Heater issue
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Junior User
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Heater issue
Hi all, I have developed a heater issue I hope someone can shed some light on. My manual heat/cold adjustment dial is working fine and transitions from heat to cold readily. However when in max heat, it is blowing luke warm. The higher the RPMs going down the road the warmer it blows (still not near as hot as normal), then idling at stop lights or in park it goes back to warm only.
My engine temperature is running normal at all RPM levels while driving and idling. Partially clogged heater core maybe, where higher RPMs force more water through it? I assume its not the water pump or thermostat since my operating temperature is staying normal.
Thanks in advance for any input.
My engine temperature is running normal at all RPM levels while driving and idling. Partially clogged heater core maybe, where higher RPMs force more water through it? I assume its not the water pump or thermostat since my operating temperature is staying normal.
Thanks in advance for any input.
Junior User
Joined: May 2010
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Good Question!, My truck does almost the same think besides it only is "luke warm" heat, It doesn't warm up as the rev's go up. I would have to say either the thermostat of perhaps a heater core issue, Im sure someone with more knowledge will chime on in and help ya better, hope you can get her fixed!
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
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From: Stephensville WI
If engine temp is normal, then you're probably looking at a heater core issue.
You might try disconnecting the heater hoses and back flushing the core with a garden hose, but hard to say if that will help.
You might try disconnecting the heater hoses and back flushing the core with a garden hose, but hard to say if that will help.
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Junior User
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That's what I was assuming was the problem. Might look and see if there are any cleaners for the coolant system I can run through it. I'm guessing since it's not leaking it shouldn't need replaced if I can clean it, if that is indeed the cause?
Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
I would not trust the factory temp gauge in the cluster.
You need to know just how hot it really is. The easy answer
would be the T-stat. But lets not start by pitching parts at it.
When was the last time it was changed anyway? 2000 is a long time.
You can use the hand temp test on the upper radiator hose and see
if it is getting hot or not. One of the the heater hoses should also be
almost as hot the other one a little less. A non contact thermometer
would be handy to check the hose temps.
Post back if you can get some temps
Sean
You need to know just how hot it really is. The easy answer
would be the T-stat. But lets not start by pitching parts at it.
When was the last time it was changed anyway? 2000 is a long time.
You can use the hand temp test on the upper radiator hose and see
if it is getting hot or not. One of the the heater hoses should also be
almost as hot the other one a little less. A non contact thermometer
would be handy to check the hose temps.
Post back if you can get some temps
Sean
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Joined: Jan 2004
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From: St Louis
Not necessarily. The water is going to flow easiest through the path of least resistance. That would be the radiator versus the heater core.
If both of the hoses to the heater core are hot and remain hot (one might be slightly less so) when the blower runs at various speeds, then there is nothing wrong with the cooling system. This takes some careful observation and attention to detail to make this distinction.
If both of the hoses to the heater core are hot and remain hot (one might be slightly less so) when the blower runs at various speeds, then there is nothing wrong with the cooling system. This takes some careful observation and attention to detail to make this distinction.
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Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
Several things could be contributing to this problem. First lets start off by finding how many miles are on this rig? Do you know when the cooling system was last flushed?
Step 1. Do you get heat in any of the dash control selections- Defrost, foot, vent etc...If you get heat out of one set of ducts but not the other the selector is faulty the blend door servo could be faulty or you have a vacuum leak down at the hubs if you have that auto 4wd system. Though usually the vac leak causes the selection to default to defrost mode and you still have heat...so not likely your problem.
2. Hows the coolant level? Low level will cause this symptom.
3. Next Id say its time to do a COMPLETE flush including removing the heater core lines and putting a garden hose on each line (careful not too much pressure). Any mud come out? Replace the T-stat with a Stant HD not the light standard duty. Bolt it back up with premixed coolant or 50/50 cut with Distilled or RO water only not tap H20.
4. Still no heat? Then Id look at the blend door servo motor. I did a write up on that. Its in the tech area.
Please follow up with what the fix was.
Step 1. Do you get heat in any of the dash control selections- Defrost, foot, vent etc...If you get heat out of one set of ducts but not the other the selector is faulty the blend door servo could be faulty or you have a vacuum leak down at the hubs if you have that auto 4wd system. Though usually the vac leak causes the selection to default to defrost mode and you still have heat...so not likely your problem.
