Hey everyone, I have been looking around to try and find my answer, but no avail.

My F-250 seems to run hot to me. My problem is that the factory gauge cluster does not work well. The gauge will get stuck, smack the dash and it jumps around. So to get a good read, I installed after market gauges. The problem I have is that the factory cluster only reads normal, not anything a deg.

So my question is what should I expect to see as normal temps? I have a 180* stat as I tow a heavy trailer most of the time, but from what I have been reading it might be better to go back to the 195 that was stock and use a heavy duty stat.... not sure yet.

Anyhow, I have seen temps as high as 215 when pulling the trailer, but I am not sure how hot I can get before I should worry.

Truck has a new rad, internal tranny cooler, new water pump, new timing chain and gears, plugs, wires, o2 sensor, cap/rotor, wires, plugs... Air filter... fuel filter. So all the major tune up junk. I have serviced the tranny and installed a new TC since the old one had to come out because the oil seal was leaking.

Anyhow. The truck still seems a little hot to me, but the only thing I own that gives a deg readout is my street bike, and if it gets to 220, that is HOT.

Thanks for any info that you might be able to give that can help me make sure I am ok.

John

 

I'd invest in a flex fan, one with the wide blades, for one.
For 2, I would check the hoses and keep the 190 thermostadt, for that what it calls for. Keep the rad clear of debris, dump the internal cooler and go with an HD external cooler.

 

I will confirm the hoses, the rad is clear and the fan shroud is in place. The fan clutch was also replaced as well. It seems to work correctly as of now.

My plan was to dump the internal cooler if needed.
How much help is the flex fan and what is that going to do to the MPG? It kinda drinks a lot of fuel as it is. lol
No load I am getting about 10mpg right now. The tires are little taller then stock (I would have to look at the sizes to remember) and I do not know what the rear end is geared at (Stock for sure, just dont know the numbers on it).

But even with all of that, I am still not sure what a safe range is for running temps.

Oh yea, Truck has 175K miles on it.

John

 

Where are you reading the temperature? Do you have something other than the stock gauge or not? Anywhere from maybe 185-215 should be okay, but I wouldn't go much above that.

With cooling problems, switching to a flex fan that decreases airflow at speed is probably not a good idea.

 

So over 215 is bad?

I do have autometer gauges. I have installed the sending unit in place of the OEM on the intake manifold (if I remember correct that is the location). I know it replaced the OEM unit.

I do also notice that I have crack in one ex manifold (I can not remember but I think it was driver side) if that might have anything to do with it.

My thought would be that a fan clutch would be better then a flex as the clutch will only lock up when needed, correct?

Thanks again,
John

 

Gotcha on the temp gauge. 215 is probably okay, but I wouldn't want it to get much above that for an sustained amount of time. You should be okay with the stock clutch fan since it should disengage when not needed (it won't free-wheel or stop spinning altogether, but it definitely runs faster when engaged). The crack in the exhaust manifold could cause a lean reading on the O2 sensor which would be cause for the computer to richen the mixture. This may be part of the low fuel economy, but that's just a theory.

 

Yea my thought was the same for the crack, but I was not sure if it would effect the temps that much.

I have seen the temp get over 215 a few times, only once since the new Rad was installed last summer. I just like to know how hot I can get before I have to worry. Like on the bikes, one bike is safe at 220 and others are safe to 250...

Thanks again.

 

Maybe this is ignorance, but when it starts boiling over into the reservoir tank, it is going to start vaporizing a significant amount of your coolant. I would think the engine would be safe until you have a lot of vapor in the upper part of your cooling system. Then, where there is no liquid contact, temperatures are going to skyrocket. In summary, I wouldn't worry unless you have steam coming out of your reservoir tank.
Sincerely yours, Rod

 

Hummmm but when driving, it can be hard to tell if it is steaming, no?

I have never had it steam, but I have had it boil once on me...
I am taking a trip to laughlin in a few weeks towing a boat, so we will see more about what it acts like.

John

 

"With cooling problems, switching to a flex fan that decreases airflow at speed is probably not a good idea."

