OK. I need a second opinion. F-150 with 144K miles. Water pump started weeping. Replaced pump and thermostat, engine is now getting hot. Removed thermostat and engine is still getting hot, around "L" or a little better. Looked in radiator and it looks like a sink draining, not alot of water flowing. Did I get a bad NEW water pump from AutoZone? I think so, but want a second opinion. Thanks, --mark

 

the fan is also drawing a considerable amount of air thru the rediator, so I feel the fan clutch is OK. Like I said, the temp was fine til the pump change.

 

Hmmm, what do you mean "looks like a sink draining"? You really shouldn't see anything.

My guess would be you have way too much air in the system. I think your model has an overflow tank which means the radiator should be full to the top with no air. If you have too much air in the system it may overheat. So you probably need to fill it up and bleed the air, if there is a bleeder.

What I do is check the overflow tank every day for about a week and top it up to the mark each morning. As the air works out of the system you will need to add fluid. After a week you should be stabilized. After a day or two the overheating should be gone.

It would be unusual for a water pump to be dead fresh out of the box, they are fairly simple things. You could check to see if it is pumping by squeezing the hoses with the engine up to temp and running. You should be able to feel the water going thru. If you rev the engine the water pressure change should be obvious.

It is not unusual for a new thermostat to be bad. I would guess over more than 30 years of tinkering I have had 2 brand new Tstats go bad right out of the box or shortly after. I would suspect that before suspecting the pump unless there were obvious symptoms of a bad pump such as leaking a lot or squeal or the pulley on the pump not turning.

Good Luck,

Jim Henderson

 

I have the overflow full and it stays full all the time. there is no thermostat in it at this point, but when I pulled the new one, it was still open. the hoses are hard as a rock when its hot, and no indication of flow at all. i have driven the thing around 100 miles at highway speeds also, shouldnt that burp all the air out? I can't imagine the water pump is bad, but it was the only thing changed.

The sink draining analogy is what i see when looking into the radiator fill on the radiator with no thermostat in. Thanks for the reply and any help is appreciated greatly. --mark

 

Make sure you got a reverse rotation water pump, and that you have the serpentine belt on correctly. The serpentine belt system requires a reverse rotation water pump.

 

I will check the belt. I have the old pump and will take it with me today and compare it to one of theirs in stock. I can see the find in the old pump and if theirs it different it should be obvious. And if it is the belt, I will never admit it! Kidding. I appreciate the fast responses on this board again. --mark

 

Fill the radiator, then put the cap back on loosely. Only tighten it one 'click' so that air can escape. Then start the engine, let it run to hot, and this will force all the air out. Then tighten the cap all the way.

Also, be sure you get a thermostat with the small hole in the mounting circle, like the OEM thermostat. This hole goes on top when placing the thermostat into its mounting hole. This hole allows air to escape so the system bleeds air itself. I got a thermostat at NAPA that didn't have the OEM hole, and it never settled down.

 

Upon further review, I know the belt is on correctly as the air is being drawn rearward thru the radiator. Fan turning right, pump turning right. I am taking the old one to Auto Zone today and gioing to compare parts and look for a piece of paper that I probably ignored last week that says "if serpantine belt is used, reverse rotation of impeller"or something like that. That has got to be it. Will know by tomorrow. Thanks for the responses. --mark

 

update: Changed the water pump, just because i convinced Auto Zone it was leaking, and installed it to Haynes spec or 18 ft lbs of torque, and installed new thermostat. Engine got hot on test drive and friend is telling me to give it a day or two to remove all the air from the system. I will, but I noticed that I do not hear the "roar" from the fan clutch that the Haynes manual describes when the engine is hot. Should the fan be locked to the water pump when the engine is very hot. It is turning, but possibly not enough?

 

You should DEFINITELY hear the fan when the engine is hot and the RPM's are up, even over a roaring a/c blower. At about 3500-4000 RPM's ( engine hot ) it should sound like -- well allot of air I guess. I know this from pulling a boat, 100+ temp. and A/C on max. The fan will engage for about 10 seconds then you can watch the temp. go down. As far as trouble shooting the clutch I don't know the proper procedure, but 144K miles it's probably getting due. This may sound stupid, but is the fan on backwards. It will still blow air in the same direction, just not much volume.

 

Just drove the truck into work this AM and not overheating at all. Please note: outside temp in Tulsa is 70 now, not the 100 it was yesterday afternoon. I bet the same drive this afternoon shows the engine getting hotter. I am really looking at that quiet fan clutch. I am considering rigging it up this afternoon to run all the time by connecting it to the shaft that connects it to the water pump. Does anyone know if there is an adapter that can make it a direct drive fan and what are the drawbacks. I assume slower warmups in the winter is a big one.

 

Try this,

When the engine gets hot and you get home, spray the radiator with the garden hose and watch as the water evaporates. this will show any cold spots (plugged spots) in you radiator, or uneven cooling because of a plugged radiator. I had this problemon my other truck and a $25 radiator cleaning is all it took to bring the temps down. Also I remember that when I changed my partially bulging hoses, I lowered my temp a few degrees.

Just some more Ideas,

 

did you add stopleak before changing the pump.if so, have your system flushed, its most likely clogged somewhere.

 

No, I saw the water pump leaking and changed it immediately, now twice. The heatwave here started around the same time as the overheating started. I have a 87 Mustang GT that utilizes the same fan clutch as verified by Auto Zone, so I am swapping the two this afternoon. If that gets it, the Mustang will get a new one.

 

[QUOTE]Originally posted by markcrane
I am really looking at that quiet fan clutch. I am considering rigging it up this afternoon to run all the time by connecting it to the shaft that connects it to the water pump.
...

Went down this same route when my truck was getting hot and leaking coolant. Thought it was the fan clutch cause it didn't seem like it was turning fast enough.

But the fan clutch is a vicuous clutch... there is fluid in it that gets thicker as it heats up, and this causes the fan to slip less and less on the clutch as temperatures rise. When the clutch is very hot, it is still not 100% direct drive. That reduces stress on the water pump.

The fan clutch is very very reliable and very rarely fails. I'd look elsewhere, like making sure the radiator is clear. Remove it, turn it upside down, and back flush with a hose with strong pressure. You'll be amazed at the gunk that flushes out. Also check that the fan is on the right way... easy to reverse it.