QuestionHi, Steve. I've been corresponding with Tim Lantry about my car problem, at:
www.allexperts.com/user.cgi?m=6&catID=811&qID=4596563
…but I had some followup info and questions that I haven't been able to send to him because his question quota has been used up for the past few days. I'd like to tell you some of the things that have happened after my posts to him.
I've got a lot more info on the problem I'm seeing with my Taurus, all of which I think might be relevant, but I apologize first that I've got so much to report here. Bear with me as I relate this long series of observations, and let me know if this is more input than you would normally handle.
I followed Tim's advice about putting water into the radiator to try to remove any air pockets from the cooling system. That didn't get the cabin heater to work again, but it did seem to accelerate an engine overheating problem that originally started about a week after I washed the engine and the heater stopped working. While I was putting the water into the radiator, using a garden hose, the tailpipe put out a lot of puffy white smoke, which I've read can be a sign of either a blown head gasket allowing coolant to get into the cylinder, or water in the oil. I don't remember if I left the water in the cooling system while I drove the car around later, or if I added some antifreeze, but within a day after this water flush, the engine began to overheat a lot more, and kept putting out puffy white smoke about a minute after starting the engine, so I kept putting in 50/50 antifreeze and water until it reached the point where it was all a 50/50 mix. But the white smoke continued coming out of the tailpipe, and the overheating got even worse, to the point where the engine now overheats after driving only about a mile at 25 MPH. The coolant seems to also be under higher than normal pressure, since it's squirting out of a fitting on the radiator where a metal tube enters the left side of the radiator, about three inches below the radiator cap. I keep having to fill the radiator with coolant due to this leak, but the engine overheats first, before enough coolant has leaked out to cause the overheating. It's as if the coolant isn't flowing very well, due to some blockage, or something that's not opening up enough to allow the coolant to flow.
I've bought a replacement thermostat, but I haven't installed it yet, both because I haven't had time, and because now I'm doubtful that the problem is the thermostat, or only the thermostat, because of a new symptom that happened yesterday: while the engine was cold, I tried to start it up. It wouldn't start the first time, but ran rough instead, so I turned the key again, and it sounded even rougher, far rougher than I'd ever heard it, so I turned it off. I heard hissing from under the hood, and found that the leaky fitting on the side of the radiator was leaking again, even though the engine hadn't had time to get hot. I felt the leaking coolant; it was cold. So now, as soon as I start the engine, it seems that it's creating a lot of pressure in the coolant system, causing the leak--is this further confirmation of a blockage of some sort, or a valve in the coolant system that's not opening up, that should open even when the engine is cold?
Is the thermostat supposed to always be a little open even when the engine is cool, to allow the coolant to start flowing early, and then when the engine heats up, the thermostat opens even more? Or is the thermostat completely closed until the engine heats up? If it's closed until the engine heats up, I assume there are other parts of the coolant system where coolant flows before the engine gets hot enough to open the thermostat, so maybe that's the part of the system where the blockage might be.
Another reason I doubt if the radiator leak is causing the overheating (at least right after the engine has been started, and before the leak gets bad), is that the overheating first began when the leak was only a few drops--to me, it seems that the overheating has some other cause at this point, causing the coolant to boil over and leak out the fitting, which might then further increases the overheating. Could even a small leak mess with the cooling system's pressure so much that it would cause overheating? I'm pretty sure that the amount of coolant that's now leaking out after the engine has been running only a few minutes, isn't enough to cause the kind of overheating I'm now seeing, and I doubt if the pressure problem the leak is causing is creating much overheating (correct me if I'm wrong), so I still suspect something else is causing the overheating, and the leaking might be making it worse, but not by much until the engine has been running longer. I also wonder, what's the function of the metal tube that goes into the leaky radiator fitting, below the rubber hose that runs from the radiator to the coolant recovery reservoir? Is it delivering coolant into the radiator, or is it acting as a kind of overflow tube?
It seems that if something is blocking the cooling system, it's getting worse fast, as if there's a partially blocked spot with a small hole remaining, that's quickly getting filled in more and more. Or maybe some sensor (maybe the temperature sensor?) that gates coolant according to some measurement it makes, is bad and getting worse? Could the water pump be involved? How do I tell if the water pump is working? I'm also still considering that a blown head gasket is causing coolant to leak into the cylinder, further contributing to the overheating, but is there another way to tell if the head gasket is blown?
Am I on the right track in any of this? I'm not starting the car until I've done a few things like replacing the thermostat, flushing the cooling system and heater core, etc., and some other things to try would be welcome. I've bought a Chilton manual, and I'm pretty handy, so I'll see how much I can do before taking it to a mechanic. Thanks for any help.
AnswerJohn-
Well...I could honestly come up with half a dozen possible reasons that would explain any or all of your problems. Air pockets in coolant can be problematic, but they're easy enough to neutralize. Take that new thermostat and drill a small hole in it...maybe 1/4". It will prevent the bubbles from getting stuck which will prevent false readings from the sensors. However I'd imagine the problem is probably worse...either a cracked block, blown cylinder head gasket, cracked head, or blown intake manifold gasket (I told you there were a lot of explanations). Basically to get white smoke you need to be burning coolant and any time coolant is in the combustion chamber it's bad news. To find out if it's a head gasket/block/head problem, you can do a leakdown test or a coolant system pressure test. Both require special tools that aren't exactly cheap, but they'll give you a better idea of what's going on. If either test turns up ok then I'd just replace the intake manifold gasket. Hope this helps.
Steve