When at speed, you have what is known as 'ram-air' and the flex fan flattens out, creating no drag. When you slow down, no matter how much, the flex blades re-form, to pull air thru the system. The slower you go, the more air is pulled thru. (Yes, the mph/mpg is comprimised, but the cooling will be effective.) Good for towing.

With a clutch fan, even a short to mid time stop, the blades haven't engaged yet. I'm not here to sell the idea, but the physics speak for themselves.<!-- / message --><!-- sig -->

 

You should be ok at 215 deg F. The big issue as someone mentioned is to avoid boiling the coolant. I assumed you are using a water/antifreeze mix eh?
Not to get real techinal, and using rough numbers, water boils at 212(at sea level) but the pressure in the system raises the boiling point. Roughly 1 lb of pressure raises about 2.5 deg. If you are running a 12psi radiator cap, the boiling point is somewhere around 240 deg. At 215 you are well below this. Some internal parts of the cooling passages will be hotter than others, but there should'nt be a problem at 215 or even 220.
Just my opinion.
Good luck Frank

 

I am currently running a mix in the area of 30% coolant and 70% distilled water with a bottle of water wetter in it.

So if I am understanding correct (I am not great with cooling systems as I have never really had to worry about it in the past), so long as I am not boiling over, the temps should be ok? I think the last time it boiled over was over 220 and we stop to let it cool down. Since that time, I have reaplaced a few items to help improve the system.

What do you all think about a cooling system flush? Could it be that the block is gunked up and causing a problem?

Would a Heavy Duty thermostat be better then a standard thermostat?

If the temps are still an issue when I tow in a few weeks, the tranny cooler is the next items to change, that is quick and easy... But I am always looking for a way to make it better.

John

 

Thermostat wise, I run the stock temp, and prefer a premium thermostat made by Stant. It is supposed to open up if it fails. The stock temp is needed to get the engine up to operating temp so the computer can do it's job with the fuel injection.
My experience has been if an engine is over heating, a cooler thermostat just adds a little time to how long before it overheats. It doesn't prevent the overheating.
I flushed my cooling system well with Prestone engine flush just before I replaced the radiator. Thinking whatever broke loose could get tossed out with the old radiator.
I would not think a tranny cooler would make a large difference on the engine cooling system, but could make a big difference on cooling the tranny.
From what I have read, the water wetter has good marketing, but not much else. Our weather runs from 20 below to 110, so I run a 50/50 mix of coolant.
Good luck Frank

 

I have used water wetter in the bike (granted they are all aluminum motors) but I have seen the change when moving. It does basically nothing at a stand still for the bikes. Once we get moving, the does make the bikes cool down a bit faster. Not sure with the truck.

I agree that the stat being lower would likely only delay the over heat. I am going to be using the premium Stant stat. That is going in next weekend along with a good flush.

I have heard over and over to remove the tranny cooler and go external... That might be the next step, but my tranny temp never gets more then 150 at this point. I will see how that does when I tow with it hooked up. lol

thanks guys!

John

 

The physics are that a rigid fan will pull more air at speed when demanded by the fan clutch than a flex fan, without question. I've pulled a trailer with a Yukon and climbing hills at 70 mph and 3000 engine rpm, I could hear the clutch fan engage and disengage. At these engine speeds, a flex fan would be flattened, rendering it ineffective which would cause the engine to overheat since there is no way for it to increase airflow through the radiator without slowing down. A flex fan is on-off with engine speed; a rigid clutch fan is on-off with radiator core temperature...that's the key difference.

You are right about the boiling point info. However, the engine can be affected by high temperatures even if the water is not boiling. The thermal expansion of the block, heads, and things like valve guides may not always expand equally and could cause problems. Plus a hotter engine is more susceptible to knock and will make less power than an engine running at normal operating temperature. The engine computer on mustangs begins to decrease ignition advance and richen the fuel mixture when the engine temperature gets elevated (220 is the ballpark for these changes to occur). 220 likely won't hurt the engine in the short term, but I would not run it that hot for extended periods of time.