1990.7.3 Ford deasel cooling problem

[Whitespider]

Ive seen it on three fords. The first pic on this thread shows one side is caught on the brass colored latch
Ford Escort Owners Association
Its the only pic i can find but it talks about it being ''fail safe''

kugss-
Those aren't a Ford or Motorcraft product, they aren't factory installed or OEM replacement. I did a Google search... They're marketed by a company called MotoRad and they're produced for nearly every make and model, not just Ford. It appears they're a relatively new (last few years) "gimmick" product that is just as likely to stick closed as open. If you read the reports, there have been problems with them sticking open or sticking closed for no apparent reason. I've never seen one installed or even for sale anywhere, and I can't for the life of me understand why anyone would want one.

 

[kugss]

kugss-
Those aren't a Ford or Motorcraft product, they aren't factory installed or OEM replacement. I did a Google search... They're marketed by a company called MotoRad and they're produced for nearly every make and model, not just Ford. It appears they're a relatively new (last few years) "gimmick" product that is just as likely to stick closed as open. If you read the reports, there have been problems with them sticking open or sticking closed for no apparent reason. I've never seen one installed or even for sale anywhere, and I can't for the life of me understand why anyone would want one.

Well life is a learning curve, ive only ever seen them in fords

 

[Dan_IN_MN]

Well first of all, if you added two gallons of plain water to the cooling system in -30 degrees you've most likely plugged the cooling/heating system with ice somewhere. Chances are good that some (or all) of the veins in the radiator are plugged and maybe the heater hoses and/or heater core. A plugged radiator will cause over-heating in pretty short order, and driving down the road with air rushing through the radiator will freeze it pretty darn fast. Plugging it in won't heat the coolant enough to thaw-out a radiator. The temperature sensor sensor needs to be submersed in coolant for it to read properly, and it the system is plugged with ice it could very well be that the engine is now "air locked", causing the sensor to be dry. An "air lock" will also cause the heating system to go cold and/or dry.

I agree that you need to figure out where the two gallons of coolant went (might just be as simple as a loose clamp somewhere or a water pump seeping), but first you need to get it in somewhere warm and make sure it's completely thawed out, and coolant is flowing through the radiator. If it, as you say, over-heated some 5 or so times you should definitely replace the thermostat and probably the temperature sensor, they're most likely trashed.

Keep it plugged in, you don't want that water freezing in the engine block because that could make for even bigger problems.

The water freezing was the first thing that I thought of too!

Second, like others have said, you need to find out where that coolent went!

I haven't workd on that engine....but been around the block a few times with cooling systems.

 

[flyfshrmn]

ford diesel cooling problem

I'm not sure when Ford corrected the coolant/cavitation on their earlier diesels. This problem was endemic to the 6.9 and the early 7.3 engine was just a slight redesign of the 6.9. The cavitation was a sonic cavitation caused by the focusing of shock waves from ignition on the cooling jacket wall. The remedy for this was supposedly maintaining the pH of the coolant, but it was not a problem that was found in all 6.9 engines. Eventually the cylinder wall would be breached and coolant would leak into the cylinders. If you have an aftermarket turbo (not sure when Ford started using the stock turbochargers) it could also be leaking coolant into the valley pan between the cylinder heads due to failed valley pan gasket which did not seal properly after the turbo install. This leak usually appears as coolant flowing off the back of the cylinder heads and appears at first to be a head gasket leak.

With the coolant that low, running the engine will give a false overheat due to the thermostat not being submerged by coolant. In actuality, your coolant might be even lower, because adding coolant to these engines was a tricky process. You had to fill the radiator, run the engine for a minute or so, shut off, bleed the pressure off the system and open the cap, then restart and fill with more coolant until the radiator was full. If you don't, then there may well be an air lock in the system, preventing the proper flow of coolant. Adding 2 gallons of water to the radiator will have taken your freeze point way up and these early model engines would run very cold in winter weather. If you had a plug, added water, and the water did not circulate past the plug, then your cooling system does not have a homogeneous mix of coolant and parts of it might ice up, such as the heater core.

To lose that much coolant and not have a visible leak indicates a pressure loss and gradual lowering of coolant accompanied by preferential boiling off of the water in the coolant. There are two sources for this which come immediately to mind, the first and most obvious being the cap. The second is pinhole leaks caused by internal abrasion at the top of the tank where the fins are welded to the tank. The radiator had a shelf at that point which tended to collect abrasive debris and the constant swirl of coolant circulation would cause small vortices which would eventually erode through the tank at that point.

