I'm looking into getting a high-performance thermostat (is there such a thing?) to lower the temp in my '99 4.6L Supercab.

1) What should the temp be? 180? 190?

2) What company is the best? I was suggested Mr. Gasket but I am having a hard time finding one specifically for my engine. Suggestions?

I'm open to just about anything. If you need more specs, go ahead and ask

Thanks

 

A low temp thermostat is a gimmick to force the car into cold-start enrichment mode all the time.

Just stay with stock.

Steve

 

Go to the dealer and ask for a Lightning thermostat. I cannot remember but I think that they are 180 or 185°. i have one in the truck now. I didn't install it for performance but because I was chasing an over heating problem and it was a temp solution. This post just reminded me that I have to take it out. :o

Regards

Jean Marc Chartier

 

yes, keep the stock. Try to understand the system like this: THe cooling system is not to cool off the engine, but rather keep it at operating temperature.

 

Thanks for the feedback. What do you guys suggest?

Its difficult for me to pinpoint whether its something I should worry about or not... my instrument panel is fubar'd as a result of some DIY panel details/graphics where I did not pull the needles off correctly. I've corrected mentally for the shift (it reads hot when its really in the middle, so I believe; when its cold the needle reads in the middle) but I'm still worried about heat, especially with my driving.

I'm only paranoid about this because of an incident with my first car where I was doing 100 on a slight incline and didn't realize it until I had to limp off the freeway @ 30 mph. I just get nervous when I can feel the heat pouring from the sides. Should I even worry about this?

 

Get a stand alone water temp gauge. It will have its own probe which will need to be installed. (Don't take out the original sending unit as the computer may also be using it)

 

Pull the needles that are not calibrated correctly off and try the following.
With the key off press the odometer reset button and hold it. Turn the key to on without starting the engine. When the odometer spells test release the reset button. Now press the button and release it till the odometer spells guage. This will cycle the needles from low to high readings. That is why you should remove the needles. Now that they are cycled press on the needles that you removed to the low seetings.
BTW this should be done with a cold engine. Now press and release the odo reset button till it reads guages again and watch the needles sweep. They should go from the low to high readings. Adjust them as required.

JMC

 

A little additional info on the excellant idea JMC wrote,
When you have the cluster in test mode, and scroll thru the readings. The deGC read out is the display of engine temperature in Degress C input from the cylinder head temperature sesnsor.

The readings are as follows:

49 c "C" mark
60 c Normal band start
120 c Normal band end
-40 c No SCP message for 5 seconds

On my truck with it at idle and no A/C running and temp stabilized my reading is about 95 c.

And test can run with the engine running also. Just do as JMC stated, only go right to start instead of run as Jean said, and hold the button until it reads test, then step thru the readings, it will give you tach readings and other neat stuff and useless stuff as well

Good luck!

Gene

 

If you want a good quality thermostat go to Autozone and buy a MOTORAD thermostat.

These are made so that if they fail they fail in the open position, not closed.
That way your engine will not overheat.

 

it is ok to run a 180 therm, it will lower your temps about 10, if you plan on doing towing or climb alot of hills or offroading

 

Someone correct me it I'm wrong but the stock thermostat for the 5.4L is 180 to 190 degees F. That means it starts to open at around 180 degrees + or - a few degrees and is full open at 190 + or - a few degrees. These aren't the most accurate things in world. The point is you want it to be and remain in the full open position.

I hear of all the trucks in the forum running HOT. Can someone define what HOT is. The 5.4L can run up to 220 degrees F and not be running HOT.

 

The stock thermostat is a 195°. My cylinder head temp varries between 85-89°C. That is 185° to 192°F.


JMC

 

That's pretty hot to me......

I've got the stock setup, but have an Autometer Water (and Trans) temp gauge setup. I take the water temp off of the inlet hose to the heater core. (so it's gone all the way through the engine)

The most my water temp has gone to has been 210* and that was towing a #4500 travel trailer up a good 6% or so grade in the Cascades on I-90 here in Wa State. It was in June and the outside temps were in the mid 90's.

I was in second gear, going about 50 mph and pulling around 3500 rpms. I only had my foot into the go pedal about half way. Had plenty more to give, I just did not need to push it that hard.... Oh, I had the A/C cranked as well....

At that point, it would not have made any difference if I had a 180* or even a 160* 'stat...... The only thing that would keep it cooler in that specific situation would be a "better" rad...... I've already got the two core rad and for everyday running around, my temps are barely over 190*. When it's really cold outside, my temp will stay just above the 180* mark.....

Oh, where does the stock temp gauge read???? Right where it always does.... Never moves or gives you any indication of temp changes.... It reads "normal" when the other gauge is only at 150*..........

Mitch

 

MitchF150

I think you just proved my point. If you only had water in the Rad it would boil at 212 F. With antifreeze and under pressure the boiling point goes up.

Mitch is running 210 F and no sign of running hot. If you're only getting 180 F in cold weather, I would say you need to shutoff some of the air in front of the RAd during cold weather. Your thermostat is opening and closing because of the cold coolant. Thats the nice thing about electric fans. you can shut them off when you don't need them. Sounds like Mitch's 2 core Rad is doing the job for him in the hot summer month.

I hope this helps.