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Last year the heat stopped working. 93 2wd 4.0l, rear heat/AC. Temp gauge fluctuates between N and L quite a bit. Coolant is full, but does lose some. Goes up to L, then drops quickly to N, then slowly back up. AC hasn't worked for a while.
Time for a thermostat? New heater core? Doesn't seem to be coolant in the oil. It is now the spare vehicle, but winter is coming. Don't feel like scraping the inside of the windshield anymore.
Last edited by MFJ; Sep 12, 2008 at 03:26 PM.
Reason: Vehicle description added
Is that a symptom of a stuck open t-stat? Mine started doing that right after I did a major flush. I always thought it was air that I could not purge from the system. My previous experience with a stuck open t-stat prevented the engine (and heater) from warming up in the winter. This one does not.
How much of a pain is the T-stat on these? I hope it is not too bad.
The temp gauge moves around, a lot. My Sable and Windstar gauges are both pretty steady, and have heat (part of why the Windstar was bought, along with a working side door ).
Like anything on an Aerostar engine, the T-stat takes a bit of parts removal to get to. The bolts, especially the lower one on the housing, will require some extensions and flex joints to get to. Be careful of the wire going by that area, as it is for the crank position sensor; some people have damaged it while replacing the T-stat, and the engine won't start afterward.
... Coolant is full, but does lose some. Goes up to L, then drops quickly to N, then slowly back up.
Also acts like this when air gets in the system. Temp sensor sits at the high point and any air trapped there will cause gauge flucuations like you describe. Hard to get all the air to bleed out. If you are losing coolant, you likely have air in the system.
Got a new radiator cap, and tried to burp the system. Seems to work better now, the temp gauge doesn't swing like it used to. Still in the 70's around here, so I didn't try the heater out yet. While burping the system, a little bit of heat was there, but not like it should be. I'm thinking about taking the rear heat out of the system, less chance for leakage. The hard lines are rusty. The van is not going to be used for passenger haulage anymore for the most part. Gets cool in the back.
At that explains why the cubbyhole fills with water.