Temperature question - Is this normal?

[spta97]

I took it for a longer ride last night. It reached normal operating temp and stayed there and was kicking some serious heat out of the heater vents. I sat in the spot for another minute or so and the temp stayed at normal. When i got out of the store about 45 minutes later it was bone dead cold.

However, today I started it (about 14 degrees) and let it warm for about 20 minutes, then went to the train station (5 minutes) where it just bearly got to normal temp and sat there for a few mintues with the engine running and watched the needle go down.

So this really sounds like an open thermostat? I have seen that before and the heat that comes out of the vents is minimal. Also, I wonder if the cold temps are actually causing the thermostat to sieze up? Boiling the thermostat would only truly test the theory if you were to freeze it first, then boil it.

I don't know if it makes a difference, but I've got a V8. Should I get a Motorcraft thermostat or does it make a difference?

 

[pear]

Thermostat

Sounds exactly like a thermostat to me. I'd buy a NAPA or good name after market brand, if it were me. I'd replace it while I had it out since you'd have already gone to the bother to take it out. It sounds very classic to me with the heat up then drastic cool down. Could also be that someone has put in the incorrect temp rated thermostat at some time. I'm not sure what temp rateing you need but a good parts store will have that info. If it's not that.............a new thermo is never a bad idea, but I'd have no other idea, it just sounds so classic. I'd still test the old one if for no other reason to better understand how one works. "pear"

 

[V8Exploder]

Mine does the same (always runs cool according to gauge). Even in the summer it barely creeps into the "normal" range.

Mine is the same way. Although, when it sees a little detonation.... look out !! the temp guage gets well into the end of normal.

 

[spta97]

Sounds exactly like a thermostat to me. I'd buy a NAPA or good name after market brand, if it were me. I'd replace it while I had it out since you'd have already gone to the bother to take it out. It sounds very classic to me with the heat up then drastic cool down. Could also be that someone has put in the incorrect temp rated thermostat at some time. I'm not sure what temp rateing you need but a good parts store will have that info. If it's not that.............a new thermo is never a bad idea, but I'd have no other idea, it just sounds so classic. I'd still test the old one if for no other reason to better understand how one works. "pear"

I would only take it out to replace it. However I'm not convinced I have a problem yet. The problem is when I sit in the car with the heat on after I get it up to normal temp I cannot bear it because it is so hot.

 

[pear]

Thermostat

I would only take it out to replace it. However I'm not convinced I have a problem yet. The problem is when I sit in the car with the heat on after I get it up to normal temp I cannot bear it because it is so hot.

You be the judge..........little hard to give cure when you keep changeing the story. First it reaches temp then falls back, to cold, typical "thermo" problem. Now it runs you out, because it gets to hot, so you don't think you have a problem. I'd say you have a steering problem........follow your arms back from the steering wheel and the farther you go back the closer you'll get to finding the problem !!!

 

[spta97]

You be the judge..........little hard to give cure when you keep changeing the story. First it reaches temp then falls back, to cold, typical "thermo" problem. Now it runs you out, because it gets to hot, so you don't think you have a problem. I'd say you have a steering problem........follow your arms back from the steering wheel and the farther you go back the closer you'll get to finding the problem !!!

Dude, first lose the attitude. I don't think the board is the place for it. Second, read my posts:

This morning it was pretty cold (14 degrees F) and I started my X with the remote starter and let it warm for about 15 minutes. I then got it it and drove to the train station (only about 5 minutes away). I was a little early so I waited in the truck with the heat on.

I started to watch the temp gauge go down as I sat there with the engine running. Is that normal? I was really cold but I figured the truck would get up to temp even though the engine was at idle. Should I be worried?

The engine had not reached full operating temperature. Then I ran it so it did:

I took it for a longer ride last night. It reached normal operating temp and stayed there and was kicking some serious heat out of the heater vents. I sat in the spot for another minute or so and the temp stayed at normal.

My point is when I ran it to full operating temp it didn't drop and the heat was good. That's why I'm confused and not sure if it is a problem.

 

[Mbrooks420]

When you remote start the truck is the heater on? It sounds to me like the truck just isn't heating up fully. When I run the heater with the remote start, and it's cold the truck doesn't warm up until I start driving. If I have the heater on low, or better yet off, it will warm up before I get out there. You should be able to see on the guage when the thermostat opens.

 

[SportlineXLT]

Since we're on the subject guys...My temp gauge is pretty screwy...it usually sits at or below cold, and sometimes just livens up and comes to the middle, then drops back down, fluctuates, then drops again. I was thinking thermostat, but my heat is still damn hot during all this. Maybe a faulty sensor? My MPG is pretty crappy (9-10MPG)...

 

[duckdog27]

SportlineXLT, I have the same problem with my 94 XLT, except that I have hardly any heat at all, even with the heater gauge all the way to the right. The temp gauge fluctuates on a consistent basis, from N to M with the heater off and from N to b/t L and Hot with the heater on. The other night I noticed my temp gauge was at H and I could hear my coolant bubbling. I popped the hood and discovered coolant gushing out of the overflow resevoir. I replaced my thermostat a couple of months ago and have had no previous issues with my coolant system.

 

[spta97]

When you remote start the truck is the heater on? It sounds to me like the truck just isn't heating up fully. When I run the heater with the remote start, and it's cold the truck doesn't warm up until I start driving. If I have the heater on low, or better yet off, it will warm up before I get out there. You should be able to see on the guage when the thermostat opens.

That's something I have not considered. I guess it would have a hard time getting up to temp if it is standing still in 14 degrees with the heater going. Although I do like to have a warm truck before I get in I'll try to warm it up without the heat going to see if there are different results.

