mine.

Yes the A/C works great, no issues.

[crispins]

I made some progress today.

I ran a hose from the Nipple on the split to the rear heater core and let that run into the reservoir for a while while revving the engine.

I then capped it off and then started slowly adding coolant onto the rexivor.

it would bubble a little every so often then the level would drop down like 1/3 inch and I would add more coolant. I did this for around 1/2 hour.

I also squeezed the upper radiator hose a bunch during this process.

I now have the heat the hottest it has been so far.

I do not think it is as hot as it could be but it is def rather hot now.

I think I still have some air in the system and will continue the process a few more times.

What a PITA.

I have taken it from no heat at all to a pretty good level of heat.

I also verified that the booster pump is getting power.

[palmerwmd]

Good job!!

[smj999smj]

Just because the heater pump is getting power, doesn't necessarily mean it's working. However, I am more suspect of a faulty thermostat since you claim the need is near the low end of the gauge. It sounds like it's partially stuck open.

[Thupertrooper]

I have always had the problem of no heat when idling from start up. My thermostat Im guessing works to well and my truck will not warm up enough to have heat just from idling. I have to actually drive it around.

[But I LOVE him Jerry]

I had this issue & went the clogged route. With some excellent instructions gleaned from the folks here, I drained the coolant, flushed well, which caused it to barf the automotive equivalent of a snotty hairball, flushed some mo' & mo', refilled with coolant, burped it well and voila!! I had GOOD heat!! Sometimes the magic works!!