Lack of heat volume in 93 XLT

[guy1968]

HI.

I bought my Explorer back in Sept. There was very little air flow but the air coming out the vents was reasonably hot. Shortly after the blower motor died so I replaced it with a NAPA unit. Now there is more air flow but not enough to heat the truck at the now -23C temps.

I changed the t-stat, flushed the system and now the air is HOT but, of course that did nothing to provide more flow. I made sure the blend door is working and there are no obstructions in the system. It is sealed properly where the motor is attached to the firewall.

The voltage at the blower is 13.8 under load and 14.5 with the motor disconnected and the fan switch on hi.

Does anyone have any ideas? Am I missing something obvious?

Any help is very much appreciated.

 

[RiverRat]

2 things I would check are for a plugged heater core. Try putting a hose up to one end of the core and see if water flows out the other end at a good rate.

Look at the heater core to make sure it isn't covered with junk like a rats nest, paper, or something keeping air from flowing through it.

 

[chasfish]

Don't know your progress, but you should check your heater control valve. I recently had lots of air, but no heat. Not quite your problem, but might be worth look.

Chuck

 

[i3uixp]

how do you fix TOO MUCH heat??

 

[guy1968]

Originally posted by RiverRat
2 things I would check are for a plugged heater core. Try putting a hose up to one end of the core and see if water flows out the other end at a good rate.

Look at the heater core to make sure it isn't covered with junk like a rats nest, paper, or something keeping air from flowing through it.

Thanks for the advice. I have torn apart the whole ducting system and found nothing that could impede air flow. The heater core is clear and the engine is reaching operating temperature.'

 

[wilkin250r]

I'm new to this forum, so bear with me if I make a rookie mistake.

The heater core should always have hot water flowing through it, and the selection between hot and cold air is a flap that either directs air through the heater core, or it doesn't. Either way, the heater core is always hot.

However, it doesn't sound like you are having problems with tempurature, but rather with airflow. If you had lots of airflow, but it never got hot, I would say you had a heater core problem.

All the suggestions so far have dealt with airflow, but no heat. Your problem seems to be the exact opposite. Lots of heat, no air flow. It still sounds like the problem is in your fan, or something impeding airflow.

Do you have decent airflow when using the air conditioner or just blowing cold air?

 

[Maniak]

Starting in late 1993 (some '93s have them) they added a piece called a heater control valve. Its job is to keep the hot water from going into the heater core. By keeping the water out, the AC will actually be cooler.

I went out a bought one for a 1994 X and hooked it up (When my a/c control is on max a/c it closes the valve). This dropped by a/c temp by almost 10F.

If you have a heater control valve it will be under the hood in the heater lines (its in the middle of both of them). Normally its near the firewall. if you heater hoses go from the motor to the firewall, with no valves in the middle then you don't have a heater control valve.

~Mark