Expert: Sean Halliday - 5/1/2007

Question
I just got a 1995 Nissan Altima GXE. My "Check Engine" light just came on today and I need to know how to check the codes. The owners manual is MIA so I'm left with having to go to the dealer and paying out a lot of money just to find out it's probably nothing serious. Since my light came on, my engine has been idling around so erratic, one second it's at 1000 rpm's and the next it's barely running at 450, then back up to a 1000 the next second. I smell coolant and there's very thin wisps of smoke coming from the between the fan and the radiator. All this started early Sunday evening with the car overheating, so I pulled over and popped my hood to welcome a ton of smoke and coolant all over my engine. The radiator cap looked like someone had just sat it in place but never turned it to tighten it on and the overflow had about a cup of coolant in it. Mind you, my fan was not kicking on during any of this. About an hour later I took it for a drive to see if I could here anything more but all it seemed to do was run very rough. I stopped with the car still running and lifted my hood again to see if I could hear, smell or otherwise find anything out of place, about 3 minutes into it, my fan kicked on, go figure. Saturday Morning, I had some errands to run so I went up the highway to take car of them, on my way back down the highway, I had no choice but to run over a semi's tire re-tread laying on the ground. Afterward, my car started running really rough and idling very weird (as mentioned before) but now my fan is kicking on when it seems it should be (like all is good with it). I should mention that I had a little 50/50 left over so I put in the radiator when it overheated Sunday evening, then drove to a water source (about a half mile) and filled the rest up with plain hot (so as to not destroy my radiator) tap water.

Now I'm at a loss. My "Check engine" light came on today when I was going back out for my next run of errands and I have no way to check them.

Any ideas?

P. S. Sorry for making a novel out of this, I just thought I would give as much detailed info as possible in order to be helpful.

Answer
Your car is in the area of OBD1  or OBD2.(Most cars changed in 1995 to OBD2)  I need to know which it is and it will say under the hood on the label.If its OBD2 you need a scanner which plugs in under the dash these cost about 150$.at any parts store but if its OBD1 then let me know and i will tell you how to read the code.As for the coolant and overheating,if the cap was loose it will dump a lot of coolant but if its a leak or blown head gasket then its more serious.The only way to tell is fill the radiator and drive it and if it is leaking through the head then the coolant will be gone and the symptoms you say will be ,rough idle ,,overheating and loss of coolant rapidly through the tail pipe.Your fan will not work if the radiator is empty as it is activated by temp of the coolant.