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View Full Version : More car questions(engine/cooling questions)


dremen
11-09-2010, 05:12 PM
Well I know a few people here know there way around an engine so im going to look for some feedback here.

Ok I have an early 90's ford car 3litre V6 engine and it runs great, it's not that bad on gas and it still has a LOT of power for an older car, but the heating/cooling systems are starting to give me some headaches.

So right now the problem is with the heating system. When I turn the heat on in the "vent" position it works like it should and pumps out an assload of heat, BUT when I put the heat in either the "floor"/"mix"/"dash" heat positions it still works, but the air conditioner tries to keep turning on.

What I mean by that is the disk that engages to run the ac motor clicks on then off repeatedly, but only when the heat is in the floor/mix/dash position. So of course this causes the engine to be overworked and a TON of gas to be eaten up so I keep the heat in the vent position when heat is needed.

Anyone here know why the ac would keep trying to click on when the heat is in those 3 positions and NOT when it's in the vent position?

This is really weird and just started up on me a few weeks ago.

Thanks for any input on this.
RagingRandy
11-09-2010, 07:44 PM
Not sure what the issue is but the AC is supposed to kick on when the defrost is on, I believe. This boosts the fan and helps remove humidity. It seems like there is a flaky sensor in your control. However I am not sure where you should start looking.
Forever
12-09-2010, 05:18 PM
As RagingRandy said for the defrost/mix (maybe the floor too, I'm not familiar with the specifics of your car) the air conditioner is supposed to fire up to remove humidity so the windshield clears quickly.

Does your air conditioning still blow ice cold air and otherwise work the way it always has?
There should be a low pressure sensor in the AC system that will stop the clutch from engaging (or disengage it if its engaged) when there is low pressure in the system. This stops the compressor from spinning dry and killing itself (there is a lubrication oil in the refrigerant).