I have a 2001 Ford Mustang Bullitt that overheated, but the gauge never went over the center between hot and cold. The mechanic replaced the thermostat and checked the water pump, but the engine still runs hot. Now he thinks it may be the head gasket. Is this a reasonable assumption? Also, the fan had started making a high-pitched noise while in the off position. Could this be part of the same issue?
There are tests to confirm a leaking head gasket. This is too expensive to guess about.
Which fan are you talking about, the radiator fan or the heater/AC blower? There is no “off” position for the radiator fan. The heater/AC blower has nothing to do with the engine overheating.
How do you know it ran hot? How was it checked? Did it blow all of its coolant out the exhaust, or onto the ground? Does the exhaust smell somewhat like maple syrup?
Your mechanic needs to do a check for carbon monoxide in the cooling system before he/she charges you many hunderds of dollars for a head gasket job. IF he doesn’t have the tool, he can “rent” it on Auotzone’s tool loan program. He will have to BUY the reagent for the check, but he’ll have enough left over for several additiional cars. I think it’s an 8oz bottle for about $8, and each test uses 1 ounce. The gizmo has a suction bellows that draws hot air from the cooling system thru a blue liquid. If CO is present, the liquid will turn yellow.
It was the heater/AC blower. It has to be circulating the air or the high pitched whistle drives me crazy. I am taking my car to another mechanic who, hopefully, will have another answer.
I agree with MG McAnick about providing some details on the overheating (all of the time, only in town, A/C on or not, etc.) and there being tests performed to determine if a head gasket is really bad or not. A compression test, cooling system pressure test, vacuum gauge, etc. can also be used to verify the problem. It should not be an assumption at all.
This is one of those posts that irritate me a little bit about the profession. A car runs hot and possibly after a few things like T-stats, etc. the head gasket gets the blame because he thinks it may be a head gasket. It’s a pricy job so verify it before telling the customer this.
I had driven about 20 highway miles with no apparent problems. When I got into town and had to stop for stoplights, I noticed that while in neutral, the air conditioning was putting out warm/hot air. I pulled into work shortly after and there was steam coming out from under the hood. The hot/cold gauge did not move from the center. The steam was antifreeze that was bubbling out from under the cap. The thermostat was replaced and water heater checked, but the mechanic said that the engine still runs “moderately hot” at 212 degrees, while on the computer. I have been referred to another mechanic who will hopefully have access to the tools that he needs to make more than an educated guess.
Let?s take things one at a time. First the noise. I don?t think it is related to the other problem. Does the Bullitt have automatic (digital) HVAC controls or manual (knobs)? You might have a vacuum leak.
I am working on the manual control assumption, but it might also be valid for the automatic controls. When you write ?off position? do you mean fan setting to the lowest or the HVAC control in the Off position. The latter is the only position where the HVAC blower is off, but it also puts the AC compressor off, and the diverter doors in the HVAC system in particular positions. The control combines a switch for the blower and the vacuum controls for the diverter doors. Maybe you have a leak in the control, maybe you have a leak in a vacuum line or a vacuum motor that controls the doors.
Head gasket failures are unusual on those engines. I see some problems with the discussion so far. I have trouble with 212 being ?moderately hot?. The following temps are for a Crown Victoria but they should not be all that different for a Bullitt. The normal t-stat opens between 192 and 195. The low speed fan comes on at 209.
I am not sure how the temperature sensing system works in this Mustang. On some cars there is a temp sensor for the computer and one for the dash indicator. On some cars, there might be one and it is shared. Is the fan running after the engine warms up? Does it run immediately when the AC is turned on? I suspect that the temp sensor is not working. That may keep the (engine) fan from turning on. The fact that you lost AC when you are not moving is an indication that the fan is not turning.
Would that not be a test for HC (Hydacarbons) not CO?
Replace your radiator cap. A faulty cap will not maintain pressure and the coolant will boil at 212 or so at sea level.
50% glycol boils at 225 F at sea level.
Is the Bullitt edition the one that comes with six hubcaps?