FJ62 little heat from front heater - help needed

[Rigger]

I do it while running.

Okay. I drove the truck home at noon, a distance of three miles, which I felt was ample warmup time. Then, with the truck hot and idling, I loosened the clamp at the heater valve. A few turns of the screw on that clamp and piping hot coolant came squirting out. No air, just hot coolant. I quickly tightened that dude back down!

Does this mean that the air is all bled out of that section of the cooling system?

 

[Cruiserdrew]

My take on the burping thing is that it's crap. There is no burping. It's the radiator cap in good working order that lets the system purge itself of air.

Here is what you should do. When filling the first time with a new rad or lower hose change it does help to fill the system with the front end raised. Fill the radiator, turn on the truck and open all the heater valves WIDE OPEN. As it starts to circulate the coolant, the level will drop an inch or two. Add more coolant. When the coolant starts to warm and expand, and the level rises, put on the radiator cap. Fill the overflow.

Now, when the truck starts and warms it will push the air in the upper part of the radiator into the overflow bottle where it will escape. As the truck cools on shut down, it will suck in coolant to replace the air. The first few warm cool cycles will purge ALL the air from the system. Just keep the overflow full. It also helps to open the heater at first start up. This increases flow in the head and will help to move any tiny bubbles of trapped air into the radiator upper tank where it gets purged as the car heats up.

Don't waste any effort on "burping", it doesn't make any difference. A working radiator cap, though, makes a huge difference, so get a new one.

 

[ntsqd]

The cap can not remove any air that is trapped above it. It is the inverse of a plumbing P-Trap. This is why the cap is supposed to be the highest point in the system. I don't understand why 3 of my 4 Toyotas aren't built this way, but they are not. (The fourth, a first gen MR2, is even stranger and has unique purging instructions.) Every other vehicle that I've ever owned, without fail, has the cap at the highest point of the system. The one race car that I worked on that did not, a IMSA Showroom Stock Mazda MX6, had us installing a -3 adapter and cap so we could easily purge it.

Wasn't the cap recently replaced? Not a guarantee of a good one, but the odds are against it being bad.

 

[RockDoc]

You've verified that the heater valve is moving with the slider in the heater controls? Isn't there a flap door that diverts air through or around the heater core too?

 

[Rigger]

Wasn't the cap recently replaced? Not a guarantee of a good one, but the odds are against it being bad.

No. The cap was never replaced. Funny; it never occurred to me to replace it. But, it sounds as though could potentially be the problem or at least part of the problem. I will replace it straight away.

I really appreciate you taking the time to share your thoughts.

 

[Rigger]

You've verified that the heater valve is moving with the slider in the heater controls? Isn't there a flap door that diverts air through or around the heater core too?

Thanks for posting.

Under the hood: When I work the slide, the heater valve opens. I do know that.

In the cab: When I work the slide, a lever on the duct box moves. I do know that. But, I can't confirm precisely what the damper is doing without tearing the duct open and looking. I have not done that yet.

 

[Rigger]

My take on the burping thing is that it's crap. There is no burping. It's the radiator cap in good working order that lets the system purge itself of air.

Here is what you should do. When filling the first time with a new rad or lower hose change it does help to fill the system with the front end raised. Fill the radiator, turn on the truck and open all the heater valves WIDE OPEN. As it starts to circulate the coolant, the level will drop an inch or two. Add more coolant. When the coolant starts to warm and expand, and the level rises, put on the radiator cap. Fill the overflow.

Now, when the truck starts and warms it will push the air in the upper part of the radiator into the overflow bottle where it will escape. As the truck cools on shut down, it will suck in coolant to replace the air. The first few warm cool cycles will purge ALL the air from the system. Just keep the overflow full. It also helps to open the heater at first start up. This increases flow in the head and will help to move any tiny bubbles of trapped air into the radiator upper tank where it gets purged as the car heats up.

Don't waste any effort on "burping", it doesn't make any difference. A working radiator cap, though, makes a huge difference, so get a new one.

Thanks, Drew.

One thing I am now doing that I did not do earlier is keeping the overflow bottle full. Maybe with a few more heatups and cooldowns, the problem will start to resolve itself.

I am assuming that I should go with a factory Toyota radiator cap. Is that a recommend, or will a Napa cap be just as good?

 

[Butt Ugly Chuck]

Chuck, thanks for this idea. I wanna make sure I do this correctly: To use your method, I create this funnel seal at the radiator cap, fill the funnel with coolant, then run the truck until hot. Is that correct?

Correctamundo. Def keep some coolant in the overflow though as Cruiserdrew recomends. Even after you think you've got it all burped, more will come out on subsequent drives.

Good luck!
Charlie

 

[ntsqd]

A random thought; can leaves etc. get clear into the heater core?
Could it be partially plugged with junk on the air (as opposed to coolant) side? I've read that its JOB to get in there, so I'm hoping this isn't too feasible of an explanation.

 

[Rigger]

A random thought; can leaves etc. get clear into the heater core?
Could it be partially plugged with junk on the air (as opposed to coolant) side? I've read that its JOB to get in there, so I'm hoping this isn't too feasible of an explanation.

Thanks for the suggestion. I am checking everything, so I will check this, too.

 

[sdbrassfield]

You say the rear heater "seems" to deliver heat, hotter than the front? That leads me to believe it is not really blowing the heat it should be.

O-RING

If your o-ring was not new when replacing the thermostat, replace it now. It is a slotted thermostat and a good bit of water will bypass the thermostat and it wiill take forever to warm up in the winter if it even warms up at all.

If that 3fe is not hot and up to operating temp by the time you drive 2-3 miles even in frigid weather, that 0-ring (or less likely the thermostat) is your culprit. Always replace the o-ring with the thermostat as the old ones tend to flatten out and not seal over time. I have seen it too many times...

