Heater question

12-11-2012, 04:10 PM	#1
Bigplanz Member     Join Date: Apr 2009 Location: Louisville KY Posts: 404	Heater question 95 Mercury Villager. While driving with van at full operating temperature, heat comes out at 2000 rpm but when I stop and rpms drop to 800 the air blows cool/cold. Any idea what might cause this?

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12-11-2012, 04:14 PM	#2
joecaption Member   Join Date: Nov 2011 Location: Hartfield VA Posts: 18,206	Heater question Low on water in the radiator, Partly pluged up heater core.

12-11-2012, 08:34 PM	#3
ukrkoz Member     Join Date: Dec 2010 Posts: 382	Heater question undeperforming water pump or loose pump belt. __________________

12-11-2012, 08:42 PM	#4
DexterII Member   Join Date: Jul 2010 Posts: 1,549	Heater question Could also be vacuum related, whether an engine problem or a faulty or partially crimped line, not having enough to hold the gates open at idle, effectively closing the ducts.

12-11-2012, 09:17 PM	#5
Bigplanz Member     Join Date: Apr 2009 Location: Louisville KY Posts: 404	Heater question I am reading up on this and read it could be air in the system. The recommendation is bleed or "burp" the cooling system. The factory service manual I found on-line has detailed instructions on how to do this. I'll give that a try this weekend. Might replace the belt too, while I'm at it.

12-12-2012, 01:07 PM	#6
Thurman Household Handyman   Join Date: Feb 2009 Location: Albany, Ga. Posts: 2,210	Heater question I'm with Dexter II on this one--a vacuum leak. The reason being is that you state that you have heat at 2000 RPM and lose it at 800 RPM. The lower the RPM the higher the vacuum. When you slow down to the 800 RPM area there is more vacuum and this will cause the 'air flow control panels" (doors) to move with more force. Depending on your vehicle a door is either closing or opening at the 800 RPM range and changing the air flow. A vacuum check on the entire vacuum system is at hand.

12-13-2012, 07:50 PM	#7
Bigplanz Member     Join Date: Apr 2009 Location: Louisville KY Posts: 404	Heater question From what I understand, the 95 model Villager's blend doors aren't vacuum controlled. I put some coolant in the recovery tank and heating improved. Still checking it out. I found the engine air bleed bolt and heat pipe bleed cap and read up on bleeding the system. I'll try it soon.