My engine is over heating and will not cool back down while driving. Have flushed the coolant system, new thermostat, and new fan clutch with no difference. I'm putting in a new radiator (2 row). Anyone think it could be the water pump? When I flush the system I could see the coolant in the resevior being pulled down when I revved the engine. I can keep the temp in the operating range by turning off the A/C and slowing down but the temp will not come down unless I turn off the engine for an hour or 2 , but after about 10-15 minutes of driving the temp starts climbing. This happens during outside temps of 80 degrees and higher. When its cooler it runs normal (about 1/3rd on the instrument gauge).

97 XLT
4.2 5-speed
No Mods done
63k miles

 

OK Overheating or running on the warm side of NORMAL?

Big difference in which one it is.

Does it lose coolant?

There are several parts to this that need to be clearer. Fords don't have the most reliable analog sending units. In fact on some vehicles the manual tells you that the temperature can run all the way up on the high side of the normal range as long as it doesn't run into the red zone. particularly is hotter weather and stop and go traffic.

Now having said this what to do?

You probably are running a 195 thermostat. If you don't have a meat thermometer you can nicely convince the wife to let you use, either go buy one or go to a shop and actually measure the coolant temperature. I found that the whole range of normal on your gauge may only cover like only 15 degrees in temperature.

If the water temp (or the thermostat housing) is 195 when you verify it with a thermometer then I'd say you have nothing to worry about.

When you flushed it, did you drain and refill? If you drained did you measure the amount of coolant put back in? Check the capacities in your manual to see how much it is SUPPOSED to take on. If you have a clogged or bad radiator, it won't take on the full capacity and that would help you dtermine the radiator is bad.

No I don't think your water pump is bad. They either move water or they don't. If it doesn't have a leaky seal then I'd say its working based on what you said. Impellers are fixed things. They either are there or are broken off. You'd know the difference. It takes many more miles than you have to physically corrode them away.

But if you are in fact overheating PLUS consuming water, that is a sign of a headgasket leaking. You'd also could or can see steam coming out the tailpipe like a steam machine. Not yet if it is still a minor leak, but it is coming.

Otherwise I'd lean more towards a raditor or raditor cap.

You can have a system pressure checked by a reputable mechnaic. If it passes the pressure test, you have a more minor problem rather than major one.

God luck and don't ingore that you need to know more info. Heat will kill the heads on these engines.

Tom

 

The coolant system does not leak any where and when the temp goes up it usually stays in the high normal and it will go into the red then I turn the engine off. It seemed not to take what the manual says for coolant (17 quarts) it took 3 and 1/2 jugs (4 quarts each) so it could the radiator is clogged. Thanks for the info.

 

It isn't likely you completely drained your block dry, so you are talking about 3 to 4 quarts possibly in what isn't matching up. This isn't much of a difference to hang your hat on.

Make sure there isn't any air pockets from your flush and fill.

Do a pressure check. Since it is going into the red you definitely need to track it down.

When it is getting hot do you verify that your fan is blowing. Changing it is fine but make sure it is in fact working.

I don't mean to sound like I am thinking you are an idiot. Simple things elude the best of us sometimes.

Trust me I have spent days repairing things that were never the cause. It was simple things I was sure it couldn't have been...:-).

Like a bad raditor cap. That one got me real good after I changed water pumps, radiators and thermostats.

 

How could a radiator cap cause a over heat? cause it is not sealing properly? Anyway the radiator is next. Thanks again for the info.

 

A new 2 rod radiator fixxed it. Had a 1 rod in the truck origially and put a 2 rod in. Only 5 bucks more. I took it for a one hour drive and the temp never climbed up the 1/3 range. Hopefully this will do it.