Yes with the new T-Stat and other changes it would be hard pressed for them to match what ya had. Chinese precision aint what it should be. I would at least borrow a manual gauge ya can test the temp at the Rad with just to be sure what she is running at.

 

Yes, installation of a quality aftermarket temp gauge has been mentioned and hopefully would give a more dependable reading than the OEM gauge. To clarify, my concern is not the absolute temp indicated by the gauge (if it is within the normal range) as much as the fluctution during normal driving. I can understand temp changes when the engine is working harder as in heavy trailer towing or sitting in traffic with the a/c on in mid-summer, but I do not understand temp gauge changes when driving at a moderate speed down the interstate with the outside temp in the 60's. Concerning the thermostat, is there a preference for a reverse poppet thermostat that opens against the flow of coolant from the water pump or is a regular thermostat better? Just trying to use the correct one. Again, thank you for the helpful comments the forum members have provided.

 

I just go with a quality 'stat like a Stant.

 

I looked up the original temperature Thermostat. 192 degrees.

There is also a 195 degree thermostat, that Ford replaced the 192 degree thermostat with.

Three degrees isn't much, but it is enough to raise the reading on the gauge slightly. Do you know the temperature of the replacement thermostat? Just a thought...

I would not use Chinese parts unless I had no other alternative. I avoid them like the plague.

 

Gary - Stant is what I was looking at.

81F - Stant and Gates show their 195 degree models as "matching OEM" so your information about the 192 degree unit is more accurate. No, I do not know the temperature of the replacement thermostat as the mechanic says he put in "the same as was in there" but he does not remember "what was in there".

Any comments on the "regular" thermostat versus the "reverse poppet" thermostat?

Thanks.

 

Ya more info on this. Don't think I have ever heard of this by that name. What is it and how is it different?

 

x2. Haven't heard of it.

 

Arctic - Gates' website offers this: The reverse poppet thermostat opens against the flow of coolant from the water pump.
See this url: Print Brochure
Strange thing is the reverse poppet thermostat is less expensive than the "regular" thermostat but which is better for my application?

 

I read it and I still don't know. I would stay with what is common until someone that uses this thing comes along and sells us on it.

 

I agree - the common one. Pretty sure that's what these trucks came with as I've been installing them for years.

 

I would stick with the most comon type thermostat. OEM type.

192-195 is close enough not to cause problems, but might raise your gauge slightly.

If the original was a motorcraft thermostat, and was replaced with a gates or stant, etc...

 

Putting the VIN of my truck in FordParts.com and selecting "thermostat" returns Motorcraft part #RT-1139 which cross-references to Stant 13009 and Gates 33509 so I believe any of the three would be satisfactory. None of the three say or show that they come with a gasket. Did the thermostats that you installed come with a gasket or did you purchase the gasket separately? Concerning installation of the thermostat gasket, does the gasket go on the engine side or on the thermostat housing side of the thermostat? Should some type of sealant be applied to the other side of the thermostat (the side away from the gasket) before tightening the housing bolts? Thanks.

 

OK gentlemen, here are two (hopefully useful) items of information. Drove the truck 20 miles up the interstate yesterday (Thursday) afternoon and the temp gauge stayed slightly left of center the entire time. I was pleased and elected to "risk" driving the truck to work this morning (Friday) about 15 miles around Atlanta's I-285 (not a good place to break down). I left the house and as the engine warmed I noticed the gas gauge needle was "pegged" to the right beyond the full mark (it should have been between the full mark and 3/4 mark). The oil pressure gauge needle seemed to be in its usual position. When the engine reached operating temperature, the temp gauge needle was right of center and continued to move right until it was on the "L" in normal, almost out of the "normal range". Over the next couple of minutes, the temp gauge needle moved slowly back to the left and ended up slightly right of center where it remained under I reached my workplace. I recalled post #8 by 1986f150six about the ICVR and wondered if now that since another gauge is reading high if I could take that as an indication that the ICVR is bad. Sure would be great if I could replace the ICVR and solve the high temp gauge (and incorrect gas gauge) reading problem. Thanks for your help.

 

The ICVR is located on the backside of the instrument cluster. It is on the top and just to the left of the speedometer.

But first, try this... when the needles drift to the right as you described, take your fingers and firmly tap the top of the dash pad just above the location of the ICVR. I have done this and immediately the needles returned to the normal position. [Be careful and not damage the dash pad!!!]

By the way, I used to travel I-285. I lived in Powder Springs and worked in Marietta.

 

Sorry 1986F150six, did not mean to preach to the choir. If you lived in Powder Springs and traveled to Marietta, you completely understand my apprehension about the truck breaking down on 285.

Will try the tapping procedure when I leave my work place today.

I found a post about the voltage regulator losing ground and causing the gauges to peg with a suggested solution of cleaning the ground and cleaning the printed circuit. Is this worth a try?

A suggested test was to hook a wire from the ICVR mounting screw and ground that to the dash metal. If that solves the problem, the ground to the cluster has been lost. Is this worth trying?

Also found a recommendation to "fix the ground wire from the block to the cab". Where is the "ground wire from the block to the cab"? I could at least check and see if it is frayed or the connections are corroded.

Thanks so much for the good comments.