92 F150 2x4 I6
I just installed another T Stat to try and get my heat range up. The gauge is just touching the outside of the normal range. (cold side) I just did a tune up a couple of days ago. Pulled the plugs which were pretty worn. "Great" I said. Theres where my gas mileage is going. Starts up fine,idles mint.plenty of power. Gas mileage still in the crapper. Soooooooo I went and got a new Coolant temp sensor. BINGO! Gas gauge hardly moves now. (have not driven it long enough to check actual Mileage yet) Trust me it was so bad I started looking for leaks.

My next concern is if my temp guage is falty, or temp switch is no good. (I know Im taking the long way around for a simple question) The more info. the better,right? According to what I have read. the temp switch is supposed to be above the starter. Some where in that area. Well I can't find it. Either my eyes are going bad or to many brews before I started looking for it. Also does anybody else have problems getting the cooling system full? That upper rad. hose is pretty high above the motor. So to answer my question. Am I blind or drunk?

TIA,Frank

 

The water temp gauge sits at the very top rear of the block on the pass. side. In my van it's right there with the doghouse removed... but in a truck it's WAY up in a hard to reach spot. It's pretty small and doesn't stick out like the typical oil pressure sender, so best way to find it may be to follow the wire.

The sender could be bad, or it could simply be a bad/ lose connection at the sender. My gauges were all reading erratically till I discovered the old wiring was corroded. Patched in new wiring from the firewall to the senders and now the gauges read as they should.

 

I don't think it's the sender as I'm on my second 195 thermostat as well with the same situation you describe, I'm lucky if my temp gauge makes it to the N in normal. I genuinelly believe the truck just runs too cool as my heater just gets kinda warm. But I'll get my digital multimeter with a temp probe out as well as a 150 and 200 degree tempstick and see.

 

The temp gauge not getting to the N is normal, even if you have a 195 t-stat.

 

Sorry I don't get what you're trying to say.


Anyway I got the two tempsticks out that I had on hand an 150 and a 225. With the needle on the "N" the 150 tempstick will melt on the t stat housing the 225 does not. For what that's worth. Monday I'll borrow a 200 degree tempstick from work. I'll get the multimeter out later.

 

My temp guage used to run higher than where it is right now. The last t stat did not give me much heat. This one seems alot better as far as heat goes. For a lousy eight bucks I just assume change the temp switch and then take it from there. does the wire go around the back of the motor, or thru the top which i could not find when I looked. One thing I forgot to mention. I just put a new rad in about two months ago. Only because it looked pretty shabby. I also think that little bypass hose does not allow you to fill coolant all the way. What i did was clamp it and the coolant droped in the rad. enough to get atleast another quart in. maybe more.

 

IIRC, the inline motors suffer from overcooling in these trucks. In the winter, I'd cover half my radiator up with cardboard to keep the engine warm enough (and me!). Perhaps it's because the motors were intended for heavy duty use and are just loafing in our vehicles.

 

I think I am going to try and block off the bypass hose that comes from one of the heater lines. It seems like it lets to much flow through the system,which in turn does not let the t stat to function the way it is supposed to. Any thoughts on this idea?
(might be better than cardboard) Not to say I haven't done that on other cars where I know stat was not fully closing.

 

Are you using the same brand of t-stat every time? I had a problem on my old car where the Advance Auto t-stats were garbage and never worked. Replaced it with an OEM part, and it was rock solid.

 

Nope different eveytime. Learned that lesson long ago. Good thought tho.

 

Never thought of the bypass hose. I'll look at that.

 

Don't bother pinched it off for 5 min. didn't do squat. If anything it ran a little cooler.
How about the fan clutch not unlocking? Grasping at straws here. Got an extra piece of cardboard?

 

I didn't think these things had fan clutches- which could be a major source of your problem. My 88 had a big steel 4-blade fan right on the water pump. You could put on a thermal fan clutch and a modern flex-fan. I know Summit sells Flex-A-Lite brand stuff that's OEM bolt-on and costs about $60. AutoZone/AdvanceAuto probably has them too.

 

Temp switch tomorrow. I have to know if guage is reading right first. Its just not cold enough to judge it just from the heat output. Will post with results as soon as I know for sure. Thanks all.

 

He's trying to say that these guages are pathetically inaccurate and just because it's reading cold doesn't mean the engine is cold.