coolant overflow tank
 

Ok I found part of the reason for the coolant loss. My overflow tank is cracked Takes about 3 minutes for a full tank to drain. No biggie. If I can find one I can replace it. You guys are probably going to tell me its not stocked at ford so that will be bad. Out here in the desert junk yards anything plastic has almost definately deteriorated beyond use. Found that out while restoring a Mustang.
The second reason probably wont be so easy a fix. On the passenger side second glow lug from the front there is a puddle of nice lime green antifreeze in the area around the GP. i had found a thread on what caused it but cant find it now. It ws a gasket between the transmorgifier and the elunium pu36 explosive space modulator! Of course since this is my first diesel I'm sure you probably know it by a different name. Anyway.......... any guesses to how long a job replacing this gasket in the valley will take. I'm not a great mechanic but I do ok, but this is my first diesel motor like I said.
No oil in the water or water in the oil. No visable leaks in any hoses or from the weep hole. No evidence that it is reaching the harmonic balancer or fan and being slung around.
Oh and I thought it was a 6.9 but looking at the head bolts I think it is a 7.3. I'll have to verify a 7/16 12 point won"t fit first. they look like 1/2 inch but its raining and my glasses were wet so I don't trust what I saw just yet
Thanks

Can anyone tell me what years of coolant overflow tank will fit an 86 f-250. I'm going to guess 80 - 96

Take a pic of yours, and toss it on, then the rest of us can tell you if it matches what we've got or not.

They may be different from gas to diesel too, not sure off hand on that one. I know they are mounted differently.

When mine died I could not find a good replacement. I ended up getting the overflow / windshield washer fluid tank combo out of a early 90s explorer in the junk yard. A Lil creative mounting and have had it working for the past 2 years. Just another option for u

I didn't know enought to look and see if this one was a combo tank or not, but it is huge. Looks like it may hold 1.5 to 2 gallons. I'll try to get a pic up this weekend. The windshield wiper fluid tank is right next to it but I don't know if it is a one piece unit. Maybe i can use an old 2 gal plastic gas can I have laying around. LOL Then it would be purty.
I will still run into the problem of UV damaged plastic out here. We don't get a lot of rain so it is more common than not to pull the hood off a truck and leave it off. That white plastic crumbles into dust after a couple of years out here. But If I cant find the right tank I'll start looking in newer model trucks and fab up something. Thanks for the suggestion monte97z.

my 88 has not had an overflow tank on it in over 20 years. the stock plastic one cracked, so i tossed it. the radiator stays 1/2 inch below the top.

The later model gassers have a combined tank. Well, at least my '93 460 truck does. It's mounted where the drivers' side battery is on the diesels.

I feel that if I can fix this it will help me isolate my coolant loss. Last two times I have driven it I am well below the top row of fins in the Rad. Temp gage stays in the safe zone but I don't know if that is because of the temp sensor being out of the coolant or if it is reading the right temp. New to this engine but I'm learning. I don't see that much loss in the valley so something else is happening. I'm guessing it is overflowing sucking air and burping on every start and cool down and I just want the overflow bottle in the system.

Check ur hoses. I had a loss forever could not figure out where it was coming from. One day my lower hose started leaking at the Rad little drops not much but I finally noticed it. Replaced the hoses and have not lost coolant in 6 months. Stays right where it should be.

Checked the hoses last night and could not see anything. Not sure what the water temp was at the time when it was running. might not have been flowing. Just that small puddle around the GP on the passenger side

As coolant heats and expands, it has to go somewhere. If your radiator is full, the pressure release on the cap lets the coolant flow out to the overflow tank. Once the engine cools down, the coolant shrinks back down, and the cooling system is at a vacuum and thus will suck the coolant back in from the overflow tank. The overflow tank isn't pressurized, so you could substitute virtually any tank you can find a way to stuff the hose into.

TJC's truck has some air space above the fluid in the radiator that allows the coolant to expand without spilling out. If needed, air will be pushed out of the radiator cap and sucked back in as it cools. The only problem here, is that its harder to check the coolant level. With an overflow tank, if some leaks out, the system should be able to suck new stuff in after a warming/cooling cycle. You can monitor the level by checking how much is left in the overflow tank. This will only work for small leaks. Large leaks will just bleed out coolant and could suck in air, or not allow the system to pressurize and then suck when cooled down.

I just had to replace my water pump, and didn't get a chance to pick up new coolant before doing it. I recycled what I could back in, but was about 1/2-3/4 of a gallon low. I ran it about 2 weeks before I had a chance to stop and get some new stuff and had no problems.

Yep. Thats what I think is happening. The 6.9 (verified with head bolt size) was replaced a couple of monthe ago by the PO. I think the coolant system may have a big bubble in the block and its purging coolant into the cracked overflow tank. When the engine cools it sucks in air and the bubble never gets removed. This is all a guess of course. I have not stayed at a Holiday Inn for a while now.

This week I kept filling the Radiator whenever it was cool enough to take the cap off. It took a little less coolant each time I checked and it stabalized about a 1/2 to 3/4 of an inch below full. The PO had replaced the engine a few weeks before I bought it. What I am going to guess happened was there was air in the coolant system. When the t-stat opened up and the air came out it would expand and force out the coolant. Since the overflow tank is cracked the coolant would run out and as the engine cooled it would suck the air back in.
I had something similar happen to a 302 I rebuilt. Everytime the coolant started pouring out of the overflow I would kill the engine. It was in a vintage mustang and the overflow was one of the purty chrome jobbers that only held a couple of pints This only prolonged the problem. I finally had to let the coolant purge out the bubble and then add to the overflow as it cooled. Never did it again.
I have a feeling that if my overflow was not cracked it would have worked as advetised and I would have never seen this problem. i have a plastic gas can about the same size as the stock overflow. I'll rig something up with this till i can find a working stock unit. Hey it beats a 2 liter soda bottle.

or just walk around a local salvage yard with a tape measure,looking for one that will fit.doesn't need to be stock.

LMC has new ones but they are $99, I patched mine with Blue Permatex and it has held for over a year...