I seem to be losing coolant and I'm not sure where. I'm wondering if there is some trick to these engines that I'm missing. This is a 99 V-10 with manual tranny.
With the reservoir full to the cold fill max line, if I drive the truck any distance, the reservoir will be down a little bit each time. Last week I filled the reservoir to capacity, then drove home 11 miles. I forgot to check the coolant after that trip and started it only once after that to move it in my driveway. This morning I checked it and it was down probably six inches in the reservoir which was about 1/2 a gallon.
The truck does not overheat or run hot at all. I recently bought it and it has at least 101K miles but that may be suspect. I did a compression test which showed about 185psi in all cylinders. I did a full tune up when I bought it which included flushing the coolant. I bled it by leaving the cap off and letting it run until the thermostat opened. Heat was on. It would burble out of the reservoir a little bit until the thermostat opened then a big air bubble would pop up and the level would come down. I'd fill it quickly to make sure all air was purged. I did this several times until the air bubble looked like it was gone. Also, I squeezed the upper rad hose. There is no white smoke from the exhaust and the engine isn't hard starting. There is no coolant on the ground or on the engine that I've noticed. The radiator cap is new. There is no coolant in the oil. There was a little scum or foam in the reservoir when I bought it but that seems to be gone after the coolant change.
What am I missing? Is there more to bleeding these things than I know? I could try a leak down to see if maybe I've got a weak head gasket and am putting combustion products in the coolant but I hate to pull the plugs AGAIN. That job sucks on the V-10. That is really my only guess - if it is a weak gasket that is causing the cooling system to over-pressurize, maybe I'm pushing coolant out while driving. I hope not as a head gasket also looks like no fun! You would think the compression check would have shown that though.
Is there a known issue with these reservoirs or somewhere else that a leak occurs that isn't easily seen?
Thanks for the help. I'm pulling my hair out over this one right now. I'm ready to throw some Bars leaks in it and hope for the best.
Chk the heater hoses passenger side back towards the firewall and the rear plug hole for coolant.
Also look on the passenger side floor for anitfreeze (heater core leaking)
Do you see very fine bubbles in the coolant resvoir?
Have you done a coolant pressure test ?
You may have a head gasket going and it only leaks when hot therefore its going out the pipe slowly not enough for you to see or smell
Rich
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This won't help you much, but I've been reading these forums for several years and yours is the first coolant-failure problem I've seen, so I don't think there's any trick specific to the V10 that you should know about, like the "popcorn" plugs.
You didn't specifically mention whether you could smell coolant in the cab via the heater core, or whether you had inspected the floor mat for such possible leaks, but you've been so thorough that you just didn't think to mention it.
As to the liquid sealant, my son drove a 15-yr-old Buick cross country and arrived home with half his coolant missing and an extra 2 quarts of oil showing on the dipstick. At that age of course I didn't want to put any money in the car so I threw something in (don't remember the brand), and the car has run fine for over a year.
I'm not the mechanic that many people on these forums are, but it looks to me like you're running out of choices. Its especially distubing that you might be having run-of-the-mill head gasket problems at only 100K.....
Personally, I'd go for it, and put the Bars in, if only for diagnostic purposes. Then with the leak stopped you'll have plenty of time to work up a better solution.
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Thanks for the replies. I've used Bars leaks in other vehicles with good results but I'd rather find the problem first even if that is the way I "fix" it. I don't see anything at the heater hoses on the firewall and I don't smell it in the cab. I have not secifically felt the passenger carpet but I did have to remove trim panel on the passenger side to pull the plug on the inertial switch in order to bleed fuel pressure to change the filter. I didn't notice it then but I'll check. My gut is that it is not the heater core but worth a closer look. When I changed the coolant, I pulled the thermostat to flush it and messed up the o-ring when I re-installed. Coolant got all over the engine first time I ran it. As a result, it smelled like coolant for about a week or two but that is gone now. As for the possibility of the head gasket leaking only when hot, that is a real possibility, especially with an iron block and aluminum head I would think. I would expect more overheating signs with that though. I did have this happen on my race car (a Porsche 944 four cylinder) and it just lost water for a while until it got worse and the overheating started. I think I already know the answer is that it is a head gasket but I don't want to admit it I've read that the 99 MY V8s had some issues and they redesigned the gaskets. I'm guessing the V-10s are prone to this as well but there are less of them out there and therefore it isn't as well known.
I have not done a pressure test. I tried to make a rig with an air fitting installed in the old rad cap but I couldn't get it to work. I don't have the equipment to do it right and I doubt it will show anything if a compression test doesn't. I've heard of something like a Litmus paper or something that can show if there is exhaust gases in the coolant. Maybe I should look for that and give that a test. There are no obvious bubbles in the reservoir except for the foam that I mentioned before which doesn't seem to have come back. I'm towing the race car to the track with an enclosed trailer up in the mountains this weekend so I hope it doesn't get a lot worse quickly on that drive! I think I'm going to try using Bars leaks and draining the system to let it air dry as they suggest. I'll then carefully fill it and bleed it and see what she does.
