Munson

my 95 has an inline 6 which has recently been acting up. i noticed the other day that the coolant temp gauge was only moving a little bit up, just under the low point of the white line. It seems to be running fine so im not really sure my guess was a thermostat. any suggestions?
also i will post pictures of it soon i just put new 33" tires on it

Hooptie82

Get a meat thermometer and pin parts of the system from the outside. Digital would be the best route.

The 300 trucks like being warm, so if its running a little "off" and the gauge isn't rising, then it be a thermostat. I'd go no colder than 180, and likely just stay at the stock temp. On the up and up, the honestly take 15 minutes to replace on the 300.

I miss having a 300 sometimes, just neat motors.

Just call me Sean

iTrader: (1)

I think a 190 thermostat is what's recommended. With the engine cool, remove the radiator cap. Start the engine and look in the radiator for coolant flow. If the water immediately begins pumping the thermostat is stuck open. It should remain relatively still and increase in flow as the truck warms up.

Hooptie82

I don't know if its a trait they have, but I had two thermostats cross themselves up in the housing in my old 300.

bjafeman

I recently changed my thermostat out and had the same symptoms on my 91 I6. I was convinced that it was running ruch, but that may have been to some other issues.

To be sure things are working right, test your sensor for voltage and a change in resistance across different temperatures. If that checks out (probably will), toss in a 195 deg. thermostat. Turns out the one I got from the parts store was a 160 model, which is a little too cold for my preferences.

ymeski56

Your right. The engine runs over rich during the warm up cycle, where it continues running in until the ECT signals the PCM that coolant temp. has reached normal operation temp.(190-195f). Only then does the PCM enter closed loop function and apply a more efficient air/fuel mix based on real time sensor input. So the sooner that temp. is reached the less time engine operates in an over rich, less efficient manner. Although seldom mentioned the time spent operating in warm up cycle can have a noticeable effect on MPG. On a job I did last month that took 3 weeks, the location was only 7/10th of a mile from my home. My parts & supply source was 5/10th of a mile. I drove my truck 4-5 times each day but never long enough to reach normal operation temp.(closed loop function). I got 160 miles on a tank of gas(less than 10 miles/gal.). The tank before & after, I averaged a little over 15 mpg. Depending on pattern of driving, the effect to overall MPG will vary, but the time spent driving before closed loop function commences will always be less than optimum and the shorter the better. While experimenting with plug gap stretching & a healthy additional advancement of stock initial timing set, I was looking for a way to get into closed loop function asap, and I found a type of thermostat called a "performance balanced " thermostat. The one I purchased was made by "Mr.Gasket" and claimed optimum coolant temp. control. Anticipating increased engine temps. from the increased advancement I decided to offset that by using their 180F thermostat and that's what it gave me. In fact, that's all I could get out of it and probably the only way I could have got it to run hotter would be to set the truck on fire. So, I replaced the 180f w/ their 195f thermostat and it reached operating temp in 1/2 the time that my Motorcraft thermostat took & once it got to that temp., the needle never moved hotter or colder until I shut it off. After loading it down w/ 27 90 lb. bags of cement and towing a commercial mixer didn't budge the needle on the gauge, I replaced the coolant temp. sender. No difference. After confirming accuracy w/ an infrared thermal reader I realized that those thermostats are far superior to standard units. I e-mailed the company and suggested they change the name from "Performance balanced" to "*** kick'in" thermostat and a couple of days later I got one thanking me for purchasing their product, noteing other items in their product line that might interest me and although they appreciated my suggestion of an alternative product name,"performance balanced" was working pretty well for them. Anyway, besides paying for itself quickly and afterwards, reducing the amount of money you'll have to cough up at the gas station every week, it also significantly reduces the Catalytic converter from exposure to the residual effect of running in an over rich state. Running richer than 14.7:1 air to fuel ratio has killed more cats than curiosity ever has or ever will. Getting a little late for voting recommendations as to which candidate is the least likly to screw things up more than the other one is capable of (If the last sentence made perfect sense without rereading, your dyslexic, or you have a few vote's in presidential elections under your belt). That plus recommending use of this thermostat has a lot more potential to actually positively impact the financial status of persons in every tax bracket while improving the environment regardless of who we get stuck with for the next 4 years.

ranger2003

I bought the mr. gasket thermostat as you suggested looks like good quality, i havent installed it yet will do that tommrow. Did you use sealer or a gasket to seal it?

jcgonzal

I had that exact same problem, truck ran great but the temp gauge never moved. switched out the thermostat and solved the problem, and the heat in the cab improved. i used a high temp atv and the gasket, because my repair manual said to.

SoCal FORD by 4

As long as I've had my I6, the temp gauge has never passed the 'N' where it says normal. Not even on the hottest day in San Diego (which can be around 110). I've replaced the thermostat with a 190 or 195 and it did nothing for it. I've just assumed the gauge or the sending unit sucks.