Hi there. It sounds like you have done the most obvious checks and I can assure you by-passing the heater core will have no effect. There are three possible causes that you need to investigate further and you will need specialist equipment for it - you either have a hair-line crack in the head or cylinder wall or it might be that the head bolts are stretched and therefore weakened and so need replacement. To help you identify these aforementioned possible problems, you might need a specialist fluid that you put into the cooling system which changes colour when combustion chamber pressure enters the cooling system, you need to contact your local Ford Dealer for this - but then you still have the three possible problems to deal with - cracked cylinder wall/s, cracked head or stretched head bolts. Hope this helps, Scottech.
Hi there. To answer your comment posted 18th June, the problem you have here is all engines have hot spots and this might be eaxctly where the weakness/crack is. Thus the engine and in this case the cooling system can work normally for a while and then all of sudden the water is pressurised out of the coolant expansion chamber. I had the exact same problem with a Volvo S40 T4 where it would run fine and for no apparently reason the water would all of a sudeen be forced out of the expnasion tank. There was no signs of oil or contamination in the coolant. Becasue the engine had previously been overheated, we removed the head, couldn't see any crack, but we did replace the head bolts becasue we knew that they would have been stretched. After this, the problem was still there and so we visited the Volvo Dealer and had them undertake a special fluid check which identifies combustion emmission into the cooling system and that was still positive. In the end we replaced the cylinder head - problem gone. Thus there must have been a hair-line crack with head at a particular hot-spot which was not visible to the naked eye. Also, becasue the crack was in the head it was only combustion pressure going into the coolant, thus there was virtually not visable signs of contamination in the coolant. But, the most important things to keep looking at firstly are the basics, is the radiator free of blockage (tip - when at normal operating temperture and immediately after a short test drive feel the whole area of the radiator's surface. If you feel any cool areas, you have a blockage there) also, and this is often overlooked, is your water pump working? It might be that the pulley is being driven by the belt, but I have seen water pump shafts shear and what appears to be driven on the outside is not being driven on the inside - in this case your waterpump impellor. Bottom line though, I still think you have a hair-line crack in the head and you need to perhaps seek the expertise of the franchised dealer to bottom-out whether you have a combustion leak into the cooling system - sorry I can't be any more help here. Hope this aditional feedback does help you. Scottech.
Hi there. I appreciate your feedback and absolutely, the best practice is to always check and tick-off the basics, cooling fan operation of course being quite fundemental. It's the termostat that controls the most effective engine coolant operating temperture and of course the cooling fans are there to help cool the temperture of the coolant from the engine. Given the fan might be kicking-in too quickly, this might be as you correctly identify a faulty switch, becasue whilst at times it might be switching the fan/s on too soon, it might also not be kicking-in when the cooland needs cooled down. There is no harm in running the fan/s all the time, so if you wanted to, you could disconnect the sensor bridge the connection so the fans run continuously as see if that resolves the problem in the short term. Hope this helps you further. Scottech.
Hi there. Just a thought about flushing the system, given you have found some rust in the hose between the manifold and expansion chamber, have you been able to flush the block? Normally you will find a screw/bolt in the side of the block where water can be drained from the block. I'd strongly recommend that you not only flush the system in one direction, but also back flush in the opposite direction too - do the same with the radiator. However, before flushing the engine in both directions, always firstly remove the thermostat to allow complete circulation. Whilst you are at it, there is no harm in disconnecting the internal heater matrix and flushing that through in both directions - if you can do this without the inlet and outlet hoses connected to the engine all the better. The less rubbish washed through the engine, the better. Hope this helps. Scottech.
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Ok I would try this.... I would replace the radiator cap once morewith a new one. when I do this I would look at the radiator where the cap seals. is there any anomally there? I would look into doing a pressure test on the coolant system.
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There is also no coolant in the oil or oil in the coolant.
Did a block check today. No combustion gases present in the cooling system. If it were a cracked block/head/cylinder wall, it would be showing combustion gases in the coolant. On top of this, wouldn't the car continually overflow if the block/head/or wall were cracked? I'm wondering if the chemical flush has loosened scale or rust in the heater core and moved some blockage into a hose or into the radiator itself. Any other solutions?
scottech, I appreciate your help, but the special fluid you're talking about is the same test I performed today (06/18/09). This test came up negative. I don't have emissions gases in my coolant, so I don't think it's a cracked head,etc. I am leaning more toward blockage somewhere that would restrict flow. Also possibly the coolant temperature sensor. The cooling fan kicked on after idling for nearly 15-20 minutes and only for about 20 seconds.
Checked the Engine Coolant Temperature Sensor today and was getting an infinity ohms reading on it. Replaced. Found rust blockage in the uppermost hose that comes from the lower intake manifold to the expansion tank. Cleaned that out as well. This is a hard part to find, would have to contact the dealer for a new one, but I did flush it until I could blow through the hose with little to no resistance. Used a piece of romex to break up the rust and flushed through with water. Looked at the radiator cap. I can push on it and it will move a little if I use two thumbs. Not sure if it did this before, but if it fails tomorrow I will be replacing the cap as well. The expansion tank itself seems to be okay though.
Thanks for the advice, scottech. I have flushed the radiator both forward and backward and ran a chemical flush though the entire system. I can't seem to find the core plugs that will drain the fluid from the engine block itself, but my coolant isn't turning rust-colored anymore. When I took the ECT Sensor out, the threads were caked in rust, as was the back of the sensor. Wrapped the new threads with teflon tape and installed the new sensor. We'll see how she runs today.
scottech, please see the thread Here's a wierd cooling fan issue to find out what the issue was for this automobile.
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