FJ62 little heat from front heater - help needed (1 Viewer)

[Rigger]

Thanks for reading my thread.

Okay, here’s the deal: Recently replaced the radiator and many of the hoses. I also installed a new thermostat. A couple months after that, the water pump got really noisy. So I put in a new water pump. Everything seems to be functioning well; no leaks, no weird noises, etc. Runs great.

The weather here is getting cooler now, so I am starting to use the heater. The front heater seems to take a long time to deliver heat and even when it does, it is tepid, barely warm, not hot. Sometimes, though, it is a bit hotter. It is inconsistent. But the rear heater seems to work fine; it delivers real heat, hotter than the front heater.

I have searched and one thing that did pop up was the issue of the thermostat O-ring. I did take care to install the new t-stat correctly, so I doubt that this is the issue. It seems as though if I had a problem here, it would affect both heaters, not just the front one. However, I will pull that back out if I think that it could be an issue.

I am thinking plugged heater core. Or perhaps the valve that lets coolant into the front heater core is bad? It seems to work; I see the lever move and the plunger goes up and down. Any other suggestions? What do you all think?

As always, thanks in advance for your help.

 

[theRash]

The rear heater is virtually independant of the front heater. It can have heat while your front heater doesn't and vice versa. Definately not your thermostat either. I think you're on the right path. I'd start with flushing your heater core first. Sediments over time get deposited in it. clogging it. I seem to recall a few threads on how to do it and what to use. I'm sure others with actual experience doing this will chime in.

 

[RockDoc]

How is the airflow with the heater on? If its fine, then it must be water flow. Did it put out good heat before the repairs? If yes I would wonder about an air-lock (try running the truck up a steep hill at high rpm to force out any air?), if no, a flush is likely a good idea.

After my last coolant flush, it took a few days to get all the air out of the front heater and good heat back.

 

[Ming89FJ62]

Did you burp the coolant system? Do a search for FJ62 and burping. It's very common for air to get trapped in the 62 coolant system and when it does no heat. Simple to do and costs nothing.

 

[Rigger]

I searched burp and all I can find is suggestions that the front of the truck be elevated and then the engine run for a while. Will this suffice to burp the cooling system?

 

[theRash]

I searched burp and all I can find is suggestions that the front of the truck be elevated and then the engine run for a while. Will this suffice to burp the cooling system?

Do that above and also run your heater and keep the radiator cap OFF. While your car is running, front elevated, heater on, cap off you can watch the bubbles come up and your coolant level drop. Add coolant as necesary.

When I did mine this way I added almost another full bottle of coolant.

 

[ntsqd]

From looking at my 60 it appears that, for what ever reason, Toyota plumbed it that same as my 22-RTE truck. The heater control valve is the highest point of the coolant system. I have taken to loosening the hose clamp on the upper hose at the valve and bleeding out the air from there. Unfortunately since turbo twuk has a blown HG I get to do this ever time the heater quits working. Someday fixing him will be at the top of the priority list......

 

[cruiser_guy]

I've had the no heat from the heater problem and all it took was reverse flushing the front heater and valve. Try that and then run the truck with the front and rear heat on and park nose high for a few times (park at the end of the day and then top up coolant the next morning). Repeat until the cooling system remains full.

 

[Butt Ugly Chuck]

The Redneck burp setup is my never-fail method of getting the air out.

Butt

 

[Rigger]

I replaced all the remaining heater hoses and I flushed out the heater core. I used the vinegar method. I put in white vinegar and let it sit overnight, then flushed it out with warm water both directions. The flow of fluid thru the core seems to be good.

I still have tepid heat from the front heater. Dang!

I need to work more on this burping thing.

If I put the front wheels up on ramps, say 6" high, is that enough elevation for burping?

 

[PPFJ60]

Check the air diverter to make sure it is adjusted correctly. This is the temperature control lever that runs a gate in the heater box. It adjusts the amount of air that is forced to pass through the heater core or gets by passed and flows on through. Mine as miss-adjusted so that when the lever was on the highest setting the gate was not diverting all the air through the heater core.

 

[Rigger]

Thanks for the air diverter tip. I will for sure take a look at that. I keep hoping that the issue is a simple forehead slap type of thing!

 

[Rigger]

MY BURP ATTEMPT:

I put the passenger side front corner of the truck up as high as I could get it with my floor jack and a tall stand. I ran the truck for about 30 minutes with the radiator cap off. During this time, I lost about a pint, maybe slightly more, of coolant that overflowed out. I was not able to add any coolant.

In summary, I went backwards!

Please critique my method.

I also checked the air diverter and it seems to be functioning okay.

Edit:

After I finished, I drove it up some steep hills. Later, in the garage after cool-down, I popped the cap. the coolant level is right there, in the filler neck. Go figure!

 

[RockDoc]

My burp method (open to critique by others)- get the truck good and warm, a fair bit of coolant in the overflow, then run it up a steep hill in a low gear (to get the revs and water pump action at a maximum), opening and closing the heater valves as you go. If nothing else, it make me smile.

BTW, have you verified that the heater valve is working?

 

[Elbert]

Ok... make sure your heater control valve is working....the part at the firewall that controls coolant flow throught the heater core. Turn heat all the way to max hot. Run truck until it reaches operating temp. Are both heater hoses at the heater control valve hot to the touch? It takes some time to remove the air from the coolant system, as described you need to have the front of the truck higher than the rear.
Make sure the heater control valve works first just to physically confirm its not the problem.

 

[Rigger]

Thanks Rockdoc, Elbert:

When I replaced hoses this past weekend, I removed the heater valve from the firewall, inspected it, and confirmed that it operates correctly. It had virtually no gunk or build-up of crud in it, but I cleaned it with vinegar anyway. I have ruled it out as a problem.

I'm going to do some more of the steep uphill stuff and see if that helps.

I also have been wondering if I have a bad t-stat. But it seems to me that if I did have a bad t-stat, the rear heater would not work either.

I appreciate your responses.

 

[ntsqd]

Hum.... I've a 22-RET with a blown HG (name one that doesn't, but I digress). My burp method is simple and born of repeated need to do it until I can pull that vehicle down & fix it. I wait until I have run the engine long enough to have pressure in the system, then I slowly loosen the hose clamp of the highest hose which happens to be the supply to the heater control valve. Once I start getting consistent liquid dripping out I tighten the clamp. Ta-Da! Not so instant power bleed.
HTH

 

[Rigger]

Hum.... I've a 22-RET with a blown HG (name one that doesn't, but I digress). My burp method is simple and born of repeated need to do it until I can pull that vehicle down & fix it. I wait until I have run the engine long enough to have pressure in the system, then I slowly loosen the hose clamp of the highest hose which happens to be the supply to the heater control valve. Once I start getting consistent liquid dripping out I tighten the clamp. Ta-Da! Not so instant power bleed.
HTH

Thanks for this suggestion. I will give it a try. To clarify, should I have the truck running while I loosen that clamp?

 

[Rigger]

The Redneck burp setup is my never-fail method of getting the air out.

Butt

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?

I am considering trying this, in conjunction with the method in the previous post. I like the idea of creating a liquid pressure head with the funnel, then bleeding off at the firewall valve. That seems to me to make sense.

I'll let you all know what happens.

 

[ntsqd]

Thanks for this suggestion. I will give it a try. To clarify, should I have the truck running while I loosen that clamp?

I do it while running.