I need an opinion here and do you think the radiator is working right. I was concerned that it might be clogged even though it looks clear and clean from the cap hole.. Perhaps the gauge or temp sending unit is bad..

Ok so My 88 e150 w/302 Was running hot sometimes, cool others, according to the them gauge. Between the O and R on the (NORMAL). Then it started staying mostly between the between the R and M. Then finally almost at the L when sitting at alight after being in overdrive a mile or so and coming to a stop. BUT occasionally it would go back to between the O and R.

I went to NAPA and explained what was happening. The older counter guy as well as a mechanic there said it was the fan clutch not engaging properly. I replaced the fan clutch and now I do hear it kick in at carious times. But that did not stop the gauge from what I described above.. So I replaced the thermostat. All they had was a 195F.

After replacing the Stat, filling it with coolant, beading the system of air, sitting in the yard the gauge needle was higher then before. It now stays between the M and A when idling, without having driven it. Now when driving and coming to a stop, the needle will move up and touch the L.

Here is the gauge at idle


Here is the gauge after driving a mile or so in OD and coming to a stop


I drove up the interstate in OD for 5 miles and the needle stayed between the M and A like the first pic.. I drove back down the interstate where I had to climb a long hill with a special truck lane for slow trucks and the gauge still stayed between the M and A.. So under a load at 70mph the temp is not rising any more then riding around town.

I borrowed a laser thermometer and did some readings With the gauge needle pointing almost on the A and here is what i got in several places.


When the needle was touching the L, the temp only went up to 201F.
Using the temp gun I was about a 8" to 10" away from the areas I checked. I noticed iF I got the gun as close as possible, about 2 to 3 inches away and very hot on the hands, that it read about 2 degrees hotter. If I moved it back 14" to 16", the temp read about 2 degrees cooler then the recorded readings.

Is a 70F difference between the top and bottom of the radiator normal? It was about 70F outside today..
Thanks

 

Have you noticed that gas gauges moving too? I had a bad panel voltage regulator that looked like this. The gas, oil, and temp needles would creep up sometimes, other times normal. I noticed that when the heater fan was turned on high that the readings got lower.
Unfortunately, I had changed out the usual parts before I figured it all out.
The temp readings look normal, perhaps change the temp sensor for the gauge, it is easy and cheap.
jim

 

Thanks Jim.. I am going to try the temp sender first.. Interesting about the panel voltage regulator. The Oil gauge is pretty steady starting at the A when the engine is cold and between the O and R once the engine is hot. The Alt gauge needle jumps way up just as soon as you let go of the key on start up, then drops right back to just a little above the center line..
Just before I bought the van the gas tank, filter, sending unit/pump was changed out. I would be surprised if they used a Motorcraft replacement. the fuel gauge does tend to wander a little but is not affected by turning the headlights on along with the blower fan on high.
The temp gauge was all over the place today.. This morning it was lightly raining and it never went past the R.. After it stopped raining and the temp was about 10 degrees cooler then yesterday, the needle pretty much strayed between the R and M, straight up... Later this evening when it was a bit cooler outside, it went back up to around the A...
When i first used the laser temp gun, the thermostat had not opened and the upper hose was still cool.. I checked the temp with the laser gun every few minutes until the thermostat opened and the hose started getting hot.. The temp read 196F at that time and the needle was on the M... That brings up an interesting thought... How could it run for miles and stay in the O/R range if the day before the needle was at the M before the stat opened!
Now this is all going off the readings from a AZ borrowed laser thermometer... Even it the calibration was off on the thermometer the needle was covering a wide range of swing for just a 5 degrees difference in temps.. I was not able to get a temp reading when the needle was between the O and R because yesterday after the stat opened, it never went below the M

You know the AC is bypassed and I don.t have a tensinor on it right now.. The belt isn't as tight as I would like it to be but I don't believe it is slipping because with the new fan clutch working, I can hear the fan roaring and no squealing.. If it is not slipping when the fan is in gauged fully then it shouldn't be slipping when not engauged.

 

OH I do have a spare instrument cluster that should have a panel voltage regulator. I am not sure what year it came out of,, but somewhere around the mid to late 80's.. I do remember the van had a 4 speed manual transmission in it...

 

I had this problem and found that the "pin" type ground connector at the battery (-) to chassis was defective/not good. I replaced the supplemental ground cable and the problem was taken care of. Also see if your "speed" selector on the heater/A/C doesn't make the gauge read high when you select any speed other than "low". That would indicate an insufficient ground for the blower motor.

 

Exactly, supertwin. When my gauge would peg hot, the first action was to switch the heater to high speed to help cool the engine. That was enough electrical load to lower the dash voltage and the temp needle would drop. I chased overheat problems for a while before connecting the dots to a bad panel voltage regulator and grounding problems. Now, I look for that first.
jim

 

did you change the rad cap? My ranger was running hot and I could not figure it out thought it was the fan also. Turns out I had rad cap that would not hold pressure yet would not boil over either. My 72 400 ford had the same issue, thought it was a stuck tstat, also turned out to be a bad cap.

 

Yes I just replaced the cap last week... I installed a mechanical gauge to eliminate errors with the dash gauge.. will get back to the dash gauge once I figure out what is going on.. The van sat for some years and so i need to go through and clean all the grounds. I also want to take the instrument cluster out to lube the odometer cable and change the bulbs... hopefully the cluster ground is in there!

I kinda got this thread going on in two different threads.. Not sure how to get them back to one..
But here is the one where I installed a mechanical gauge temporarily and have been discussing the problem there..
Thanks for your help and advice..
https://www.ford-trucks.com/forums/1...-firewall.html

 

This could be the voltage regulator that always goes bad in these van clusters, have you noticed the gas and oil pressure gauge go up to?


In my '91 Diesel club wagon, this is really bad if I use the heater, the dash gets hot, and if I sit at a long red light or whatever, I'd loose all the gauges, they would all max out. I have real gauges so I don't worry. I don't bother with it as the van is stored for winter, so I don't use the heater much. It will happen every now and then on really hot days in summer.

 

The rest of the gauges seem to be working properly, I think..
The ampmeter will spike up just after releasing the ignition from the start position. Right after the spike, it settles down to just to the left of above the center line
The oil pressure gauge starts off (NORMAL) with the needle pointing between the M and A. As the engine warms up to temp, the needle drops down to between the O and R at idle.
The fuel gauge is not as stable as I would like for it to be but the fuel sending unit was changed out before I bought the van.
None of them continue to rise on the scale and turning on the blower motor doesn't seem to affect the gauges. The blower motor does quit after running it for a while on high speed. After a few moments it will come back on.. IF you set the blower to medium speed, it runs much longer before cutting off. On low speed it will continue to run..

I do know there was a problem within the AC system in the past. When I got the van the AC compressor was bypassed due to a bad clutch bearing. While changing the bearing I found the clutch coil was burnt up. There is also a pressure switch on the (dryer or accumulator) and the male part of the plug going into the socket appears to have gotten hoe at one time..
But perhaps that is not elated to the temp gauge..