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Cylinder Head Temperature (CHT) Sensor replacement
As I have posted in a different thread, my CHT reads about 260 during normal operation. The code reader shows that is just getting in to the "too high" range yet nothing else indicates that the truck is running hot. The coolant doesn't seem to get too hot. So that made me suspect the CHT. I have a 2003 B2300 and typically I just go to Rockauto and look up the 2.3L Ranger and get the Motorcraft part. But for this part every single aftermarket manufacturer listed a different part number for their 2003 B2300 and the 2003 2.3L Ranger, so I thought I should try to track down a Mazda OEM one.
Many of those aftermarket B2300 CHT listings would show a Mazda OEM part number ( 1FAA-18-707A ). But when I would go to any Mazda parts website, that was listed as the CHT for later vehicles like the 2005 and later Tribute. But I called a Mazda place and gave him that part # and he said he showed it was just for the Tribute, but when he looked up the 2003 B2300, it listed a part # that was no longer available (L3H518840) and that it listed 1FAA-18-707A as a replacement...the same part number I had found on Rockauto. So I ordered one of those from Mazda. But when it gets here, it is a little different. The connector on the sensor has 3 raised areas that would key the connector, and the one on the bottom is on the left side of the new part and the original has it on the right (see pic). Also the part that goes down in the engine is much longer on the original one.
Has anyone ever replaced one of these and remember if it is supposed to be long like my original one or short like the replacement one? All 4 of the aftermarket CHTs on RockAuto show the connector to be correct, but they are all short like the replacement one. One of them seems to have a "universal" connector so it doesn't have any raised area on the bottom, so I could just cut that off of the Mazda one I have. All of the ones for the Ranger also are shorter (and have the correct connector).
I went ahead and used the new one and now the ECT seems to run between 220 and 230 (instead of 245-260) which I think is a bit more believable. I put them both in boiling water and measured the resistance. The old one was exactly what the Ford factory manual says it should be at 212F (2,03 K ohms). So maybe the new one just reads cooler because its different shape??