Pressure check the system and the cap. If you have an internal erosion problem small pinhole leaks will appear at the top of tank. If the cap is bad, it won't hold pressure. The leaks can repaired by any competent radiator repair shop, but I suggest you look for someone with experience with this problem (i.e. an old fart mechanic) for the best results. You can pull the radiator yourself with minimal mechanical skill and the Haynes repair manual for this vehicle, if it needs welding. Makes the job a lot easier for the shop and cheaper as well.

If your leak is caused by cavitation erosion of the water jacket, there's no real fix except replacing the damaged portion of the jacket, as stated by an earlier post. You can sleeve the cylinder walls, but the truck would have to be otherwise mechanically sound to justify the expense.

 

[Jredsjeep]

can we link to other forums, i know of a couple that specialize in these spacific engines. you can get some very good spacific advice, although the advice so far has been very good.

 

[RVALUE]

I am picking up my new to me '89 7.3 next week.

What should I do at this point? Sell it?

 

[Jredsjeep]

I am picking up my new to me '89 7.3 next week.

What should I do at this point? Sell it?

heck no those engines are actaully really good engines. they are not the high horspower chipped engines but reliable, easy and cheap to work on. i can buy a set of 8 injectors for about $250, that wont even touch one of the newer truck injectors. the other wear part of the fuel system is the injector pump, you can get rebuilt ones for about 3-400. for this there are some shady ones online that rebuild i would find a reliable local to do it right. it can take some time to get the clearances set properly in the plungers of the pump and thats where discount places like to cut corners. pump and injectors are reccomended to be replaced every 100,000 miles or so.

besides that they are non-computer controlled simple diesel engines.

one of the big things to worry about is the collent addative. you can get it allong with the test strips very reasonably at NAPA or most any good diesel shop. the typical big box stores most likely wont know what you are talking about.

i have a 94 IDI in my F350 and i am not looking at a new truck anytime soon, i like this simple one to much and it does anything i need it to do just fine.

 

[RVALUE]

Are there directions with the test strips?

 

[Jredsjeep]

yes there are, very similar to reading test strips for a pool.

 

[fields_mj]

I run a 93 7.3 L. I would suggest going over to oilburners.net and going into their 6.9/7.3 IDI forum. That forum is THE place to go for help on a Ford IDI.

The cavitation problem that folks are talking about is real. It was pretty much non existant on the 6.9 because the thicker walls did not flex like those on the 7.3. Depending on what kind of coolant you are running, there are different additives. The most comon is DCA-4 which can be purchased at a dealership, NAPA, or any international dealership. International dealerships have the best prices. If you use Fleet Charge, it already has an additive in it, but it not the same as DCA-4 and it takes a different test strip.

I would agree that the water you added probably froze up on you. IF nothing is permanantly ruined, I would get the truck into a warm shop and drain the coolant, and add new. Then I would look for the leak, probably your water pump. Check your oil to make sure it doesn't have any water getting into it.

 

[fields_mj]

Are there directions with the test strips?

Yes, there are directions. However, I found the hole process to be a real pain in the rear. With a coolant flush, it will probably take 3 bottles of the addtive. I can buy Fleet Charge (with the additive already in it) from TSC for the same price that I can buy Fleetgaurd from the Int dealership without an additive. That made the choise an easy one for me.

If everything has been taken care of, you will really like your engine. Solid runner, simple and easy to work on, runs forever. I lot of guys who bought the 7.3 power strokes thinking they were going to get more HP ended up kicking them selves and wanting their old rides back. Those old IDI engines are second only to the 12v Cummins.

 

[olyman]

they dont like that at all, cavitation is a result of using coollent that does not have an additive.

basically what happens is without this additive every time the cylinder fires it flexes the cylinder wall a little. this happens so fast it pushes the coolent back creating a vacume. once the pressure stops the coolent slams back into the cyinder. this constant back and forth can wear through the cylinder bore from the backside eventually. additives give the coolent enough cushion to prevent this from happening. the older 6.9's were less prone to this than the later 7.3's since they were basically just a 6.9 bored out more.[/QUOTE]
close--

 

[olyman]

I have never heard of some of these things. Are these strips for checking lubricant common?

for checking--coolant!!

 

[tramp bushler]

wow thanks

Man you guys know your stuff.

Time for an update. The truck was plugged in from the time I got home on. There is a frost plug heater on both sides of the block. But no heater in the radiator system so the coolant in the hoses and radiator iced up. It musthave mixed with enough antifreeze that it didn't freeze solid. Even when it was 53 below. 2days later I could push mu finger down into it when I opened the cap. The trunk would start and run but I couldn't warm the truly up so I parked it and used my 3/4 ton Dodge 89 2wheel drive. The ex warmed up for a couple days but cooled off again. It s 30 below right now. 3 days ago I fired up the Ford. A friend who is a mechanicly minded Guy came over and we added coolant. Just regular anti freeze then some water. I haddn't been able to check this thread. The temp guage started working. I ran the truck for about 2 1/2 hrs inthe yard. Varied the r p m some. Test drove it and it seemed OK. Heater worked good. Next day I drove it 70 miles and everything seemed fine. Yesterday I took it to work and I'm sure the thermostat ztuk closed and it overheated on the way to work. It was Los on coolant again.