How would I be able to tell when the thermostat opens? I typically will get up to just below where the picture of the thermometer is and it will stay there until I shut the truck off. However it has not been this cold since I repalced the thermostat in the summer.

Thanks for the input!

 

[spta97]

Since we're on the subject guys...My temp gauge is pretty screwy...it usually sits at or below cold, and sometimes just livens up and comes to the middle, then drops back down, fluctuates, then drops again. I was thinking thermostat, but my heat is still damn hot during all this. Maybe a faulty sensor? My MPG is pretty crappy (9-10MPG)...

This is what I would expect an open thermostat to act like. Also, could be air in the system.

 

[Mbrooks420]

The gauge will drop when the thermostat opens. If it runs for 10 minutes with the heater is on the gauge will up near the normal range.

 

[goobenet]

i just ended up replacing my radiator and t-stat. Not only was the thermostat open (and original in a 94 xlt) but the spring had gotten so bad that there was no way it'd ever close again. (Well it did, but i was using a hammer )

Now, after replacing the thermostat, my temp gauge works! It'd never gone above "N" on Normal unless it was 90 or so out and i was driving on the highway. Now it shoots up to the "O" stays there for about 5 minutes, then drops like a brick back down to "C". Either my new T-stat is dead out of the box, or the damn thing is working like it should? It has been around 0-20* the past few days up here though.

I guess those radiators too are very troublesome. Stupid people, didn't anyone tell design engineers that plastic should not really ever be coupled with metal IN FEAR OF MELTING?! Luckily the radiator only costed me $120 and a case of beer for labor.

 

[spta97]

Last night when I was coming home it was warmer (47 degrees) and my X had not reached operating temp by the time I got home from the train station. I think my t-stat is stuck open for sure now, I'll have to replace it...again

 

[pear]

Engine Temps

Thing to remember about engine warm up is this, while the vehicle is not moving heat up is not that hard to do. Friction causes heat to build in the block, and soforth, even with the thermostat fully open the water/antifreeze solution will warm up and produce heat for the heater. However once you start moving the draft of air moving through the radiator, and across the engine will quickly draw that heat off. Thus making it imposable for an engine with a fully open thermostat to produce much operating heat. This would easily explain why after stopping and waiting a few extra minutes the heat may seen to work. With a properly operating thermostat, once the needle on the gauge reaches normal it should stay there even while driving. The spring in the thermostat is designed to open and close at specific temps, to control this. If you bring a vehicle up to normal temp while setting still, the thermostat will be partly closed, to fully open. Then as you begin to move and cool/cold air moves across the block, it will close slowly to keep water/antifreeze in the block longer. The colder the ambient air temperature is the more closed the thermostat, will stay. The thermostat should be working properly, or other problems will also occur. Engines are designed to operate at a certain temp, and if they don't, fuel won't burn effectively and efficiently. Thus the thermostat plays a very important roll in the operation of the vehicle, not just the comfort from heat.

 

[pear]

Forgot to mention that a 50/50 mixture of Water to Antifreeze give the most effective solution as a coolant as well as freeze protection........."pear"

 

[Espresso]

Thought I would add fuel to this fire.
I, just this Sat replaced my WP, hoses, serp belt, rad cap & Tstat. For no reason( well I could hear the WP bearings), just to be safe & figured it needed it.
Well, now I have problems.
1st off. The heat coming from the vents is kick butt...extrememly hot. Before my temp gauge would read in the O range. Now it Barely gets to the N & shoots down below the C mark..often, even after an hour of driving.
Well last night I notice a puddle under the X. This morning come to find out it's coming from the lower intake( passenger side front).
I let it run in my driveway for about 20 minutes. The upper hose is hot like normal. Bottom hose is ICE COLD!!!!
So I shut it off & then........bubbles into the overflow tank. Nice & slow, not very aggressive like a blown head gasket. SO I slowly turn the rad cap..ICE COLD antifreeze for about the first 3 seconds. Then HOT,HOT, HOT antifreeze.
The Tstat DOES open. But it didnt until like 210 degrees( it's a 195 stat).

I knwo this sounds common. but I ahve been up for 3 days working my buut off on the house, & numberous cars. I cant think straight right now.
I'm testing the Tstat again for good measure. But i'm just going to get a new one( when my ride gets here).

So any recommemndations as to what I should check? I'm too tired right now to think.
I checked the Tstat, the heater works, ect..
The temp problems ( with the gauge) sound normal from what I have searched. But obviously not the cold hose( representive of a bad Tstat...which works??) & a leaky intake manifold gasket now.

TIA.

 

[KLUTZ]

FYI an open T stat will make your MPG go down, so if you suspect you have one change it.

Ya, from around 21 mpg down to 11 mpg. Makes you want to change it immediatly. Found that out in the fall.

 

[spta97]

Well it finally warmed up enough for me to replace the thermostat this weekend. I took out the old one (real PITA on the V8) and was about to throw in the new one but I decided to boil them both. Here were my results:

Old (AutoZone):
Rating: 192 F
Opening Temp: 188 F

New (Stant - From AutoBarn):
Rating: 195
Opening Temp: 195ish

I was using an infared thermometer on the thermostat while it was in the pan so these temp readings could be a little off. But needless to say that the AutoZone stat opened well before it should have.

This morning it was not too cold (32 or so) but my truck warmed up MUCH quicker than it has. I have not really seen an increase in gas mileage but I'm happy to see that the thermostat is working the way it should. My antifreeze mixture is a little too much on the water side so in the spring I'll have to try again (it's tough to get the right mixture when you flush the engine).

 

[Mbrooks420]

I don't think that 4 degrees would cause a huge difference. Usually the problem is that they stick open.