[Chayson]

I have a 2000 F250 2wd. 187000 miles with not too many problems. 4 weeks ago, my temp. went to red so I pulled over and let it cool. Had to add about 2 galons of water to get it going. Took it in the next day and they did a flush, pressure test and changed the thermostat... all's well. Ran great for the next 24 hours. Folling day, I had to head up to Tahoe (long steep grade)and same thing happens (engines over heats). I pull over and had to add 1 gallon of water to get me going as well at turn on the heater to help with the temp, (keep in mind the tempeture is 40* outside so it's not a hot day). I drive aroud town with no problems for a few hours and then head for home. Up the grade, same thing happens and I pull over and have to add 3 more gallons of water with no signs of leaks. Take it to the shop next day and they do another pressure test and flush the engine again. Truck runs great for the next 2 weeks with no problems till the next time I go to Tahoe. Same grade, same thing except this time by keeping the heater on, the tempeture goes down to a safe level. Heater in not needed at any other times. This time, the engine start to heat up in town on flat freeway while the A/C is on, so I turn on the heater and temp. goes down. My mechanic is a good friend and 1st susspected the fan clutch. After a couple of thourough checks, he's not sure what it is but want to probe deeper by pulling things apart to diagnose (he does this for free so $ gowging is not an issue).

He feels the truck has a huge loss of power and should be more responsive and powerful. He thinks there's something wrong with the turbo. I've had the truck so long and it's run pretty much the same that it feels normal to me. There is some history behind his assumptions as I had issues with the truck while it was still under warrenty (around 30,000 miles)from repair from the dealership. Any help is appreciated and if the prior problems would help the diagnosis, let me know and I'll post them. Thanks in advance.

 

[haul_n_horses2]

Well I do not know the answer to your problem, but it seems to me that you need to find out where the coolant is going. If it is not leaking and you do not have a cloud of steam coming from under the hood, then I am guessing that you have some pinholes in the cylinder walls due to cavitation and that the coolant is be lost through combustion. When the coolant levels get low and you thermally challenge the system you overheat. If this is the case, you will need a major overhaul with a lot of machine shop work to put in new sleeves etc. What coolant have you been using and have you been paying attention to the supplemental coolant additives that prevent cavitation damage?

 

[AutoJim]

There's also the possibility that the water pump impeller, which is a steel stamping, has eroded and isn't able to move enough liquid to get the job done. But with no external leaks and a consistent coolant loss, I'm thinking there's either a head gasket that's gone, a head is cracked, or, remotely, what haul_n suggested about the block. I'm leaning toward either the head gasket or head, though.

So I'd check things in order of complexity:

1) pressure test the system, starting cold, then warming it up. See if it maintains pressure or drops off. Given what you're saying about coolant loss, it *should* drop off if it's not venting the stuff out the cap.

2) make sure the heat exchangers are free of crud on the air side, and the radiator isn't all gummed up inside. This will involve a bit of disassembly so you can get between the radiator and CAC. I've found all manner of weird stuff (like lots of grass -- I don't go off road At All, but there's grass there?!?) in my truck which has similar mileage (turned 188K this past Sunday).

3) check the water pump. If the impeller is eroded, replace the pump with a fresh one.

4) Check the injector cups in the heads -- if they've shifted, or corroded, that could be a cause of the coolant loss. They *may* be replacable without having to pull the heads, but I'm not certain on that.

5) Now things start getting expensive, because both heads will need to come off if you haven't found the problem by now. Check for evidence of a blown head gasket, then inspect the heads -- I'd go ahead and have them disassembled and Magnafluxed, if the gasket appears to be intact, in order to find any cracks.

The key is in doing a proper diagnosis. Start simple and work toward the more complicated (read: expensive) checks in a logical progression rather than "shotgun debugging" by throwing semi-random parts at it.

Hope this helps,

 

[mjl38351]

[ QUOTE ]
2) make sure the heat exchangers are free of crud on the air side, and the radiator isn't all gummed up inside. This will involve a bit of disassembly so you can get between the radiator and CAC. I've found all manner of weird stuff (like lots of grass -- I don't go off road At All, but there's grass there?!?) in my truck which has similar mileage (turned 188K this past Sunday).


[/ QUOTE ]

I work on garbage trucks and see this all the time. In addition when I got my Super Duty it had 173,000 miles on it. I installed the Banks kit and during replacing the CAC I found a area in the center on my radiator about the diameter of a 5 gal bucket that was clogged with hay (grass too!) <font color="red">In my experience with the garbage trucks the single most common cause for over heating has been obstructed air flow thru the cores. </font> You should realize that you have the A/C condenser, then CAC, and finally the radiator. A little bit in each creates enough loss of air flowing through that the heat can not be removed as fast as it is generated.

You can not clean them by taking a water hose and flushing through the grill trying to clean all of them at once. you will HAVE to separate the condenser - CAC and radiator to clean each individually in order to properly clean debris out. Other wise you'll just clean the condenser out and flush that debris to the CAC. You will not see any reward for you effort this way.

One other point sometimes over looked is when the cores are obstructed in this manner air can not flow through them and cause the themostatic sensor on the fan clutch to operate properly as it NEEDS heat to know when it needs to make fan clutch engage. With the miles you mentioned my money is on debris blocking your air flow. The good part of this is it doesn't cost you anything to fix, if you do it yourself. Also I would expect you to see a little better cooling from your A/C as well once the air can flow thru freely. /ubbthreads/images/graemlins/wink.gif

 

[drmiller100]

like they said, where is the coolant going?

i'd bet on the headgasket. started out only under load (ie turbo spooled up), progressively getting worse is pretty classic head gasket to me.

is your oil milky? when it over heats, is it blowing coolant out the top?

does it occasionally start blowing coolant out just BEFORE it overheats?

 

[mjl38351]

When our trucks over heat, they usually need 2-3 gallons to refill them. I offered suggestion based on what I see probably weekly at the least in warm to hot weather. Yea, you could pull the motor out and start doing the most expensive things first, and clean the cores while they are out; but why not try something simpler and cheaper first, then see what happens? you could be right - could have been ran too hot or too hot too many times and blown gasket. My experience with Mack trucks was if a head gasket was blown where compression got into cooling system it would blow coolant out regardless of being under load or not. More so hot and driven, but you just increased the cylinder firing events in a given time and speeded up what was happening anyway. Hopefully we will here how it all turns out.

 

[Big94Ford]

I had a pin hole leak in the plastic (pressurized) expansion chamber. Could be atomizing out of there (like mine was) and not building any pressure as a by-product.

 

[mjl38351]

any news or updates? /ubbthreads/images/graemlins/shrug.gifWe would all like to know what you've found

 

[2180]

any updates i have a 2000 f 350 doing the same thing that im working on overheating and pushing coolant on a heavy pull on a hill with turbo spoled up