Sorry for the several in a row posts! The strangest thing that I haven't really mentioned is the series of events the other day. I checked it at my house and it was full. I drove it to my dad's house 11 miles away. I checked it at his house after it cooled down and it was down a little (maybe half a quart). I topped it off and drove home 11 miles. Forgot to check it. Started the truck once to move it 10 feet. Checked it this morning and it took half a gallon! It seems that time is more of a factor than mileage which seems to indicate an external leak (if it were internal and filling the cylinders it would be at least hard starting or filling the oil) but there is nothing on the ground or engine. This is half a gallon missing! You would think there would be something somewhere.
Sorry for the several in a row posts! The strangest thing that I haven't really mentioned is the series of events the other day. I checked it at my house and it was full. I drove it to my dad's house 11 miles away. I checked it at his house after it cooled down and it was down a little (maybe half a quart). I topped it off and drove home 11 miles. Forgot to check it. Started the truck once to move it 10 feet. Checked it this morning and it took half a gallon! It seems that time is more of a factor than mileage which seems to indicate an external leak (if it were internal and filling the cylinders it would be at least hard starting or filling the oil) but there is nothing on the ground or engine. This is half a gallon missing! You would think there would be something somewhere.
Just send off an oil sample and look for the coolant percentage, shouldn't be any. That way you can pin it down a little. Still could be a head gasket leak w/o much oil contamination. If you are not seeing an external leak, say around the water pump, hoses or heater core then there is only one other place for the coolant to go inside the engine. You wrote that you do not have any bubbles in your coolant reservoir. I think that you can sample the coolant and get it tested for the presence of combustion gasses and fuel. I would say that the odds are that you have a head gasket leak. I have had them on other vehicles where the coolant did not go into the oil just into a cylinder a little at a time out the tailpipe. Power wouldn't even be down. Good luck with it.
forty is a ford tech so he's the one i would trust. you seem to have it well covered as to not showing and have added more then enough to be sure you don't have traped air pocket.
i would get or borrow a radiator pressure tester put it on ,not pump it up. start the engine and idle it up to see if pressure builds up in the system if it does it could be a head gasket or a cracked head. then with the engine off pump it all the way up and very carefully look all over for signs of leakage. another way you stated the paper test. still another is a black light test.have the dye added and useing a black light see were it gets found . just like a tech now checks a a/c system just a different dye.
just the amounts and time frame it takes. you should be something on the ground, smoke from the tail pipe or be smelling it inside the cab.. do you see anything odd from the a/c drain ? colored like antifreeze? with a stick shift theres not many ways to loose that much, radiator? water pump? hoses? core plug? heater core? cracked head or head gaskets . the oil cooler would pump oil into the cooling system or leak to the out side . have you checked all the hose clamps ? those factory spring types are bad and ford did have a tsb about checking them.
i don't do them the old way any more .i use the airlift system where you useing compressed air put a big time vac. on the system and then use that vac. to refill it. just like at the factory takes about 10 mins total at tops and you know it's full when your done. also if you do have a leak it will not pull down to a vac. and hold it as a way of testing the system.
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forty is a ford tech so he's the one i would trust. you seem to have it well covered as to not showing and have added more then enough to be sure you don't have traped air pocket.
i would get or borrow a radiator pressure tester put it on ,not pump it up. start the engine and idle it up to see if pressure builds up in the system if it does it could be a head gasket or a cracked head. then with the engine off pump it all the way up and very carefully look all over for signs of leakage. another way you stated the paper test. still another is a black light test.have the dye added and useing a black light see were it gets found . just like a tech now checks a a/c system just a different dye.
just the amounts and time frame it takes. you should be something on the ground, smoke from the tail pipe or be smelling it inside the cab.. do you see anything odd from the a/c drain ? colored like antifreeze? with a stick shift theres not many ways to loose that much, radiator? water pump? hoses? core plug? heater core? cracked head or head gaskets . the oil cooler would pump oil into the cooling system or leak to the out side . have you checked all the hose clamps ? those factory spring types are bad and ford did have a tsb about checking them.
i don't do them the old way any more .i use the airlift system where you useing compressed air put a big time vac. on the system and then use that vac. to refill it. just like at the factory takes about 10 mins total at tops and you know it's full when your done. also if you do have a leak it will not pull down to a vac. and hold it as a way of testing the system.
"Trust" who you like. So I am an only Engineer and not a "Factory Tech" that doesn't make me an expert or experienced on everything, but it does on many things. Seems like everyone is giving the same advice so I would go with the consensus. It is most likely a head gasket, based on the problem description. If accurate, and it all depends on how accurate the description is, the root cause can be pinned down by a few tests. Could be something simple and cheaper but you won't know if you don't do some testing. It should not be ignored until it is much worse. 106
Strange... with that much loss it should be pouring all over the place or smoking like crazy.
Check the oil, and if possible, actually drain it to see if there's any coolant in it. It's possible the oil cooler is letting it go somewhere... (I know, more oil pressure than coolant pressure, but ...).
Either that, or you did one very bad bleed job
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I've read that the 99 MY V8s had some issues and they redesigned the gaskets. I'm guessing the V-10s are prone to this as well but there are less of them out there and therefore it isn't as well known.
Just a wild guess...
