I have a 2000, F150 V6 truck with 150, 000 miles. On a recent two-hour trip I noticed the temperature gauge was indicating hotter than normal. If I drove the truck faster than 65 mph, the needle would get a little over three quarters of the way up to the hot symbol. If I kept a speed of 60 mps or lower the truck ran at its normal temperature, which is slightly just below the halfway mark on the gauge. I drove the entire distance, roughly 100 miles without the any warning lights neither coming on nor the needle ever hitting/pegging the hot mark. The truck never overheated, no water was lost, no smell of overheating, no leakage from the water pump or strange noises and once again, no warning lights!

I pulled over several times to check the fluid and every time I opened the reservoir for the radiator I noticed there was no pressure as indicated on the cap, “caution 16 lbs of pressure when hot” and the water temperature in the reservoir was extremely reasonable to the touch, you probably couldn’t even heat much less boil and egg or pasta. I thought this to be very odd? I had the radiator flushed almost to the exact day a year ago. The fan runs and cycles while idling and the temperature runs normal. In my genius state of mind I decided to experiment and pushed the truck to 75mph and the gauge would get a little closer to the hot mark, but never seemed to quite overheat. The truck temperature would drop off at a steady pace as I backed off the speed, almost matching but not quite.

I dropped the truck off an auto shop and was shocked to hear that they want to replace the radiator, water pump and thermostat for a cool $1,000. As you can imagine I was a bit shocked. This is not my first car! I have babied this truck since mile one. I have worked on cars in the past, (no master mechanic type jobs) and found it odd for all three things to be replaced. I asked if any codes came up and they did not have that information at that time. Any suggestions or comments are very much appreciated.

 

Welcome to FTE bknight44! I would replace the ECT sensor first. It may be faulty and sending an erroneous signal. This should not be too expensive to do and is worth a shot in the dark. Good luck!

 

the first thing i would do is run as fast as you can away from that auto shop. next you need to find out why you have no pressure buildup in the radiator. if the radiator cap fits good, you should build up pressure. if you have a small leak i would think you would use some coolant level. maybe the cap has a problem? KR could be right about the sensor, the other option is the sensor is right and maybe the thermostat is stuck. possibly it restricts the flow at high speed. if the truck is left idling, does it stay at a "normal" level like the thermostat is working? or does it drop low like it leaks and is partly stuck open?

 

I agree with the above. My guess would be the T stat is bad. As for that quote, radiators run $300ish from NAPA, I haven't run a quote on a water pump but I wouldn't expect much over $100 and a T-stat is around $10. Add $50 for coolant and they are just doubling the cost for their labor, that whole job would take 2 hours tops and at $90 an hour they are still a rip off.

The other thing, and the lack of pressure would not be because of this, the radiator fins could be plugged up. Look and see if there is a lot of dirt, grass or bugs in the fins blocking air flow.

I know a few years ago a new radiator cap from Ford ran around $20 FWIW. Also did you try and squeeze the upper radiator hose after this drive? It should be too hot to touch with bare hands and have plenty of pressure in it.

 

Thanks for the warm welcome! I really appreciate everyones suggestions. Where is the ETC sensor located? The car runs cool at idle no shift, cant tell if the therm is opening or not. I know the water in the overflow is nowhere near hot after a long hard push. Both top and bottom hoses are hot!

Anyhow, I started by replacing the rad cap today with a new one a realized the old cap was missing the rubber gasket, not my fault! After putting the new one i went for a 35/40 minute drive running about 75/85 mph and the needle moved slightly up toward the hot icon but not nearly as much as before, a considerable difference! About 3/16 above normal. Prior to the recent event, i could drive around 80/85/90 mph (normal driving speed for me) without the gauge ever moving from center. After getting back from the drive i slowly opened the rad cap and yet again, no pressure! Tomorrow i change the therm and possible have the radiator flushed. If this doesn't work i suppose i could swap out the rad for a new one and hope that is it. There is still no visible sign of the leaking coming from the water pump. I did not find anything blocking the radiator but i will go and power wash it in the morning, Thanks for that tip. I priced everything out and it comes to about $375.00 with new hoses as well. Any suggestion of doing a rad flush myself, good/bad idea?
once again thanks for the input!

 

bk, you live in Tx in the middle of july! that might not be that hot. i guess your saying it is different than last year. draining the radiator, putting in 2-3 gallons of fresh water, running for 15 minutes, then drain and fill with antifreeze mix. if you wish, add a cup of the "flush" during the 15 minute run. just getting the sediment off the bottom and new antifreeze in will help some... still wonder where the pressure went?

