Fan Clutch removal

[James Meeks]

I find it necessary to remove my fan clutch to make room for other maintenance. My Chilton's states that the 2003 4.0 L engine can be either right or left hand threads, and instructs the reader to examine the exposed threads to determine which I have. However there are no exposed threads. Is there a way to tell from the truck serial number?

 

[96firephoenix]

You don't have any exposed threads? that's odd. Mine has about 3/4 inch (2 cm-ish). What exactly does the chilton's manual say?

For what it's worth, the water pump can be removed without taking off the fan or clutch. once off, it is easier to apply gentler torque. I'm doing an e-fan conversion while I've got the whole thing apart, so I didn't really care about the threads.

 

[James Meeks]

Thank you firephoenix, for your response. I finally decided it had left hand threads and with more torque than I thought necessary it came off.
Perhaps you might offer some more advice; I blew a head gasket at #6 cyl to the outside(not to the water jacket). If I have to get the head milled do I also have to get the undamaged head milled?

 

[imp]

Thank you firephoenix, for your response. I finally decided it had left hand threads and with more torque than I thought necessary it came off.
Perhaps you might offer some more advice; I blew a head gasket at #6 cyl to the outside(not to the water jacket). If I have to get the head milled do I also have to get the undamaged head milled?

@James Meeks
Milling one head only will somewhat upset the "balance of the engine, as milling increases the Compression Ratio, thereby increasing slightly the pressure and power developed by that side of the engine. So, yes, milling only one head would be strongly discouraged.

However, if you hear the blown gasket's leakage, and the vehicle has not been driven too long with the leak present, what leads you to believe the head's surface would require resurfacing? Sounds like a possible selling of service scheme. If it were mine, I would have a guy having a "sniffer" check the space above the radiator coolant, while the engine is running, for unburned hydrocarbons, the presence of which indicates gasket leakage (or a minute crack) of combustion gases into the water jacket. A positive finding might indicate greater cause for alarm. OTOH, a combustion leak of any significance over-pressurizes the cooling system, and causes loss of coolant (and gas) via the radiator cap. The condition of the head gasket, inspected very carefully, can reveal much to add to the conclusions, as will the head (and block) surface.

Repairing the engine, unless done yourself (i.e., no labor cost) will likely come very close to the vehicle's market value. imp

 

[Number Twelve]

Short version: Head gaskets sometimes fail. You don't have any reason to believe anything else is wrong until you take the head off and start measuring for flatness and looking for eroded areas in the metal. You have to take the head off, no matter what the problem is, so start with that. Everything else is guessing until you get that head belly up.

 

[96firephoenix]

Thank you firephoenix, for your response. I finally decided it had left hand threads and with more torque than I thought necessary it came off.
Perhaps you might offer some more advice; I blew a head gasket at #6 cyl to the outside(not to the water jacket). If I have to get the head milled do I also have to get the undamaged head milled?

Is the leak on the Passenger's or Driver's side head? The Passenger head on a 4.0 can't come out while the engine is mated to the transmission.

I don't imagine you'd need to get the head milled just for a blown head gasket. Imp is right that it will upset the balance of power in the engine... not by much, but I think you'd be running kinda rough... risk of long-term damage is pretty great.

I'll second the assessment Imp made about the repair cost and the value of the vehicle. I'm $2300 into a new engine and random incidentals (i.e. motor mounts, serp belt, etc...) on my 02 explorer.

The way I'm looking at it is that I couldn't get one in the same condition for $2300 (I know this because I paid that for mine before making a lot of repairs). I certainly couldn't get one in that same condition with a freshly rebuilt engine for $2300, so Comparing to the ones that claim freshly rebuilt engines on the ad and seeing that they were more than $2300 more than I had in the car already, I elected to replace the engine.

 

[James Meeks]

Thank you all very much for your input. When I got the head off (Drivers side) I discovered the real problem. A broken valve spring on #6. Too bad, I could have saved myself a lot of trouble if I had seen it earlier.