heater working but not well - Ranger-Forums - The Ultimate Ford Ranger Resource

General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

LinkBack Thread Tools Search this Thread
Old 12-02-2014
Thread Starter
Join Date: Dec 2014
Location: petrolia
Posts: 1
heater working but not well

hi new to this site and am hoping for info about the heater in a 2008 ranger.
My blower works but the heat that is put out is probably only half of the strength I should be getting
Does anybody knows what I need to do to fix this problem?
Note when i change from air conditioning which does work to heat I can hear the changing of compartments )
Reply With Quote
Old 12-02-2014
RF Veteran
iTrader: (1)
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,577
I assume temp gauge on dash is reading warmed up the same as usual, if not thermostat on engine is stuck open so engine can't warm up, and neither can heater.

Next time engine is warmed up, set Heat to Hot, pop the hood and feel the two heater hoses that go into the core/firewall.
Leave engine idling.
Both should be warm but one will be warmer than the other.
The warmer one is the IN hose, the other is the OUT hose, remember or mark which is which.
If the OUT hose is much cooler then either the heater core is clogging up or the heat Valve is not opening all the way.

Not sure on a 2008 but you probably have a Heat Valve(2 connections) or By-pass Valve(4 connections) on the heater hoses.
Usually vacuum controlled, take note of the position of the valve arm now, remove vacuum hose and valve should close, see if you can move the valve manually to open more than it was before.
If you can then hold it there and feel the OUT hose again, it should be getting warmer, if so you have a vacuum leak in the heat control or a bad valve.
To check for bad valve put a vacuum hose on it and suck on it, valve should open all the way and stay there until you release the vacuum, engine can be off for this test.
If valve checks out as OK then you have a vacuum leak, which can be hard to track down on these systems because if can be behind the dash on the selector.

If vacuum valve seems to be working, opens full, you will need to Back Flush the heater core.
Loads of videos on Back Flushing heater cores.

Basically you need to drain some coolant out, not alot.
Cold engine.
Remove the IN and OUT hoses at the engine end, not the firewall, remember which went where, mark it or take a picture.
Point the IN hose down at the ground or towards a bucket if you want to see what comes out.
Hold running garden hose to the end of the OUT hose, start off with slow flow and increase as you feel is needed.
If flow is restricted you will know
Flush until flow is good
If you think you need to clean out the core more, i.e. flow is not great.
Blow out the water in the core, you can just blow in either of the hoses, doesn't have to be dry, just most of the water out.
Mix some warm water and CLR, pour it into the core, let it sit for 20min. then flush again.
Repeat as you see fit.

Last edited by RonD; 12-02-2014 at 02:07 PM.
Reply With Quote
Old 12-02-2014
Bob C. of Indiana's Avatar
Join Date: Oct 2012
Location: Central ,Indiana
Posts: 217
Reply With Quote
Old 12-03-2014
iTrader: (2)
Join Date: May 2014
Location: Lake Mary, Florida
Posts: 349
I can agree with RonD that the heater hoses can be a great indicator as to if you have warm/hot water arriving to the heater core. I had to bypass my heater core for now, as it was leaking, and I have not scheduled the time (yet) to replace the core (a PITA to pull the dash back to get to it; 2000 Ford Ranger). The brass fittings I used to create a "U" for this bypass get hot to the touch, telling me that when I do replace the core, I'll have plenty of heat!

Another thing to ask: did you, or a previous owner put a lower temp thermostat in the engine? This is ill advised, as the engine creates more pollutants, and the oil will contaminate quicker, as the engine does not reach correct operating temps to run efficiantly.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Heater not working/not shifting right conrad General Technical & Electrical 7 01-20-2011 06:35 PM
My fitty, well not for much longer, but for right meow ATOM Snapshots 44 08-25-2009 01:42 PM
Heater still not working k.blakeley General Ford Ranger Discussion 14 02-22-2008 08:09 PM
Heater not working and running a little hotter bmxrider379 4.0L OHV & SOHC V6 Tech 15 01-14-2007 10:38 PM
Heater not working marathon_rat General Technical & Electrical 5 11-03-2006 07:06 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -6. The time now is 01:13 PM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.