Temp gauge barely moves on my truck

[kevm14]

I had the same problem until today I took the thermostat housing off and found the thermostat was not seated all the way there are two small tabs that keep it from going into the block and loosing its seal against the housing they needed to be spread out a little bit also the housing of the actual thermostat was just about blocking the hole for the heater core. I reassembled and now it’s nice and toasty.

Can you elaborate on this at all? I recently replaced my WP and stat and the engine is overcooled, running about 170° on the highway. I am thinking that either the stat isn't fully seated or the inside of the thermostat housing is corroded enough to keep the gasket on the stat from correctly sealing. Does this sound likely? Seems to me just about the only thing that could keep an engine from warming up is a fault in and/or around the thermostat. I did use a Motorcraft stat so it shouldn't be a case of improper fitment. It did lock in when I twisted it.

Maybe I'll try bending those tabs and making sure the stat is fully seated in the housing before buying one of these for $64:
http://info.rockauto.com/getimage/g...http://info.rockauto.com/Motorcraft/rh-35.gif

 

[Danger-Ranger96]

mine worked for a while, then it stopped getting above C, so i figured it was the thermostat, Sure enough i changed it and flushed the coolant and my temp now goes back to mid gauge when its up to op temp. I found after changing it, being up here in Canada, the heater works alot better as well now that its running normal.

 

[VaGent]

For what it is worth, I did some investigateing Ford gauges & found out that Ford has never admitted to having lousy reading gauges. Ezpecially the oil pressure gauge. Back in the late 80s Ford was having lots of problems with them & would never admit the gauges they were using were not very good. This information came to me by way of a cousin who worked for Ford as an engineer. I myself have not had a problem with the oil pressure gauge & but I am very familiar with the temperature gauge problem. After doing a lot of testing I discovered my gauge was not working right either. I changed out 9 different ones before I found one that read what the water temperature actually was & this was verified by using a Snap-On temperature tester. The quickest way to fix this problem is to get a after market gauge & install it. I like Sun gauges myself but any good named brand gauge will do IMO. I was running a 195 degree thermostate & installed a new sending unit & my gauge still read COLD all the time. Now that I have finally found one that reads correctly I am pleased. I LOVE FORD TRUCKS but some of their gauges really suck.

 

[kevm14]

I thought the oil pressure guage was just a dummy gauge anyway, akin to a light.

Using my scantool I can at least verify that the guage and the ECT sensor corraborate each other. Right now I'm trying to figure out why my brand new Motorcraft thermostat yields 170 degree coolant temps on the highway. I personally verified it opening at 190 in a pot of water.

 

[cocoasranger]

In the Haynes manual there is a schematic which clearly shows that the stock oil guage assembly consists of a sensor which is just and on/off switch, plus a resister so there is a reading of roughly half dial (the exact needle position depends on the condition of the electrical system at the time, so you get slightly different readings from day to day).

 

[kevm14]

That makes sense. Too bad they did it that way though. Is there a real variable resistance sending unit available?

I tried a NAPA thermostat just in case I had a bad out of box Motorcraft thermostat and it is behaving the same way. However, I noticed that the way the reported coolant temp ramps up then tapers off looks A LOT like the stat opening. If I added ~25° to the values I'm seeing on my scantool, I guess everything would be working correctly, so I am finally just going to replace the ECT sensor like I should have already. Hopefully that works, and allows the ECM to stay in closed loop on the highway above 65mph. I also expect some EGR operation when the ECM reads the engine as "fully warmed up." It's probably fully warmed up now, running at 195°. Stupid Ford sensors.

 

[RangerHunter66]

i just got a 1994 Ford Ranger XLT 4.0L 4x4 so i am new to the "Ranger Scene" but i noticed that my temp guage isnt movin very far either and i saw that installing a manual guage lets you keep a closer eye on the temp but can any one help me with the install?? like i said i am new so idk the ins and outs of my ranger yet....

 

[kool_ranger]

Went to napa today, got the listing OE thermostat which is 195, installed it with a new o-ring, flushed my heater core and added all new coolant and she got heat like crazy now and the temp stays right around the middle or just below, which i am guessing it should be at. I will put the 180 back in for the summer but for now, 195 all the way lol

 

[MAKG]

There is no advantage whatsoever to a 180 deg thermostat. Just leave the 195 deg in.

For the tangental oil pressure gauge question, yes there is a variable-rate sender (among others, it was used in 1983-87 RBVs, though the gauge itself is also not the same), but it's still electrical and still uncalibrated. If you can't say you have 40-60 PSI pressure with a fully warmed engine at 2000 RPM, the oil pressure guage -- whether real or fake -- is not useful.

 

[kool_ranger]

There is no advantage whatsoever to a 180 deg thermostat. Just leave the 195 deg in.

For the tangental oil pressure gauge question, yes there is a variable-rate sender (among others, it was used in 1983-87 RBVs, though the gauge itself is also not the same), but it's still electrical and still uncalibrated. If you can't say you have 40-60 PSI pressure with a fully warmed engine at 2000 RPM, the oil pressure guage -- whether real or fake -- is not useful.

Sounds good but wouldn't it get warm real fast idling in city driving?

 

[MAKG]

A lower thermostat does nothing to cooling capacity. A wide open thermostat is a wide open thermostat and if your radiator can't keep up, it really doesn't matter if it opened 5 seconds earlier.

If you're overheating at idle, your fan clutch isn't working.

 

[kool_ranger]

another thing happended to, some antifreeze made it's way into the cab, i think it's when i pulled the inlet hose off at the heater core while the truck was running lol, i ran the fan and it smelled like coolant but it seems to have gone away now..... and there was a film on the windshield it looked like and i wiped it off probably due to the coolant. I noticed a little bit inside the truck on the firewall but very little and was one small wet spot. I am guesing a little got in the truck when it sprayed everywhere... how long before it goes away?