 

sounds like a plan to me, throw in a new thermostat and radiator cap and keep an eye on the level for a few days

the ect is located near the thermostat housing

if you crawl under the truck and look up at the waterpump...

if it looks like fluid has been leaking from there, replace the water pump also

 

I dont know if this would be relevent to your truck.. but i have heard of the "blades" in the water pump being worn out, which would make it have no pressure.

Also have you noticed any coolant loss?

 

The pressure should build up due to the temperature rising; the water pump has very little to do with it. It doesn't seem likely in Texas, but up here it would not be impossible to run at, say, 185 degrees and atmospheric pressure. Now you said your cap has not been holding pressure, apparently for a long time, without causing a problem. So it seems possible that your radiator is able to remove the heat put out by your engine even when the cooling system is "open".

You may not have a problem at all if, under hot, loaded, and slow conditions, your coolant is really under about 200 degrees, and you are not losing any coolant either externally or internally. But a cooling system pressure check should be inexpensive.

 

Well, other things came up and still no word from the auto shop as to what test they ran and why they charged me $78.

I will attempt to flush the rad first then replace the therm. It is funny that the rad cap had no seal for an entire year with no signs of over heating until now. Let me elaborate again, it never overheated, just got up in a zone that i did not feel comfortable.

In my search for the correct coolant to use i am a bit confused. The last place used GO5, my manual suggest E2F2-19549-AA, an online manual same year same truck suggest GO5 A.K.A. WSS-M97B51–A1.

I was wondering how can I tell if i have an internal leak. In other words will the over flow show signs of oil? As far as i can see, no indication of leaking under the water pump, although the shop said there was some indication.

I am curious if I need he bolts to the therm have a specific tightening pressure? Now that i think of it i my just go get a second opinion before getting crazy on the truck. Any suggestion on my approach or what test to run?

In any case i really appreciate the feedback. This is my first time actually doing something like this online, very cool. I will keep you informed, as i have to make a drive to IL. on the 22nd on this month.

 

The only important thing on coolant is the color, you most likely have green and need to keep it that way. There are some new coolants that can be mixed with any color that I haven't heard anything bad about and have used a few times now. If the Headgasket was leaking you should have more than enough pressure in the system and there would be either oil in the coolant or coolant in the oil and some white smoke out the tailpipe.

You said the upper hose was hot but was it firm when you squeezed it?

 

The G05 (yellow) coolant is the same as the Ford Premium Gold. It is an extended life coolant that Ford began using about the time your truck was made, but then changed back to the traditional green coolant because, I think, the G05 is more expensive and they're trying to cut costs. Supposedly the green is compatible with the yellow, but if you change, I would recommend a good flush and staying exclusively with the yellow.

My 2001 came with the green, but I changed the coolant to G05 early on when I installed a coolant heater. I believe it is easier on the water pump and, of course, lasts longer. I do not plan to go the full 100K claimed life, however.

If your coolant level is not going down and your oil looks normal, you don't have a leak. The pressure cap is there to raise the boiling point above 212. If you don't get close to that, I don't think the pressure will rise.

 

Here is the latest update. I had the rad flushed and the therm replaced, still no water loss from the pump. I took the truck out for a long drive at a higher than normal (legal) speed and everything is back in working order. All in all I paid $165.00 versus the quoted $1000.00 for an entire cooling system replacement. I am grateful for everyone’s responses. Have a great day!

 

Hooray!

glad to save someone money!

 

Hi to all, I'm new here, and glad to see this discussion about the cooling problem. I have a 2004 F150, 5.4 Lariat, 4x4 extended cab with the exact same problem.

This is what has been done: New water pump, new thermostat, new top rad. hose, flushed the rad.,new rad. cap. Does not hardly ever happen in winter (Georgia), but in summer, at 65MPH, gauge will get close to hot, back off below 65 and goes right back to normal. Can pull over when it appears to run hot, no pressure at cap, water not hot, not loosing any water. Ford dealer says this is impossible, not about to pay him any money to tell me the same thing. I don't think the truck is running hot at all, but this is very frustrating. I can understand faulty sensors, etc., but not building up pressure doesn't make sense. Several new rad. caps, so I don't think that's the problem. I'm thinking of installing a new radiator. Also have a K&N air filter, could this be a factor? Also, maybe the bottom rad. hose?

I just don't think Ford worries about customers problems like they should. Can any of you guys offer any insight now, since this thread started two years ago, maybe someone has come up with any answer.

Thanks much for your time,

Steve