 

[tramp bushler]

I added mixed anti freeze to the overflow tank and it. Cooled off but the top radiator hose which doesn't have a spring inside it would collapse totally or partially. I went to work and the temp seemed good. Coming home loaded it would get up in the hot range pulling a hill but would cool right back off again. I can't find any trace of anti freeze in the exahust. And only one small leak where a hose clamp wasn't tight enough. There is NO sign of coolant in the oil. I pull the stick every day as I had some major oil leaks. I have the new thermostat in MT hand as I type this. And I need to get a new top hose with a spring in it. But I can't find where the thermostat goes. I know, how dumb can I be. I'm a bushler, not mu h of a mechanic. .. I can't really express how much I appreciate all the advice! !!!!!!!! . Thank you all.

 

[Whitespider]

Good to hear it's running again, and good to hear the freezing didn't do any damage.

The thermostat housing is on the end of the upper radiator hose. If my memory is still working properly you'll need to remove the alternator before you can even get a good look at it. And it seems you'll also have to remove the vacuum pump to replace the thermostat. Considering the disassemble required, I'd have the new upper hose "in hand" and do it at the same time.

Couple of things...
The truck may have been low on coolant again because of an air-lock somewhere in the engine; I think someone else pointed out that those engines a be a real pain to purge all the air, and I agree. If there was an air-lock, when you drove it the air was finally pumped into the radiator, making it seem coolant was lost.
The temperature gauge could be giving false readings because of the air-lock, because there's some air still cycling through, or because the temperature sensor got trashed.

In any event, the thermostat was probably damaged and should definitely be replaced. Possibly replacing the sensor would be pertinent, they're cheap and a good time to do it is during the thermostat job because you'll have the cooling system partially drained. And make sure you get all the air purged from the cooling system after doing the work.

Sorry I keep coming back and editing, still workin' on that first cup of coffee...
There are (I believe) three coolant temp sensors. One is located close to the thermostat housing and is used to advance the injection pump at cold temp, it doesn't feed the gauge. Another is located on the left head, towards the front and is the over-temp sensor, it only feeds the gauge in an over-temp condition and causes the gauge to peg at full-hot. The sensor that continuously feeds the gauge is located in the top of the engine close to the injection pump drive, has a single wire on it. If you leave the sensor out while filling the cooling system, and just screw it in when coolant starts coming out, it give a place for a lot of air to escape.

 

[olyman]

tramp--the alt will have to come off--to get at the thermostat--and make sure its a international,,or ford,,thermostat,,other brands arent built the same--tho they say they are..the ford one,,is specific... your top hose,,shouldnt need a spring in it,,when you get it working right--be careful when the cast iron neck above the thermo is taken off, as theres a small check ball in there......and make sure it freely moves in the hole its recessed in--

 

[tramp bushler]

Great . I found a leak in one of the back seat heater lines . I'm sure I lost some coolant out of that hole . I'm going to go out and hopefully successfully replace the thermostat and fix the hole in the heater line . I know I should replace the entire hose . But its kinda 1 thing at a time . The thermo I have is a Napa brand ,made in China . It says 88 C on it . I take it that's the temp it opens . I hope it works as the nearest Ford dealer is 150miles away .

 

[olyman]

Great . I found a leak in one of the back seat heater lines . I'm sure I lost some coolant out of that hole . I'm going to go out and hopefully successfully replace the thermostat and fix the hole in the heater line . I know I should replace the entire hose . But its kinda 1 thing at a time . The thermo I have is a Napa brand ,made in China . It says 88 C on it . I take it that's the temp it opens . I hope it works as the nearest Ford dealer is 150miles away .

get the one from Ford, thats one thing you dont need problems with!!!!

 

[Dan_IN_MN]

Great . I found a leak in one of the back seat heater lines . I'm sure I lost some coolant out of that hole . I'm going to go out and hopefully successfully replace the thermostat and fix the hole in the heater line . I know I should replace the entire hose . But its kinda 1 thing at a time . The thermo I have is a Napa brand ,made in China . It says 88 C on it . I take it that's the temp it opens . I hope it works as the nearest Ford dealer is 150miles away .

I would be willing to guess that your thermostat is okay. Being that you found a leak which caused a low collant condition thus the over heat. Sence it didn't overheat during your time spent running it in the yard and it only overheated once the coolant got low.

Replace/fix the hose, fill the system and you should be good to go.