I have a 4 cylinder Jeep Wrangler YJ that has been having some issues. I bought this Jeep as a fixer upper about a year back. I replaced the motor, and the transmission. As of recently I also fixed my heater, it was the blower plug on the passenger side of the heater box, it had a dirt dauber nest in it. I have had a problem for about six months now; I just cant figure it out. My heat gauge rises to just before the red over heating section of the gauge then it will fall below 210. It rises to the large mark just past 210 and then falls to the large mark just below 210. It will then go to back up to 210 and stay there for thirty minuets or so the then process repeats. My oil gauge shoots all the way over every time I start the Jeep and stays there, however all my other gauges work just fine. I changed the thermostat twice thinking the first new one I put in might have been damaged. I got the same result both times. My water pump is circulating; I know this because I can see the level of the water drop when the jeep gets to running temp. That should also mean the thermostat is opening I would think. There are not any leaks around the water pump, and the coolant level is the same; not loosing any. Also, I noticed tonight that my tail pipe has steam coming from it, and a water pool was building up behind the Jeep just under the tail pipe. Its not pouring just condensation from the steam heating the ground; it is cold out side. I felt it and could not feel any oil. I also smelt it; it did not have any gassy or coolant orders that I could tell. The steam is white in color and after the jeep warms up it becomes less, but never stopped. When gas was applied it would increase. I have not had any loss in power, I changed the oil about a month ago and there was not any water in the oil. Any suggestions and help I could get would be appreciated. Thank you for reading my long drawn out post and helping a fellow Jeeper.
If there is no water (coolant) in the oil it sounds like the water vapor out of the tail pipe is normal. That means you have a tight exhaust system. The condensation is coming out normally through the tail pipe. The fluctuation in the temp. is probably due to air in the system. When you change the coolant you have to "burp" the system allowing most of the air out. Eventually the air will make it's way out on it's own. But, after six months you might want to take the cap off of the radiator, run it up to temp. and the air will push out. Close it up and refill the expansion tank. The oil gauge is due to the sending unit. They don't last. Replace it and your problem should be solved.
Thanks for the help I have been racking my brain over this. I am going to try to burp the system like you were saying today and double check the oil dip stick for watter. I will let you know the results.
I checked the oil and it has no water in the oil. I have not used any oil in a month since my last oil change either. I burped the radiator by taking the cap off running the motor till it heated up to running temp and the circulation kicked in, the coolant level dropped so I put a little more in, waited till the circulation stopped and started again, filled the expansion tank, and put the cap back on. I still have the same problem. I wonder if I could take the radiator cap off, and put my digital thermometer from my smoker in the coolant to see exactly what temp the thermostat is opening up at and what max temp I am running at?
I am not sure had it done by a mechanic, after I got it back from them all the gauges worked very good for about six months. Then the oil gauge started shooting straight over as far as it would go. I read online that it happens all the time because of crappie sending units so I did not worry about it to much. The rest of the gauges worked. Well, until the heat gauge started messing up about three weeks later. Every thing I found online said it was the thermostat, ruled that out, and then burped it. Still doing the same thing. I am going to read the temp on coolant with a digital thermometer in the morning. I will tell you guys what it reads. If any one has any ideas of things I can do shoot them at me and I will try it out while it is cold in the morning. I will check this before I work on it. Thanks for the help I have gotten so far, I am sure we will track this thing down and fix it.
seeing as both gauges are giving you problems could indicate a wiring problem or bad ground somewhere...but....with these YJs it could just be coincidence. Replace the temp sending unit, its at the drivers side rear on head, tucked right up near the valve cover, they are only about $10. I replaced two of them before I got on that read near normal, this one runs about 190-210, last one never got above 150.
2013 WRANGLER SPORT 2 DR., V-6 ,AUTO,HARD TOP
(Sold)1994 Jeep Wrangler 2.5L, Bestop top
/w steel half door and slider windows
5 speed, 2.5" lift, 31" tires,rack lights