PDA

View Full Version : heater problem 74 fj40


Skip
03-06-2011, 10:35 PM
i could not find a post on this all though Iam a new guy to the site
I have a 74 fj40 350
My heater blows warm air-- bottom vent
cold air middle vent Lots
no air defrost position
I checked the heat valve and sprayed with pb blaster seems to b working inside hoses are warm
I need fan gaskets by the cowl dont think this is the prob not sure
any help would b appreciated
fan seems to only operate at high speed 2nd position
my rear heater is not installed

Thanks
Skip

RicardoJM
03-07-2011, 08:38 AM
i could not find a post on this all though Iam a new guy to the site
I have a 74 fj40 350
My heater blows warm air-- bottom vent
cold air middle vent Lots
no air defrost position

Welcome, you will find a bunch of great information and people on the site and in the Club.:D

This link (http://rzeppa.org/tech/staywarm.htm) has some very good information about keeping your cruiser warm in the winter. I understand you have a V8, so the thermostat gasket information may not be spot on - but the bit about the heater core being dirty might just apply.

I'm not familiar with the heater controls on a 74. On my 71, I have a flap on the heater. When I move the flap up, the air is directed to the windshield (defrost) via hoses on each side of the heater core. Do you have the hoses on the each side of the heater?

I checked the heat valve and sprayed with pb blaster seems to b working inside hoses are warm
I need fan gaskets by the cowl dont think this is the prob not sure
any help would b appreciated
fan seems to only operate at high speed 2nd position
my rear heater is not installed

Thanks
Skip
You indicate the hoses are warm, so it appears coolant is getting to the heater core. You will want to get a tight seal for the heater fan to the firewall and for the box/tunnel to the heater box. If there are any cracks/gaps it really makes the heater less efficient. The heater fan only operating on high speed is a common issue. There is a resistor on the fan and if it goes bad then you only have one speed. This post (http://forum.ih8mud.com/40-55-series-tech/98247-blower-motor-resistor.html) on Mud has some excellent information on making the repair.

MDH33
03-07-2011, 08:53 AM
Welcome to the RS forum.

In addition to what Ricardo said, make sure that the pull knob on the dash for fresh air isn't open. that opens the cowl vent and will blast cold air into the cab through the center vents.

Skip
03-07-2011, 10:36 AM
Thanks
I will check those things and update.
Does the gasket repair kit from SOR come with detailed instructions?
Also unrelated do you have a swap meet comming up in the Denver area soon.
Skip

Skip
03-07-2011, 10:42 AM
Ricardo
Yes I have hoses running up each side

Going to blow them out and vacume looking for possible squaters.

Had some chipmonks a few years back not by the heater though

MDH33
03-07-2011, 10:57 AM
Thanks
I will check those things and update.
Does the gasket repair kit from SOR come with detailed instructions?
Also unrelated do you have a swap meet comming up in the Denver area soon.
Skip


We have a Rally and swap meet at the Jeffco grounds in August yearly. :thumb:

Air Randy
03-07-2011, 11:03 AM
Contact:

Shane R. Walters
Metric TLc
Oregon City, OR 97045
aatlas1x@aol.com
503-740-2811

to get the heater box rebuild kits. Much less expensive that the SOR kits. He has complete step-by-step instructions too.

If you're getting good heat out of the bottom vent then your control valve and thermostat are fine. The middle position is a fresh air vent and is supposed to blow cold air. The top position is defrost. If your air hoses are hooked up and not cracked, but your not geting much air at the windshield, chances are that duct is plugged with a chipmunk nest and/or other other crud that has built up over 37 years. The factory foam seals will actually degrade and cause air restriction issues too.

Cheeseman
03-07-2011, 12:01 PM
Well Skip that didn't take long. I am the one who you spoke with up in Aspen Park Saturday. Very glad to see you aboard. Told you you could get some answers. And well....now you see. By the way, how was the pizza.

Skip
03-08-2011, 09:34 AM
Tore into the fan box yesterday
resealed at firewall old stuff gone(1/2" Camper tape all I had for now)Will check with metric (Good lead)to do it correctly.
Made sure side vent door was opperating correctly and sealing.
Im gathering the center vent should close off when in heat or defrost position??
Mine blows all the time reguardless of selector postion. (Pc of metal tape over it to keep from freezing)
Iam going to tear it down and rebuild should help me understand this puppy
Thanks for all the great support Greg was right in telling me to contact you guys.
PS Greg Pizzia was good looking foward to talking to you in the future

DanS
03-08-2011, 09:49 AM
Contact:

Shane R. Walters
Metric TLc
Oregon City, OR 97045
aatlas1x@aol.com
503-740-2811

to get the heater box rebuild kits. Much less expensive that the SOR kits. He has complete step-by-step instructions too.

This one. Shane is my hero. SOR is actually selling Shane's kits anyway, just with a markup.

Good luck getting it to heat. It's a pretty simple system, really, so I'm guessing that a simple rebuild kit and getting all the linkages moving again will fix your problem.

Dan

Skip
03-10-2011, 08:10 PM
update on my heater
removed blower vent box in the cab

alot of stuff on top of core blew it out and vacumed cleaned defrost hoses pretty clean before I started. Although not hooked up very well, reatached and taped in place.
Found a small door and a connectiong rod (I assume) laying down on top of core (Explains not being able to shut down that vent. I pushed it in place and taped closed for now till I can get the unit on the bench and rebuild gasket.
Reatched inside blower vent Camper tape again works pretty well at both ends
I now have defrost and better heat flow i even had to turn it off for a while while out this am thats a first for this trusty rusty
Thanks for all your help
I came across a third smaller hose behind the two attached to the core.
it is not attached to anything in the cab. ANy idea what it might have been or should b 4
I already have two hoses comming thru fire wall for rear heater