My temperature guage is starting to get up there staying between the m and a in normal. We went and looked in the radiator and it dont seem to have much circulation in there. It takes forever for my truck to get up to temperature to let the thermostat to open up... What could be doing this? Im hoping its just the thermostat instead of the water pump. Or is it even getting warm...

 

are you getting ANY water movement across the top of the rad with the t'stat open? if you've got the rad cap off and there's water movement, does running the rpm's up change the flow? if there's no change in flow, i'd be thinking water pump not performing up to snuff. if you're getting flow increase with increased rpm's sounds more like the t'stat staying partially closed. has the rad been cleaned? not real familiar with one that's clogged, but that's also something to consider. maybe this will help as a place to start looking.
BTW, the stock gauges in these ford trucks are pretty much useless, except for giving you a near heart attack on occasion when they ain't working right.

speedrdr

 

I know what you mean about the guages, I use to own a 1977 and they did that, wasnt sure if the 80 models were the same....I havnt tried revving up the motor to see if it gets a stronger flow...I think no matter what im going to go with a motor rad fail safe T-stat.

Whats involved in getting the radiator cleaned?

It does take about 30 to 40 minutes for the T-stat to open up when the truck is sitting at idle. Is that normal?

 

With temps in the 40's, yes.
Diesels do not make much heat while idling.

 

I second that, especially the 1000lb cast iron variaty of diesels.

 

I just installed a new water temp sensor so the gauge works now. Now when I'm driving, the temp gauge is on the L in normal or to the line to the right of normal.

Is it running hot? Maybe hot t-stat in there?

 

It should not be over to the l but I have never trusted the factory guages, and have always installed mechanical guages. A point and shoot pyrometer is a cheap investment I have bought several at harbor freight and they are pretty accurate and only about 28 dollars, you can check your tranny, rearend, and find hotspots in your radiator to check for flow, also wheelbearings etc.

 

I'm going to drive out to my folk's place again to help wrench on my stepdad's Chevy. I'll pull the radiator cap and throw a thermometer in there to see how hot it's getting. There's a brand new water pump on this thing. Would a hot thermostat cause it to run hot? The temp light has never come on, but I'm not sure that it even works. The oil seems fine.

The heat gets so hot, I have to turn it down midway between hot and cold. The dash where you adjust the heat feels really hot too.

 

The heater getting hot is normal and at least tells you the water is circulating. Is your fan coming on assuming it is working properly it will come on around 205 and it doesn't care what your guage says. A stuck thermostat will cause it to heat and they have been known to stick partial open not neccesarily open or closed. If it was me I would hook up a mechanical guage for piece of mind.

 

It's a standard transmission w/ a clutch fan and I'm not sure if it comes on or not. It always spins. Do you think it's worth while to install a new thermostat?

 

Anything is worthwile instead of burning the motor up, if your fan comes on you will know it you will think an airplane is taking off. If you decide to install a new thermostat I would get an oem from ford or international the aftermarkets sold at parts houses have a terrible track record on our diesels. Personally before I installed a thermostat I would install a mechanical guage for real temps, if you put a new thermostat and your guage still reads the same how do you know if you accomplished anything or not you will always be looking at that guage and wandering if it is hot or not.

 

Are you talking about an electric fan? I'll have to check on the fan. I figured the thermometer in the radiator cap would tell me if it's really that hot or not. I'll get a new t-stat from Ford instead of a parts store. Thanks for the heads up on the t-stats.

The stock oil pressure gauge is weird too. Are there gauge pods available for these trucks? Pillar gauges?

 

A thermometer will tell you but say it is 195 on your thermometer and your guage is reading on the high side, now next month your actual temp goes to 250 and your guage that you know is not accurate barely moves how are you going to know what is actually happening, I am sorta **** about real guages as I depend on my rigs and travel where a breakdown can get serious.
The pillars for 86 models as far as I know are no longer available, but I understand that the 88 up works with just a little modification. I have not done this I just have a 3 guage cluster on mine and am not satified with the way it looks and I have no place for a boost guage and thermometer that I want, so I am thinking about fabbing something up.
The fan I'm talking about is the stock fan,it is controlled by the temp of the air flowing thru the radiator, These trucks probably have the best cooling system ever put in a pickup and the fan is comparable with much larger trucks when your fan clutch locks up it is very audible.
I'm thinking your rig is not really running that hot especially if your fan is not coming on, but if you have never heard it it may not be working either, every thing wears out eventually.

 

also if your going to check the temp of the coolant the fill neck is not a good place to do it the bottom of the radiator is.with the point and shoot thermometer you can shoot it at the bottom of the radiator and the top the top should be cooler if not you have a water pump or thermostat issue,putting a new thermostat is a cheap way to start and like startmilt said only put in an oem thermostat.i didnt know any better when i did mine but luckily i havent had issues.being your in ohio with your temps just driving it SHOULD cool it down and if its getting that hot your fan clutch should be locked if its not your gauge is messed up or your fan clutch is.

 

There's no electric fan in there. I just looked. I have the radiator and another radiator looking deal in front of it. Then there's the clutch fan. Why would the clutch fan be really loud? The temps gauge is pointing where I said it is when I'm driving 55mph down the road in the cold here in Idaho. I'll have to pick up one of those point and shoot thermo deals.