cooling sytem problems and questions...

[flybear]

I finally got to drive the truck in warmer weather and I guess I might have some problems. The temp was upper 80's and after about 15 minutes at 65 mph (3000 RPM) the temp was almost out of the "normal" range. The "ENGINE" light came on. The coolant level is o.k., pressure cap works, etc. I had been using the AC, so I shut that off and slowed to 2800 rpm or so and the light went out. For the rest of the weekend the temp gauge stayed around the "A" or "L" in the word NORMAL on the gauge. Where should the gauge read if the thermostat is good? The rad looks very new on the outside and has a slight amount of buildup on the top of the tubes inside. (Not enough to make me think it's restricted). Since I don't know what type or how old the antifreeze is (it looks new also) I plan to drain and replace it. Is there a recommended brand that works better for the 6.9? I've read about the cavitation issues and will get additives and strips from my local NAPA store, as well as a thermostat if someone thinks my engine shouldn't be running this hot. I'm not even towing and it will be over 90 in a few weeks and I want to be able to use my AC, so I'm hoping I have a bad thermostat and this isn't normal for these trucks. As always, any input will be greatly appreciated. Thanks.

 

[Exekiel69]

If You are using the additive from napa then You want to use their coolant too, many use fleeguard (You can get it at the IH dealer) but napa works too. The t-stat may be the culprit, You can get one from ford fr $24, also it maybe something to do with Your fan clutch, did You hear it engage at any time? I have the modified fan clutch and I use it with the stant t-stat that comes in the kit = NO MORE cooling problems.

 

[Agnem]

Do yourself a favor and install a real temperature gauge pronto! By the time that engine light comes on, it's often too late. These heads like to crack under intense heat.

 

[ClassicIDI]

Not to hi-jack the thread but what is extreme heat. I have a autometer mechanical gauge and can often see 230F-235F while towing in the mountains. Should I be concerned?

 

[icanfixall]

Classic, If you had an auto trans I would say 235 is too hot because the trans is usually cooled by the motor coolant in the bottom of the radiator. Although it is cooler than the top its still hotter than you want. But thats not your case. The "check engine lite" comes on at 242 degrees. Thats hot. You need to look into whats causing this temp to go up. The easiest thing to check is the fan clutch. Then maybe the radiator or the thermostat. Has the thermostat ever been changed out?

 

[Agnem]

Not to hi-jack the thread but what is extreme heat. I have a autometer mechanical gauge and can often see 230F-235F while towing in the mountains. Should I be concerned?

Yea, if that is a sustained temp I'd try to find some ways to bring that down 10 degrees or so.

 

[flybear]

O.K., I've tried lots of things, still need help. Rad. flows good , pump is o.k. Bought new thermostat from NAPA, compared to old therm. in water on stove. Old one opened sooner and farther than new one, but I tried the new one anyway. Truck overheated. I've now been told to only get a therm. from Ford or IH, no aftermarket. Are they that different? I know they should not have a bypass in them, but what else is different about them?
Speaking of the bypass, when I had the therm. housing off, the checkball came out. What holds it in and can it be fixed? Is it even necesary? Just for the heck of it, I put everything back together without the checkball or a thermostat. I ran the truck at idle for a while and then drove it a few miles. The temp stayed low in the normal range. If I won't do it any harm, I may leave it like this for a while, just to make sure the thermostat is actually the problem.
I'm sure someone here has experience with the cooling system in these trucks, is there something else I'm missing or need to be aware of?

 

[icanfixall]

You need the thermostat otherwise you are bypassing a major amount of coolant and that will overheat because its not going thru the radiator. a real gage is necessary for actual temps. The stock gage is nothing more than an idiot lite with a pointer. You also need the ball in the housing. Its there to purge air out of the cooling system. Lots of guys have had trouble getting all the air out too. Only the Ford or International thermostat will work properly. Many have found this out the hard way. very few can run something other than that and get away with it but some have. I wont try it. The only temp thermostat that works and that you can buy is the 192 degree Ford or International one. What holds the checkball in place is a small piece of plastic. If its gone you could make another one or just buy another thermostat housing. If you make one you need to drill a hole in it so the air can escape thru it.

 

[Diesel JD]

Something is very wrong if you hit those temps not towing and its only in the high 80s. Have you had that radiator cleaned and checked to see if it needs replacement? Mud bugs or grime on the fins? Also... you really need a mechanical or electric gauge that gives a temp. You'd like to see it stay in that 192-212 range for eevryday driving and maybe 225-230 towing for a short period of time until the fan clutch cools things down. If I get much higher than 212-215 for very long it has me worried. The Ac as you found out will increase your temps...cut it off if they get too high and you should cool down quickly. As far as coolant any low silicate ethylene glycol is acceptable. And with the SCAs they are all good just don't mix products like avoid mixing Dca4/Ford VC8 or FW16 with CAT or NAPA or Carquest, anybody thats DCA2 or nitrite only. Also you can get diesel rated ELC but it may accelerate wear on already old oil cooler orings and you need to get as much of the old standard coolant out of the block as possible before switching over. Avoid the ELCs off the shelf in the auto parts stores designed for gassers especially the orange dexx cool stuff. It will only give you trouble.

 

[sassyrel]

it doesnt take a lot of calcium for the flow to be slowed down considerably---i do rads--just a small amount can cut flow in HALF!!!! have a rad shop boil and back flush the rad--that cleans a lot--though not all of it--rad has to be rodded to get it all out------

 

[flybear]

Thanks for the info.
I'm not suspecting the rad yet because when the engine is hot, the lower hose is still pretty cool to the touch. This would also explain why the fan clutch isn't locking up, not enough heat coming through the rad. The coolant is all new NAPA brand with their additive. I have a thermostat housing ordered at Auto Zone, I'm assuming with the checkball. Also getting a new pump, although the flow when looking in the cap with no thermostat looks o.k.
I'll call my Ford dealer tomorrow about a thermostat.
A "real" gauge will also be in the works.
Thanks for the help, any more info will be appreciated. I've been a Jeep guy since I started driving, and although I know them inside and out, I guess I'm going to have a bit of a learning curve with Ford and Diesels now. Oh Well, it'll be worth it, right?

 

[flybear]

One more thing, my info is that this cooling system should be about 7 gal. total. Is that correct? It doesn't seem like it's holding that much.

 

[creighta]

I put a new radiator in my 93 this week. I didn't do a full flush like I should have and it still took almost six gallons.

I found a truck stop that had the diesel antifreeze cheaper than Walmart!!