Poor Heating '96 FJ80

[gr84mud]

Newer FJ80 owner ... our first Winter in the Northeast and we're finding that heating is a bit lacking. The FJ's motor/coolant appears to heat up at a respectable rate, but the cabin heating controls at max really don't pump out much hot air. The best we get is after maybe 15-20 minutes with it set to recirculated air and the rear blower on high. Forget about fresh air, the heater starts to blow mildly warm, almost cool air at best. I have reasonably good mechanical skills. If someone can point me in the right direction on what to check it would be greatly appreciated.

Thanks!

Brian
"Gr84Mud"

 

[CJF]

Where's your coolant temp. gauge sitting once the vehicle's warmed up?

Curtis

 

[gr84mud]

Guage

If memory serves me correct, about 60-65%/ a bit more than half way up.

 

[lndcruz]

Check the heater valve on the firewall. There is a mechanism that moves the valve from flowing to not flowing. It probably just needs to be adjusted

Check this thread to learn a little more about it.
https://forum.ih8mud.com/80-series-tech/173731-adjusting-water-valve-maximize-c-performance.html

 

[gr84mud]

(I'll censor my response slightly)

Friggin' awesome! That could be it. I'll check it out when the wife rolls in tonight (yes, it's "her car"). If I fix this problem It'll make the wife really happy, and I may get lucky as a result.

That's it. I'll let you know the outcome.

Brian
"Gr84Mud"

 

[gr84mud]

Heating Issue Solved.

Check the heater valve on the firewall. There is a mechanism that moves the valve from flowing to not flowing. It probably just needs to be adjusted

Problem solved. The valve was fine, but you pointed me in the right direction. I disconnected the control cable and manually opened it to full position just to be sure. Inside I set a thermometer at various points, starting with the dash, then under the rear seats ... I was getting well over 120 degrees so I was a bit puzzled. Then I went to check the front footwells ... no air. Crawled underneath and noticed on the passenger side that the carpeting was covering the vent ... okay, first problem. I pulled away the carpeting the find the next problem. The control arm to the footwell vents was disconnected, why I couldn't imagine. Reconnected the control arm, checked the vent selection buttons to send it all to the footwells and had a nice flow of heat.

While fixing the carpeting mess, I found a boatload of wires. Turns out they had an old mobile phone adapter and monster mobile antenna tucked under the passenger carpeting. Somewhere along the line they knocked that heater control arm off and blocked the vents.

So the wife will have heat now in the LC. I'm a happy guy.

If you're interested, here's the pics of event: Landcruiser Heating Issue

Brian
"Gr84Mud"

 

[lndcruz]

Good, glad I could help.

 

[Recovering40driver]

Thanks

This helped me fix my heat. The rear had been working great but the front was only luke warm at best. After looking at the water valve and playing with the temperature selection I discovered that when the PO had the hoses replaced before I bought it the hose clamp was limiting the travel of the cable. Now I have heat, which is a good thing with the negative temps in the morning.

 

[MrOffshore]

I think I might check into a few things on mine...I almost dread driving this truck in the winter...it just doesn't get warm and the rear defroster is basically useless...only melting a thin line at the wires...was thinking not many amps are flowing back there...not sure how to check to see if I have enough power hitting that line. But I seem to get some air movement, it just takes forever for it to warm up. I have a 2007 335xi BMW and it's toasty warm in just a few minutes...guess technology might be a bit better now, but I don't remember suffering in cars back in 1995 (the year of my TLC). I will take a look at some of the things mentioned here and see what I can find. Great images of the situation...thanks for posting and hope you got lucky!!

 

[greentruck]

Just to reassure any 80 drivers who aren't getting heat in these cold temps...

YES!

You should have all the heat you need -- and more!

In fact, if it's anywhere above 0 degrees F outside and you don't have to slack it back some after the first 10 minutes of fully warmed up driving -- you have some sort of problem. Find it and fix it. Your LC should provide all the heat you'll ever reasonably need, especially if you kick in the rear heater.

 

[Paltamo]

I did take off blower motor on my truck and used the vacuum cleaner to clean off the years of dust from evaporator "grill", that did help too. Especially blowing action(more blowing power).

 

[ralphy1997]

I think I might check into a few things on mine...I almost dread driving this truck in the winter...it just doesn't get warm and the rear defroster is basically useless...only melting a thin line at the wires...was thinking not many amps are flowing back there...not sure how to check to see if I have enough power hitting that line. But I seem to get some air movement, it just takes forever for it to warm up. I have a 2007 335xi BMW and it's toasty warm in just a few minutes...guess technology might be a bit better now, but I don't remember suffering in cars back in 1995 (the year of my TLC). I will take a look at some of the things mentioned here and see what I can find. Great images of the situation...thanks for posting and hope you got lucky!!

