On my 89 F250, the temp never goes past the N of normal, I know the engine is at normal operating temp too. I am about ready to replace ALL factory gauges with those from Harbor Freight, They are 2.25 Dia white with black lettering. For $20 each I may try them out(hope that they are better than factory in accuricy) I do have the vacuum gauge installed in my E350 bus and works good!

The HF store in my area has the vac, water temp, oil temp, volts, tach and boost gauges, you all may want to check them out. Also these are all electronic sending unit gauges too(execpt the vac and boost gauges)

 

225 to 235 is too hot and is verging on overheating. You definitely have a problem but since you've replaced everything in the cooling system I don't really know what the problem is. I was thinking the wrong waterpump as well.

 

When I switched over to the serp belt drive on my 84 F250 I6 300 I still used the v-pulley water pump, never had a problem. When I did replaced that water pump I got a newer year pump for that serp belt setup, I seen no change in the impeller design. The impellers where the stright fin kind which will work either direction(universal water pump?)

One way to check for water flow and is messy AND ABOVE ALL make sure the engine is cold!! Pull the tstat out and rehook up the hose, disconnect the upper radiator hose from radiator and move it so the out flowing water don't cause further problems, turn on a garden hose and keep the radiator full while starting and running the engine. A proper operating pump will move quite-a-bit of water from the upper hose! On a truck we did that test on, the water pump would empty the radiator/engine block in a few seconds!

If that shows good, the only thing I can think of is a plugged radiator core. Even flushing several times may not unplug badly plugged vanes.

 

WoW... that is a real headache.....
Mine runs on the R at the highest.... Last summer it started running hot W/ AC was in use... a clutch fan fixed the problem on mine....

The best thing I ever did was replace the radiator on mine.... I never had any heat inside the cab when it was real cold until I did that, changing the thermostat did nothing. That instantedly fixed a couple of problems on mine...
hope you find the problem on yours.....

 

I'm back again, with new updates!:

I did replace the fan clutch; New Motorcraft Fan clutch
I replaced the already 3 year-old belt tensioner!!! the housing was completely crack the width of the Alumnium cast body..WTF? 3 years-old!!

To Donnor: I did replace the lighter 1-row core with the heavier 2-row
(Haven't seen where there is much difference) Could that be what is causing the problem?!!

Before I put the new rad in, I did flush it. I have also flushed the entire cooling system, with the t-stat out.

I wonder if for some reason the "NEW" not reman water pump is somehow not doing what it is suppose too??

I remember when it would shoot to "O" then "R", then drop back down, it doesn't do that anymore. Also, someone asked if there was a new radiator cooling cap installed when I did everything, yes! Everything! New cap, t-stat, water pump, rad. I also had a problem with the rad cap, and it was on a GMC, 200$ and all it was 12$ cap!! Crazy..

Thank you everyone for tips, suggestions and feedback!! I think were are close to exhausting this Post, but every reply counts!!

 

Also, I forgot to ask...

what if I completely removed the t-stat, and closed it back up completely, then ran the truck on a day that was hot and the A/C, and see whether or not the pump wasn't working..

Maybe?

IDK?

 

More updates Everyone!

After some time, I finally decided on using my Craftmans multimeter,temperature display with thermocouple, to get a better idea and eliminate other possible problems.
Since I have setup my cooling system with the Prestone flush system, I decided I would disconnect the hose clamps on the hose that I believe goes directly from the water pump to the heater core, then makes the continous loop through the cooling system. After slipping in the thermocouple and reconnecting and making sure everything was tight and no leaks, I fired the 'ol girl up!

Today's Ambient Air Temp:78 @ 11:00 am

To my amazement, I watched it climb from 98, 115, 150, 170, 186, 190. At this time, I can still hold the upper radiator hose and it's 90 degrees.
while still holding the upper rad. hose, I watched the temp creep to *>192<*, and as it hit 193, I felt the hot coolant slowly start flowing. It hit 194, and then it started dropping! it stayed between 186-190 for 5-10 mins, with no A/C. After kicking in the A/C(NORM, NOT MAX((Recycled)), it went to 192-193 and stayed there. After easing it to 2000 RPM, it moved to 196, then dropped back down to 192. I finalled decided to hit 2500, and held it there for maybe 10 mins and it did get to 198-204, but never over!!! I let it back down gently, and it rested at about 750 RPM, and then the temp stayed around 198-206, but that is because the air it was getting while parked was 120, give or take 10 degrees, since there was no fresh, cooled air for it take say about maybe like 60/40, 70/30 (Engine heat/ambient air).

Anyone disagree with where the thermocouple was in the heater hose, let me know your thoughts. I will try the upper rad hose in a few days, and get another conclusion. I think my results were satisfying. I know now there is a definite electrical problem somewhere that'seading to high resistance, since my Temp gauge was @ *L* and my digital gauge was 224 F.

I know my volt gauge in the cluster makes wide swings whenever I turn on my eletric fans, headlights, A/C blower motor


Well, I hope everyone has Been enjoying the Weekend!
Any thougths or suggestions, I'd enjoy reading them!
again, thanks for everyone who replied on the topics and your experiences!

 

If possable try driving around with the thermocouple installed, Just reving the engine doesn't heat them up as much as driving down the road. More load, more heat out of engine. Also do you have a automatic or manual tranny. Sometimes a automatic tranny thats overheating will cause the engine temp to rise too via the tranny cooler in the radiator. I seen that many times when out 4x4ing, engines overheating due to the transmission torque converter getting too hot from slipping.

How's the aftermarket temp guage hooked up? You might have a bad engine to chassis(cab) ground. That would explain alot of the wierd readings you have.

 

Back Again!

I tried out what you suggested EddieC. I had the same temp with driving around, with and without A/C. I know there is a ground problem somewhere now, after all the crazy readings.

I'm just more relieved now that I took the extra step in locating my problems without tearing down the entire cooling system!

Also EddieC, it's a standard tranny. I want to Thank everyone again for replying with suggestions, experiences, and advice.

The Internet serves many purposes, I'm just glad this Forum is Up and Running 24/7-365 for help and advice.