I put in a Auto meter electrical type water temp gauge because i was seeing fluxuation in the stock dash gauge. it appears that the stock gauge was really seeing something. Correct me if iam wrong but the stock thermostat is 195 right? Anyhoe the the autometer gauge is fluxuating between 180 to approx 200. I just put in a new radiator because the old one was leaking a week ago that was for a 7.5L for my 347 with no change. Its acting like a sticky thermostat, but this is the second ford thermostat and it did the same exact thing. Am i overly concerned about this or should i try another thermostat again?

 

Just doing what comes naturally!!!

 

Yup, perfectly normal. Once the radiator has gotten some heat in it the swings should settle down, usually after 30 minutes or so, but even if it doesn't 180-200 is nothing to be worried about. Keep in mind that the thermostat is on the output side so it's going to make sure the radiator is seeing well regulated temps, not necessarily the engine. The engine gets nice and warm. Then the thermostat opens and lets nice slug of cold coolant shoot around the engine and slams shut again. This cycle repeats until the coolant in the radiator is closer to the engine side.

Really the news here is the variability in the stock gauges. Some are damped a lot more than others. The gauge in my '95 would swing all over the place while the one on my '96 I have now doesn't let on to what's really happening. I have a ScanGaugeII so I can see the real numbers go by and it gives me the about the same show as you are getting, 175-205 and back for the first twenty minutes or so.

 

*dupe* grrrr! is the board flaky for anyone else? it takes forever to load sometimes.

 

it occationally shuts down explorer

 

i had the same problem...my new radiator is so efficient that the t-stat would keep opening and closing, the gauge was all over the place.

I drilled a small hole in the top of the t-stat and it solved that problem, and doesnt affect warm up time.

 

Hello Shuttlevalve,how are you today ?
just wondering ,where is the Temperature Sending Unit on your vehicle.
I can not find the one on my 1988 FORD f350 ,460 engine, as my guage is not functioning.
thank you

 

I swapped my thermostat. I think I'm running a 180. Well of course my gauge was wrong before this so now I'm trying to figure out whether or not to swap the sending unit or leave as is.

I thought the cluster was bad, cause the temp gauge and oil pressure didn't read right and I grounded the gauges and they didn't peg. Swapped the oil pressure sending unit and that does like it should now. If temp gauge doesn't act right after swap I have a spare cluster looking me in the face right now haha.

My truck's cruising temp isn't even at the N of Normal. Idle temp is at the N. Starting to overheat is at the R I'd say, as I started to boil coolant one time when I got stuck in mud with a bad fan clutch.

 

mine is in the intake manifold forward left side.

 

I run a 180F w/ a new extra capacity aluminum radiator. Little if any flux after reaching op temp even w/ a/c on. If a thermostat has been exposed to an overheat condition, the gauge will wander afterwards as a result. The replacement radiator was as a result of a thermostat suddenly failing closed. Luck the head gasket hung in there! If I wasn't running at 16 BTDC, I might have stayed w/ a 195F. If you know your 195F thermostat is in good shape, a product called "Water Wetter" will take all the wandering out of your gauge. I'd start with 1/2 bottle especially if your running a "distilled water/ antifreeze, as a full bottle may drop your temp by up to 12 degrees. This can get a little touchy, because you need 182-185 to enter ECU closed loop function, where over rich cold start/warm up ends & ECU controlled fuel trim begins! I use a Laser thermal reader aimed at my thermostat housing to get the straight temp poop, along w/ my code reader to make sure the ECT is getting the temp it needs to initiate closed loop function.