2. Hows the coolant level? Low level will cause this symptom.
3. Next Id say its time to do a COMPLETE flush including removing the heater core lines and putting a garden hose on each line (careful not too much pressure). Any mud come out? Replace the T-stat with a Stant HD not the light standard duty. Bolt it back up with premixed coolant or 50/50 cut with Distilled or RO water only not tap H20.
4. Still no heat? Then Id look at the blend door servo motor. I did a write up on that. Its in the tech area.
Please follow up with what the fix was.
Last edited by droldsmorland; Apr 16, 2013 at 05:19 PM. Reason: Posted to use DI water which is incorrect. RO or Distilled only!
Senior User
Joined: May 2012
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From: Derby, ks
i was thinking the servo blend door also.. also the vacume lines.. its not uncommon for them to crack and leak out.. my 89 mustang and 96 accent and recent 04 250 did the same. changed all the vacume lines and presto.. hot hot heat.. its not necesarily the vacume line but the fitting that connect to the door and valves.. the angled little rubber hoses that start to rot like the PCV angle does on most cars/trucks in the engine bay.. just my .02 but i have had three cars/trucks do it all of diff makes and models with the same outcome.. but i also did droldsmorland's write up and that helped it even more
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
Several things could be contributing to this problem. First lets start off by finding how many miles are on this rig? Do you know when the cooling system was last flushed?
Step 1. Do you get heat in any of the dash control selections- Defrost, foot, vent etc...If you get heat out of one set of ducts but not the other the selector is faulty the blend door servo could be faulty or you have a vacuum leak down at the hubs if you have that auto 4wd system. Though usually the vac leak causes the selection to default to defrost mode and you still have heat...so not likely your problem.
2. Hows the coolant level? Low level will cause this symptom.
3. Next Id say its time to do a COMPLETE flush including removing the heater core lines and putting a garden hose on each line (careful not too much pressure). Any mud come out? Replace the T-stat with a Stant HD not the light standard duty. Bolt it back up with premixed coolant or 50/50 cut with DI or RO water only not tap H20.
4. Still no heat? Then Id look at the blend door servo motor. I did a write up on that. Its in the tech area.
Please follow up with what the fix was.
Step 1. Do you get heat in any of the dash control selections- Defrost, foot, vent etc...If you get heat out of one set of ducts but not the other the selector is faulty the blend door servo could be faulty or you have a vacuum leak down at the hubs if you have that auto 4wd system. Though usually the vac leak causes the selection to default to defrost mode and you still have heat...so not likely your problem.
2. Hows the coolant level? Low level will cause this symptom.
3. Next Id say its time to do a COMPLETE flush including removing the heater core lines and putting a garden hose on each line (careful not too much pressure). Any mud come out? Replace the T-stat with a Stant HD not the light standard duty. Bolt it back up with premixed coolant or 50/50 cut with DI or RO water only not tap H20.
4. Still no heat? Then Id look at the blend door servo motor. I did a write up on that. Its in the tech area.
Please follow up with what the fix was.
is safe. The DI water is very active in pulling minerals from things and is
classed as corrosive. There are some metals that it won't harm and so
that it loves to eat. Do you want to take that chance? DI water has anick
name it's universal solvent.
Sean
Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
[QUOTE=Yahiko;13070567]NEVER NEVER use DI water (Deionized Water) Distilled or Reverse Osmosis
is safe. The DI water is very active in pulling minerals from things and is
classed as corrosive. There are some metals that it won't harm and so
that it loves to eat. Do you want to take that chance? DI water has anick
name it's universal solvent.
Sean[/QUOTE
OOPS you got me on that one. Yes RO or Distilled. I typed DI and meant DIstilled. Thanks for correcting me(us)! Ill edit the post to reflect. Thats why I simply suggest the premixed no guessing 50/50 with properly filtered water.
is safe. The DI water is very active in pulling minerals from things and is
classed as corrosive. There are some metals that it won't harm and so
that it loves to eat. Do you want to take that chance? DI water has anick
name it's universal solvent.
Sean
[/QUOTEOOPS you got me on that one. Yes RO or Distilled. I typed DI and meant DIstilled. Thanks for correcting me(us)! Ill edit the post to reflect. Thats why I simply suggest the premixed no guessing 50/50 with properly filtered water.
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