Hit-or-Miss Heating
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From: dsi1 on 14 Dec 2009 18:44 On 12/14/2009 11:37 AM, hls wrote: > > "dsi1" <dsi1(a)humuhumunukunukuapuapa.org> wrote in message news:jKxVm.46756 >> I don't think there's any problem with coolant flow through the heater >> core. I'll bet your problem is the blend door in the heater box. I >> don't know how you would check/repair something like that. > > I dont know about Sable. On some cars you can get to them well enough to > manually operate the doors. If they are vacuum operated, you have > another burden to bear. I don't know anything about these systems because in the past, if it went bad, I'd just run without the heater. The idea of working under the dash is pretty unappealing - thank God I live in the tropics. My guess is that the Ford uses vac servos to operate the doors and one could do an initial check with a hand held vacuum pump. I'll bet the system tends to leak when the rubber hoses are cold. > > If the doors are stuck, you can sometimes free up the mechanical pivots > of the blend doors with a little shot of aerosol lubricant. > A Sable mechanic would likely know all the systems. > > I dont understand why this system would work in the afternoons, but not > in the mornings,and now wont work at all. I am sure it will make sense once > he gets into it > > Really helps to have a good manual when you are trying to DIY something > like this.
From: hls on 14 Dec 2009 18:59 "dsi1" <dsi1(a)humuhumunukunukuapuapa.org> wrote in message news:d5AVm.80866 > > I don't know anything about these systems because in the past, if it went > bad, I'd just run without the heater. The idea of working under the dash > is pretty unappealing - thank God I live in the tropics. My guess is that > the Ford uses vac servos to operate the doors and one could do an initial > check with a hand held vacuum pump. I'll bet the system tends to leak when > the rubber hoses are cold. There are different systems and you really have to know what you are doing. Some GM systems, for example, us a vacuum modulator module that is a little difficult to diagnose without the proper tools,and is DAMNED expensive to replace. This system operates blend doors, etc. Sables and Tearasses are just something I dont know anything about, and really dont want to learn. I wish it were as simple as it used to be, with just a manual linkage to the blend doors, a simple valve, etc. But it isnt always that way. mvh
From: Jack Myers on 15 Dec 2009 01:47 dsi1 <dsi1(a)humuhumunukunukuapuapa.org> wrote: > On 12/14/2009 6:51 AM, J.B. Wood wrote: > > 2. There have been several isolated instances where the temperature > > indicator (engine has been running for a while) has gone to its maximum > > value and just as quickly dropped down below below the midpoint before > > returning to the midpoint. My conclusion here would be low coolant but > > the coolant appears to be full. I'm speculating that something is > > restricting coolant flow such as a partially-blocked radiator or > > somewhere else other than the heater core but before the thermostat. Any > > further insights are most welcome. Sincerely, > > > You should verify that your coolant level is OK and there's no leaks. If > that's the case, change your thermostat. I think that your heater > problem is unrelated to your coolant problem. It certainly sounds like an air bubble. Just to be sure, are you checking the coolant level in the cooling system itself rather than in the overflow tank? Wait until the engine is dead cold and then remove the remove the pressure cap. Top it up. After the initial fill you need to "burp" it--run it through a full temperature cycle with the heater on-- then top it up again. After that you can leave the cooling system sealed and simply watch the fill lines on the overflow tank. then "burp" it. h -- Jack Myers / Westminster, California, USA An expert is a person who has made all the mistakes that can be made in a very narrow field.. - Niels Bohr
From: dsi1 on 15 Dec 2009 05:17 On 12/14/2009 8:47 PM, Jack Myers wrote: > dsi1<dsi1(a)humuhumunukunukuapuapa.org> wrote: > > >> On 12/14/2009 6:51 AM, J.B. Wood wrote: > >>> 2. There have been several isolated instances where the temperature >>> indicator (engine has been running for a while) has gone to its maximum >>> value and just as quickly dropped down below below the midpoint before >>> returning to the midpoint. My conclusion here would be low coolant but >>> the coolant appears to be full. I'm speculating that something is >>> restricting coolant flow such as a partially-blocked radiator or >>> somewhere else other than the heater core but before the thermostat. Any >>> further insights are most welcome. Sincerely, >>> > >> You should verify that your coolant level is OK and there's no leaks. If >> that's the case, change your thermostat. I think that your heater >> problem is unrelated to your coolant problem. > > It certainly sounds like an air bubble. Just to be sure, are you checking > the coolant level in the cooling system itself rather than in the > overflow tank? Wait until the engine is dead cold and then remove the > remove the pressure cap. Top it up. After the initial fill you need to > "burp" it--run it through a full temperature cycle with the heater on-- > then top it up again. After that you can leave the cooling system > sealed and simply watch the fill lines on the overflow tank. > > then "burp" it. h It's surprisingly tricky to fill radiators these days because they tend to be lower than the top of the engine. On my Taurus, I can tell if it's full by squeezing the top radiator hose. The first time I changed the coolant in the car, I loosened the clap on the hose that went to the top of the engine. Now days I don't bother - I'll just run it through several heating a cooling cycles and purge air bubbles by squeezing the hose.
From: m6onz5a on 15 Dec 2009 11:34
On Dec 14, 6:59 am, "J.B. Wood" <john.w...(a)nrl.navy.mil> wrote: > Hello, all. My 1990 Mercury Sable has lately been displaying some > unusual heating behavior: With the passenger compartment temperature > set at 85F I only get cold air coming out of any of the ducts even when > the engine temp is nominal (mid range on the temp gauge). The weird > thing is that after I drive the car to work and it sits outside all day > I always have loads of heat available when driving home. The coolant > level is where it should be and the water pump and thermostat were > recently replaced. Does anyone have an idea? Thanks for your time and > comment. Sincerely, > -- > John Wood (Code 5550) e-mail: w...(a)itd.nrl.navy.mil > > Naval Research Laboratory > 4555 Overlook Avenue, SW > Washington, DC 20375-5337 I just read a couple of TSB's on the blend door having issues with the cable etc.. It also mentioned something to the effect if you are having a problem with the blend door turn the key off and back on and see if it works then. |