This is kind of related to a previous post I had........For some reason my 2001 XLT temp gauge in the dash all of the sudden went all the way to the hot side and my coolant light came on while I was driving one day. I stopped, shut it off and checked and there was no overheating at all and no coolant coming out anywhere....no sign of an overheat at all. I shut my truck off for about 5-10 seconds and restarted it and the gauge then had dropped quite a bit and the coolant light went off. I continued to drive and then it happened again about 10-15 minutes later......I checked everything again and nothing. Shut the key off again and restarted then the light went off and sensor had dropped again. This continued on/off for several weeks then one time it did it and the check engine light came on and went into "safe mode " where the truck would still run but would go very slow. I was able to get the code read and it was P1299. I got the cylinder head temp sensor changed (CHTS) the same day but the problem came back the next day. The truck has never actually overheated.....just indicating that it was. Obviously coolant doesn't cool off in 5-10 seconds so I would have thought it was the sensor. I did notice that after replacing the sensor and it starting acting up again that turning the key on /off didn't drop the temp gauge anymore (it did drop after leaving it set for awhile). It seems like the longer you drive it the more likely it will happen although it doesn't happen everytime ( I even left it running in my driveway for an hour after driving it and it didn't do it ). Has anyone had this issue or have an idea what or where to look next? Any help would be appreciated.
Coolant sensor/ possible cooling issue/code P1299
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bedrck46
Have you checked the coolant level??
stamp11127
Full Access Members
As bedrck said, coolant level, bleed air from system, could also be a failing water pump.
What kind of coolant are you using? If you don't know, what color is it?
What kind of coolant are you using? If you don't know, what color is it?
The truck has been sitting for bout 2-2.5 hours now and the level is about 1 -1.5 inches under the cold mark on the tank. The coolant is green (brownish green now). I had the cooling system completely flushed approx. a year or year and a half ago. Any more input would be great!
stamp11127
Full Access Members
No, the different colors represent the different mixtures. Is the brown color oil, leak fix or rust?
IMINYOURCHAIR
Full Access Members
go ahead and fill the tank up to about full. if it is low it will need to be that full to draw more in and push the air out. in my experience the air tends to pool in the upper rad hose so give it a squeeze after you fill it up.
As far as the color goes I assume it is rust......nothing has been done since it was flushed and there were no leaks as far as I know (I wonder if it needs to be flushed again?). The only reason I had the system flushed out before was because it wasn't heating very well. I did fill it up to the proper cold level and drove it today and it didn't act up at all. I'm thinking about doing the thermostat just because I have never done it since I have had it. I may add more coolant just in case it is the air in the upper hose too. Anymore input would be great and thanks for the responses so far!
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bedrck46
Replace T/Stat with a Motorcraft Stat.
BAD RONALD
Full Access Members
Haven't yet but I am going to try this complete flush:
2000 Ford Expedition - Coolant System Flush with Degas Bottle - Clean and Thorough - YouTube
AF the color you describe needs to be replaced. Good a place as any to start with cooling problems.
2000 Ford Expedition - Coolant System Flush with Degas Bottle - Clean and Thorough - YouTube
AF the color you describe needs to be replaced. Good a place as any to start with cooling problems.
BAD RONALD
Full Access Members
Has the coolant level dropped more than once? If you are losing coolant there's a crack or leak someplace.
I haven't noticed any coolant level drop before I put more in yesterday but I know it hasn't dropped since then and I checked it twice. I'm going to plan on changing the thermostat and replacing the coolant again. Any more input will be appreciated!
Just checked the coolant level after adding some yesterday and it is where it should be after sitting all night.......that probably eliminates the idea of a possible leak. I'll take anymore input on this....Thanks!
FordandPolaris
Full Access Members
Some leaks only open up when they are under pressure. Check it again after driving some and then letting the truck cool to truly eliminate the possibility of a leak.
Did a water pump and thermostat on it today.......my local Ford shop said they have seen the water pump rust and fall apart on the inside so I decided to get the thermostat done on too. The water pump looked good when it came off but put the new one on anyway.....when the thermostat was removed it was found to be stuck open.....I'm thinking this is the culprit. New thermostat was installed and new Yellow Motorcraft gold coolant. I'll run it a few days and see how it goes. Thanks for all the responses!
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bedrck46
Thanks for the update
stamp11127
Full Access Members
A stuck t-stat doesn't cause your original problem. It is just a flow restrictor when cold.
BAD RONALD
Full Access Members
...under pressure and hot. Esp if the missing coolant is disappearing out of the tailpipe. A fairly long test drive is in order.
I don't think that there ever was coolant missing (Although I'm still not completely sure it was put back at the correct level in the first place after the system flush)....after I checked the level initially and added some the correct level hasn't changed. A longer drive to test it out is planned for the weekend. Hopefully with the new sensor, water pump, thermostat and coolant this problem has been cured.....if not....I'm not sure what 's next.
I thought about the coolant going out the exhaust too or other head gasket related things but haven't found anything pointing to that......no coolant in the oil or no sweet smell in the exhaust either. I was also told that if the truck is cold and you take the cap off the coolant tank and have someone turn it over while watching the tank to see if there is a bunch of back pressure would indicate a head gasket as well......it didn't do that either. A compression test hasn't been done though.......I would think there would be other issues if the gasket was the case. I appreciate the responses so far and welcome anymore input.
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