Ok, i just installed some mechanical gauges in my 93 f150 and im wondering what kinda of coolant temps i should see. Right now it hits 210 normally and up to 220 on a longer hill. But i also live in TX where its 100 degrees already and A/C is on full blast. and it has a 195 T-stat.

I also have a friend with a small block chevy and his temp sits around 200 all the time. So for mine to hit 220 doesnt seem that bad.

Are these kinds of temps normal? I know these like to run hot, but i just want to make sure.

Thanks for any help!

 

That's a little high. They're not supposed to run hot; I've never heard that before. I have a 195 T-stat in mine, and it sits at 195. I do run an electric fan; I can't remember the CFM but it's relatively low (the fan is only 2 inches thick). If it's really hot outside and I'm stuck in traffic for 10 minutes, it can creep to 205. But under normal driving conditions, it stays at 195. I'm in Texas too.

If your engine is sitting at 210 and hits 220 fairly often, that's outside of my comfort zone. Try flushing the entire cooling system. Make sure your fan belt is tight. I have heard cases where the water pump impeller rusts and small pieces brake off such that it turns less volume; if flushing the cooling system doesn't work and the coolant is full of rust, a new water pump is cheap.

 

Hey fmc400, thanks for the reply. I used to run an electric fan too, the motor burned up last friday and im trying to get it warrantied. Anyways, the weird thing is that it hits 220 on the highway. it comes down to 210-205 at idle.

As for the cooling system, iv never changed the pump, but it does have a new fan clutch that only slightly engages at 215. Nothing near what it can engage on a cold start. The system is full of rust and the water was brown. The over flow used to have about 1/2 inch of much in the bottom i rinsed out.

So im guessing it might be time for a new water pump? Its got 117000 miles on it.
But what throws me off is that it keeps it between 210 and 220 like that were its supposed to run.

Thanks for the info, i need to get this figured out. I use the truck for work and need it in top condition.

 

Sorry,

I dont know why my PC keeps double posting

 

I'm not sure what temperature the fan clutch should engage. Maybe that's normal, maybe it's not; I don't know for sure. Someone else will have to chime in. I don't know if you need a water pump; I said flush the cooling system first. If a bunch of rust flakes come out, I'd worry about the pump. But with that low of miles and age I doubt you'll have that problem. In all honesty, a cooling system flush is probably all you need. If you look in the radiator and it's rull of rust and the coolant is brown, then obviously you need to change it. I recommend flushing it instead of just changing it, because most likely the reason your motor is running hot is because the water pump can't push fluid through the block because of all the build-up.

Best of luck

 

Ok, i went ahead and completely flushed the whole system, i went and got some cooling system flush fluid and put it in and ran the truck for 15-20 minutes, then i have this flush kit that hooks a garden hose into the heater hose and flushes out the entire system. I got tons of brown water out but no flakes or larger pieces. In the end it didnt help. It was still running at 210-215, but i also didnt test drive it until the cool of after sundown.

Im wandering that maybe i got a bad t-stat, maybe it isnt opening all the way and it is restricting flow to the radiator. I know its an oreillys t-stat, but at the time i replaced it that was all i could get. And i had planned on putting a motorcraft in but never got around to it.

Another thing is that i dont think i would have ever noticed it running this hot if it wernt for the mechanical gauge i added. the stock gauge never got past the R in NORMAL

fmc400- thanks for all the help, i really appreciate it.

 

I'm sorry to hear that; it's always frustrating when something doesn't help. But it wasn't all for naught; brown coolant is definitely a reason for a flush. Maybe someone can chime in on the fan clutch temperature; if you don't hear anything in this forum for a little while then I'd ask in the 87-96 forum, since more guys over there would have the same style cooling setup. I still think that temperature is a little high; but maybe others will have more input.

 

A few things to check:

After you've been driving and the engine gets pretty warm 210-220 range, pull in a parking lot quick and make sure the bottom radiator hose is hot to the touch. Also make sure it is pressurized, also it may have a spring in the hose ( to prevent it from collapsing when the cooling system cools down or from pump suction)

Next, squeeze the top radiator hose with the engine at idle. rev the engine a little, you should feel the pressure in the hose build as you rev the engine. If not, then the t-stat may not be open, OR the pump impeller could be damaged -- or a combination of both.

One more thing you could check, have a helper rev the engine a little while you lay down to squeeze the bottom radiator hose, with your helper squeezing the top hose. You should BOTH feel pressure in the hoses when the engine was reved at the same time. Again, if the t-stat isnt open, or there is a spring in the lower hose, this test may be a little harder to check.

If the bottom radiator hose is not HOT to the touch:
1. the radiator could be clogged, typically a light flush cant fix this.
2. the water pump is not pumping a high enough volume of coolant
3. the radiator could be cooling TOO good, meaning bad water pump or tstat. (lol unlikely with the brown flush results)


My bet is a clogged radiator or bad pump. When you are at idle your engine runs cool. TYPICALLY people overheat while idling b/c of lack of airflow over the radiator. Your case is opposite, so you dont have a LACK of air, but a LACK of coolant VOLUME at highway speeds. Your radiator or pump flows just enough to keep your engine cool at idle, but under load at 2500+ rpms it cant keep up! It flows just enough for idle, but not for a load of some kind.

Finally, test your t-stat by throwing it in a pot of water and allow the pot to get to boiling, your t-stat should open just BEFORE the water starts to boil. This will tell you if it opens all the way too. (PRO TIP: do NOT use your wife's favorite pan, or any of her "good" pans/pots either... apparently just b/c a part with anti-freeze on it was put in the pan, it turns it into garbage??? *i dont know how that worked either*!! Ha Ha Ha)

And of course BE CAREFUL when you're poking around squeezing hoses, they will be HOT and close to moving fans, and belts!!!

Enjoy!

JT

 

JT- Thanks for the info. I went ahead and pulled the t-stat and replaced it, even after it showed to work ok on the stove.

I also did the other tests you described. The upper hose at idle is firm, nothing like it was before the flush. But, when you bump the throttle up a little it gets much softer. To the point where is can squeeze it shut with my hand.

As for the temps of the hoses, the top is really hot, and the lower is hot, but not quite as hot as the top.

Thanks again for all the help,
And please keep it coming.

 

It's normal for the bottom hose to not be as hot as the top hose (well that is the job of the radiator after all). When you squeezed it, was the truck warmed up, with the t-stat open? Maybe there is something different about the 300 I6 that i dont know of?? i, personally have never seen a water pump impeller rot away to nothing, but i guess it's possible. If i can think of anything else i'll definetely let you know

Good luck,
JT

 

ya, i expected the lower hose to be cooler. Iv never heard of a water pump going out without leaking a little. The truck only has 117000 miles and the engine is in really good shape. But i guess you can never know. The pump is my next item im gonna change if i can start figuring this out.

Thanks for the reply