One thing to remember when having problem with heat is the thermostat. If it isn't working right, your vehicle won't maintain the correct temperature and your heat won't work right. If your temp gauge fluctuates that likely indicates a thermostat problem. If it's not fluctuating and holds steady even when going down a long hill, you may have an airflow or other mechanical issue in the hvac system and not a problem with the thermostat.

 

[lt1fire]

I need to find what the hell is wrong with mine. barely any hot air. I've just bypassed and taken out the water valve so it acts like it is on full all the time still nothing. flushed the system for a long time. Nothing.


Only question I have is mabe the door letting air run over the heater core isn't working and opening.

 

[greentruck]

Definitely check for the door to make sure it diverts air over the heater core.

Also, what about rear heat? You should be getting something there, even if the front heat is messed up, assuming you are getting circulation through the heat side of your cooling system.

Also, I'm not sure, but are the HVAC controls dependent on vacumm lines for switching? That could be one sources of problem with the diverter door, etc.

 

[lt1fire]

that is something i was wondering


If it gets warm enough to take a look this weekend I might pull the dash apart.

 

[96r50]

Just to reassure any 80 drivers who aren't getting heat in these cold temps...

YES!

You should have all the heat you need -- and more!

In fact, if it's anywhere above 0 degrees F outside and you don't have to slack it back some after the first 10 minutes of fully warmed up driving -- you have some sort of problem. Find it and fix it. Your LC should provide all the heat you'll ever reasonably need, especially if you kick in the rear heater.

Agreed! Once the truck is up to operating temps I have to keep the heat slider centered under the third fan speed button or I roast!

One thing to remember when having problem with heat is the thermostat. If it isn't working right, your vehicle won't maintain the correct temperature and your heat won't work right. If your temp gauge fluctuates that likely indicates a thermostat problem. If it's not fluctuating and holds steady even when going down a long hill, you may have an airflow or other mechanical issue in the hvac system and not a problem with the thermostat.

x2.

Definitely check for the door to make sure it diverts air over the heater core.

Also, what about rear heat? You should be getting something there, even if the front heat is messed up, assuming you are getting circulation through the heat side of your cooling system.

Also, I'm not sure, but are the HVAC controls dependent on vacumm lines for switching? That could be one sources of problem with the diverter door, etc.

x2 on the rear heat question. The coolant lines split and run in parallel to the front and rear heater cores. If you have tonnes of heat coming out of the rear heater chances are your front heater core/system is at fault.

The controls are electric and cable on these things; no vacuum lines.

 

[michel77]

Updates?

Was wondering if there were any updates on this. Think I read all the threads on heating issues over the weekend, most seem to trail off without revealing the fix..
My issues are similar. Started with cabin not getting cold enough, did some research and found the water valve cable was poorly adjusted and did not close the valve fully when on cold. Fixed that, drove around for a few weeks, actually had some nice weather up here in the NorthWest and didn't need the heating much.
Then over the past weekend we went camping at Rainier, freezing cold and humid, slide the temp control to full heat and....nothing Rear heat worked fine so used that and recirc to warm up the cabin.
Played around with it some more yesterday and got the heat going again. It seems the cable to the valve is not moving all the time (freed it up some with silicone spray), but then when I tested it with the valve fully open (i.e. heating position) and the cable disconnected I still didn't get any heat, so now my guess is that either the blend door is not working well or not moving freely or the air mix servomotor is about to go out (although, IIRC, these things either work or don't, no in between). Another option might be the front heater core being (partly) clogged, but I doubt that since I did get the heat going a couple of times and the PHH was replaced late last year with a full flush of the system (courtesy of PO).
Where is the blend door located exactly? I checked the FSM but find the drawings in there not always entirely clear.. I would really like to avoid taking down the whole dash if at all possible (especially since I live in a condo and do my wrenching on the street..).
Thanks guys!!

 

[gr84mud]

Was wondering if there were any updates on this. Think I read all the threads on heating issues over the weekend, most seem to trail off without revealing the fix..

In my case the fix was fixing the loose cable and tucking the carpet back where it was supposed to be. Now it runs real hot ... haven't had an issue since.

 

[lt1fire]

In my case the fix was fixing the loose cable and tucking the carpet back where it was supposed to be. Now it runs real hot ... haven't had an issue since.

Loose cable where??

 

[michel77]

In my case the fix was fixing the loose cable and tucking the carpet back where it was supposed to be. Now it runs real hot ... haven't had an issue since.

Thanks, was it the cable to the firewall heater valve or are you referring to the control arm for the footwell vents?

Loose cable where??

+1. I take it you haven't solved your issue yet?