Will higher thermostat help this......

rseifert

Founding Member
Mar 13, 2001
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Lung Gyland, NY
My stock '92 has always run cool. (I dont have a real temp guage, this is based off the stock in the guage cluster). It always kinda bothered me, but now w/ the ridiculous price of fuel it kills me. 95% of my driving is very local and I am getting horrible gas mileage because most of the time my engine is running, it is cold. I feel like if my car would warm up faster or at all for that matter, it would run a little more efficiently. It takes longer than any other car I have driven to warm up. And when it is warm, it hardly passes the first line on the stock guage. It is the stock stat and I know it isnt stuck open because I can see the needle go up and down slightly as it opens and closes. There is also very little difference between winter and summer (which is weird because that can be a difference of 75 degrees!) I took out my hood insulation a while back due to a fire, would that effect it? I tried blocking the condensor w/ cardboard, but that did nothing. What can I do? Should I not worry about it? Any suggestions much appreciated.
 
The stock gauge is relatively hysteretic. It is simply too hard to guess at what is going on. FWIW, my stocker would read about 35* too cool.

The stat should regulate things, the fuel trim should be halfway decent if your O2's work, and if you say it has a stock stat, it should be running as warm as it can.

If you wanted to replace the stat for the sake of doing so, that is a good idea. Otherwise, though we are all sick of hearing it, the stock gauge is simply (and largely by design) not accurate enough to interpolate.

MHO.

Good luck.
 
Yeah, the stock gauge is pretty sketchy.

You may be able to find a low cost temperature gauge and sending unit at a local parts store, but I don't know what the quality would be like.

When the fuel economy is bad, the fuel injectors seem to usually be the cause. It may be worth pulling the codes. Searching through old posts from jrichker will reveal some options for pulling the codes.

If the stock stat is right then that is way too cold. But, the stock gauges aren't reliable enough, and readings need to be verified.

jason
 
Eh.. poor gas mileage can be a number of things from o2 sensors, to exhaust leaks, to spark plugs, injectors, the list goes on.

To answer your original question, I would say yes, a higher thermostat should help raise your temperature, although I'm a bit hesitant to recommend that based on your still having the stock gauge. It's so hard to know what's really going on.. my 88's gauges were crazy.. oil pressure was normal, but always read high, coolant was normal but read low, and voltmeter needle was always pegged when the voltage was normal. All it takes is one douche-bag like me to incorrectly place the needles after a cluster face swap, or to swap a cluster from someone elses car (with unknown needle removal/installation history,) to screw it up.

FWIW, as you know, Mustangs aren't popular due to their great gas mileage ratings, so the fact that you don't get that great MPG + your low temp. readings *may* be unrelated.
 
I would buy an aftermarket guage first. Even if it reads the same its still a good investment. You can also stop by a shop and have them point a temp gun on the car in various places and compare his readings to your guage. I'v had that done a few times and they never charged me anything to do it as it only takes about 2 minutes if that. When the car is warmed up (in your case, at the first line on your guage) does your heater blow hot air. If the car is not heating up past the first line you won't get but cool-warm air blowing out the heater. Warm the car up and warm up your DD if you have one or warm up a friend/relatives car and compare the air coming out the heater. Remember, this wont tell you how hot/cold the engine is running but will let you know if your guage is off that terribly bad. Good luck.
 
I do get warm air out of the vent eventually, but it is not "hot" by any means. Especially compared to other cars I've driven. I get about 15 mpg city with a stock 125,000 mi motor and headers. I actually can get up to 25 mpg on the highway though, so that's why I thought the bad city mpg could have something to do w/ the fact that most of the time I'm behind the wheel of my car, it's cold. (I only work about 10 to 15 minutes from home). So really, i'm more concerened with the slowness at which my engine warms up. I guess the thermostat won't really effect that, huh? Anything else I can do?
Can you guys recomend a decently priced and effective temp guage?

Thanks for the replies!
 
That stat might not be stuck open, but I wonder if it isnt able to close all the way.

15/25 MPH is pretty good, especially since you have such a short drive to work (that is lots of open loop time, relative to total drive time).

Autometer, VDO, Stewart, et al make great gauges. Even the stuff at the parts store will be tons better than the stock gauge.

Good luck.