overheating

M

Marine

Registered
So someone please check my logic here. I came back from D.C., my wife picks me up in the lincoln and it overheats. This is the first time i've had it over heat. It was real close to the red line. So I pull over and ensure that everything is plugged in. I let it cool and limp home. So today I pull the filler plug off the crossover and start the car(which is already at operating temp) and observe coolant flowing in the crossover. So I pull the plug from the temp sending unit and try grounding it to see if I can get the fan to turn on. I have also checked the fuses under the hood, and all are fine. I pull the plug off the fan and start the car, and when it gets to the temp range that the fan usually kicks in, I test for voltage at the fan plug. I am getting 12.8 or so volts. So, I have power to the fan at operating temp, but no fan. The blade spins easily, the motor isn't locked up. So of course my logic says "replace the fan genius!" Does anyone see any flaws in my diagnostics? Does anyone know where I can pick up a fan? Remember, I'm in Hawaii and there's like 3 other Mark VIII's out here. Junkyards dont really exist. What other FoMoCo products share our fan??
 
RE: overheating

Autozone sells the fan motor for $94. Lifetime Warrenty, new not rebuilt. Thats cheaper than I seen some of them going for on the salvage yards. I don't think that there any other cars that share the same fan as our car, but I'm not sure. I know its a highly sought after part because its so efficient.
 
RE: overheating

The other possibility is a bad ground or a fault in the VCRM. The VCRM controls the fan and it is possible to have voltage but not enough current capacity to drive the motor. Unlikely but possible. The other possibility is a corroded ground. The fan shares ground connection G103 on the drivers side header panel underneath the plastic shroud covering the headlamps. You will find 3 grounds, 2 on the drivers side and 1 on the passenger side.
 
RE: overheating

what's the vcrm? and is there a way to diagnose this? Is there a way to test my motor? just run a power and ground wire to it right?
 
RE: overheating

It does sound like a fan.

I take it she was sitting in one place waiting to pick you up, and there is no overheating when you're cruising down the road?

I'm sure you can order a fan from any number of online discount sources. Just a couple extra bucks for shipping. Probably won't even cost as much as a normal dealer!
 
RE: overheating

the fan does not kick on at all. She wasnt just sitting there. I think it's the fan too. I have a friend who has a 94ish t-bird lx with the 3.8 V-6. I looked at his fan and it looked identical. Does anyone know if it's the same?
 
RE: overheating

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I have a friend who has a 94ish t-bird lx with the 3.8 V-6. I looked at his fan and it looked identical. Does anyone know if it's the same?
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i don't think it is, but i'm not sure.
 
RE: overheating

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the fan does not kick on at all. She wasnt just sitting there. I think it's the fan too. I have a friend who has a 94ish t-bird lx with the 3.8 V-6. I looked at his fan and it looked identical. Does anyone know if it's the same?
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What? You gonna 'borrow' it?! :+

Take some wire and jerry rig power and ground from the battery to the fan motor terminals with the harness disconnected(Note the black wire in the harness is ground, the light blue is power and the third wire is nothing). If the fan runs, it's a bad ground or VCRM(Variable Control Relay Module) - i.e. no ground or no power from the VCRM. The VCRM is a solid state variable voltage feed for the fan to operate the fan from 50% to 100% as dictated by the PCM and AC functions. If the AC is on the fan should be on lo at a minimum(50% of battery voltage). I tested the temp the fan comes on with the AC off - not until 215 degrees IIRC. When the fan comes on for cooling reasons only it is at 100%(full battery voltage). And of course the PCM tells the VCRM to shut down the fan if vehicle speed is maintained above 45 mph.
 
RE: overheating

I havent tested the fan yet, with battery power, but I'm curious as to how to test the vcrm, as well as how to locate, and if necessary replace it?
 
RE: overheating

Locating it is easy enough. Testing is best done with a known good replacement since it is a solid state device.

It is located behind the grille down low towards the drivers side of center. A brick sized module with cooling fins.
 
RE: overheating

One thing I'll recomend, pull the plug off your fan and take a look to see if anything is scorched. I actually had the windings come loose on one of the stators in the motor. This caused it to short out my plug and i needed a plug rebuilt kit and a new fan. I just called Max at Five Star (Dan had just been laid off from JC) and had the new fan in 2 days. One of my friends is currently rebuilding the fan for more flow.
 
RE: overheating

So I ran some leads to the fan and Viola! it works. Now what boggles me is how I can have power at the connection, but no fan. I am getting 12 volts at the harness but still no fan. WTF??
 
RE: overheating

[div class="dcquote"][strong]Quote[/strong]
So I ran some leads to the fan and Viola! it works. Now what boggles me is how I can have power at the connection, but no fan. I am getting 12 volts at the harness but still no fan. WTF??
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2 possibilities exist.

1. The VCRM is delivering voltage but not amperage to run the motor. It is possible to 'measure' battery voltage but still not have current capacity to operate the motor. This phenomenon is more often seen in blown hi-amperage fuses which read good with a continuity meter but will not conduct enough current for the circuit.

2. When the harness is plugged in, there is a fault in the ground. Did you check the voltage using the ground wire terminal at the harness? A popular mistake when troubleshooting DC electrical circuits is unintentionally ignoring the ground path. If for example the positive lead of the tester was on the harness power wire while the negative lead was connected to the battery ground or some other ground point it would indicate proper voltage even though the ground wire in the harness for that circuit is open.
 
RE: overheating

I tested it on the harness, using the outer terminal as the ground. On the opposite side was the power. I am guessing that it's the amperage. Thanks for the help. I have located another VCRM and it's on it's way to Hawaii.
 
RE: overheating

I would recommend replacing the thermostat if you haven't replaced it before. Mine failed closed intemittently several times before I figured out what it was and changed it. My son's 95 Mustang's thermostat failed closed at about the same mileage 70 to 80K. The Mustang V6 blows head gaskets when this happens and it cost $1200 or so to fix the Mustang. The audible alarm on the Lincoln saved me from overheating the Mark to the point of harming it.

Roadie
95 Champagne Mark VIII
00 Ford F150 Supercab 4x4
02 Mazda Protege
86 Chevy Monte Carlo SS
81 Honda CB900C
 
RE: overheating

Chalk me up for a bad VCRM (sometimes called a CCRM in other Ford products). Now my fan works, at $180 later. :(

Sad thing is, my engine occasionally still overheats (or gets on up there, high).

Next step (since fan and air flow checks out): Thermostat

-Eric
 
RE: overheating

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Next thing is probably to insue it is REALLY full of coolent. Do NOT think that a full overflow tank is a full cooling system.Bud Pytko'97 LSC Silver Frost'92 F250 Banks TurboDiesel Bimini Blue'92 Prowler 5th Wheelhttp://myfilelocker.comcast.net/charlespytko/Lincoln/BudPytko97LSC.JPG
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It be full.
 
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