 

[Dynosoar]

Try a beenie,warm jacket and some gloves. Then you will hardly notice how cold it is in Montana. As an alternative you could move to Southern California, then you will only need your heater 1 or 2 times a year. As a final alternative find an old VW gas heater. They run off of the fuel system and make tons of heat instantly no warm up needed.

You really need to pull the HVAC housing and pull out all the debris (leaves, candy wrappers, rat fur and droppings, etc.)packed around the heater core and while its apart you may as well put in a new one.


Dynosoar

 

[Rigger]

You say the rear heater "seems" to deliver heat, hotter than the front? That leads me to believe it is not really blowing the heat it should be.

O-RING

If your o-ring was not new when replacing the thermostat, replace it now. It is a slotted thermostat and a good bit of water will bypass the thermostat and it wiill take forever to warm up in the winter if it even warms up at all.

If that 3fe is not hot and up to operating temp by the time you drive 2-3 miles even in frigid weather, that 0-ring (or less likely the thermostat) is your culprit. Always replace the o-ring with the thermostat as the old ones tend to flatten out and not seal over time. I have seen it too many times...

Lemme clarify on the two different temperatures. My wording was not clear. The rear heater heats up faster and hotter. I have not used a thermometer to check the temps of the output air, but that rear heat air flow is hot, and the front heat air flow is cool to tepid.

The truck has a new t-stat, and the gasket and o-ring were put in new at the same time. These were new Toyota parts straight from Cruiser Dan the parts man. Here's the rub: when I installed the t-stat, I ruined the new gasket. I had to pull it back apart and install another new gasket, which I obtained locally from Napa. I could have damaged that o-ring then, on the reinstall. I am going to install a new t-stat, o-ring, and gasket now.

Thanks for the advice.

 

[Rigger]

Try a beenie,warm jacket and some gloves. Then you will hardly notice how cold it is in Montana. As an alternative you could move to Southern California, then you will only need your heater 1 or 2 times a year. As a final alternative find an old VW gas heater. They run off of the fuel system and make tons of heat instantly no warm up needed.

You really need to pull the HVAC housing and pull out all the debris (leaves, candy wrappers, rat fur and droppings, etc.)packed around the heater core and while its apart you may as well put in a new one.


Dynosoar

I have myself on Woody's '40 beenie list, but it is not here yet.

 

[MrMoMo]

I recently had my wiper motor out and found that the air INTAKE was severely blocked with all kinds of CRAP. I would suggest removing the wiper motor, and seeing how blocked your air intake is. How much air flow do you have? You might be getting all the coolant in the world to the heater core, but if you don't have crap for air flow, it won't deliver much heat.... Someone else on here posted about replacing the brushes in the blower motor, which gave them a lot more air flow - I have not done that, but if airflow is your problem... maybe that would help too... (just thoughts)

 

[Rigger]

I recently had my wiper motor out and found that the air INTAKE was severely blocked with all kinds of CRAP. I would suggest removing the wiper motor, and seeing how blocked your air intake is. How much air flow do you have? You might be getting all the coolant in the world to the heater core, but if you don't have crap for air flow, it won't deliver much heat.... Someone else on here posted about replacing the brushes in the blower motor, which gave them a lot more air flow - I have not done that, but if airflow is your problem... maybe that would help too... (just thoughts)

I will have a look at this, MoMo. Thank you kindly for your ideas and suggestions.

 

[Elbert]

what about my question.... are both heater hoses at the heater core hot when truck is fully warmed up?

You the correct thermostat and "o" ring installed?, you have no air in the coolant system? Your heater control valve works?...your temp door under the dash works for hot air.. , your truck is full of coolant , and you have no other heater or cooling issues. If all this is true then my money is on (1) you need a new heater core (2) your heater core is restircted.

 

[Rigger]

what about my question.... are both heater hoses at the heater core hot when truck is fully warmed up?

You the correct thermostat and "o" ring installed?, you have no air in the coolant system? Your heater control valve works?...your temp door under the dash works for hot air.. , your truck is full of coolant , and you have no other heater or cooling issues. If all this is true then my money is on (1) you need a new heater core (2) your heater core is restircted.

Sorry, Elbert, for not responding directly to your suggestions. I have been sort of sidelined a bit, and have not been focused on this matter. Thanks for posting.

I am going to check the hoses so that I can consider your first question.

I am not 100% certain that the t-stat o-ring is installed correctly. I have a new t-stat and o-ring and at some point, I will pull and replace both.

I am pretty sure the air is purged, and I know the valve works. The system is full of coolant as far as I can tell.

I have not yet confirmed that the duct door works.

I had a suggestion from another mudder that I try the front heater with the rear heater shut off. I did. The front heater works better if the back heater is turned off! This same mudder also suggested I use a 195 t-stat not a 180. So far, I have been unable to determine what temperature t-stat I currently have in the truck.

I am considering core replacement as a last resort because it is such a danged big job to replace it!

Does anyone think it could be the fan clutch? I don't think that has been suggested yet. Could that be the problem?

Thanks again, Elbert. I am continuing to plug away at this problem, and I appreciate your suggestions.

 

[CruisinMT]

if it were the fan clutch you would see a rise in temp as you sit idleing. MY bro had a heep (What a POS) that had the clutch fan going and everytime we stopped in traffic he would have to increase RPMs to keep it from overheating
.

 

[Zack1978]

Well I still have the exact same issues that you have. The heat out of the rear heater is so hot that it will almost burn your hands, and the main heat is just luke warm. I have taken every step mentioned in this thread, except the flushing of the heater core. I think that is where the issue must be. There was a Mark W thread of heater core fulshing that I have to find.


Zack