Hi,
Recently my 2.9L V6 in my 1986 Bii w/ a FM146 tranny has been running hot mostly while the engine is idle, this goes for while i am sitting at stops signs and the like, as well as at low speeds, and often while i have the clutch out and am just coasting. This all started to become really bad after the water pump died and had to be replaced. Since then I have also replaced the thermosat, and the radiator with a brand new 2 row radiator(the heavy duty radiator for a 1994 4L explorer) and the engine is still overheating. The radiator is holding coolant, it doesn't seem to be loosing any as far as i can tell, so i am not sure what the problem is. The only thing i think it could be is something i read about recently, and that is that one of my head gaskets has gone bad and i have exhaust gas leaking into the coolant, i am going to get one of those combustion leak test, but does that sound plausable, or does anyone else have any ideas as to what my problem might be, any advice would be greatly apprciated.

Thanks in Advance

 

replace the fan clutch?

 

How are you determining that the engine is overheating? The stock gauge/sender may not be accurate, have you done anything to double check it's reading? Just throwing it out there.

 

I have removed the temp sender unit and tested it by sicking it in water and heating it up to check the resistance value, and yes i have been using the stock temp sensor, but i have also taken a thermometer and stuck it in the oil, and it also confirms that the engine is getting to hot.

Any way to test if the fan clutch really needs replaceing without actuall replaceing it, because of have idled the engine for quite some time to see if maybe the fan wasn't working, and it never did stop turning.

 

One of the best tests I've found came from a Mitchell manual:

1) Remove fan clutch.
2) Disengage outer end of spring and rotate CCW 1/4 turn. This prevents the fan clutch from freewheeling.
3) Reinstall fan clutch and test drive. If overheating condition is resolved, then fan clutch needs replaced. If overheating condition still exists, then fan clutch isn't likely the problem.

On my BII, I couldn't really hear the difference, but on my Explorer, the difference in the fan sound is quite pronounced when it's engaged and disengaged.

 

have you checked the oil to make sure you don't have coolant leaking by the head gaskets? that is a very common problem on these bII's mine had the same problem in june 2005 found one head to be cracked...you also could have some internal blockage in the water passages in the heads or the block.have you tried to flush the engine out?

 

THanks for all the help i seem to have solved the problem it was a conbination of a pinched wire, and a small piece of the old water pump that broke and was in the system, and as best i could guess kept getting hung up in the engine, thus reducing the flow of coolant and causing the engine to run hot.

THanks for all the help