Overheating!!!

Greetings all,

My 1.8L 2001 Sentra GXE was overheating, I changed the radiator. A couple weeks later it starting doing it again and I added colant to the radiator (was full before) and it has been fine. Now, a month or so later it is doing it again (when idling in warm weather). I added coolant again and so far it has been fine. I don't see any liquid on the floor. Any suggestions?

did you use pure coolant, or the 50/50 mix?

well obviously we got a leak if you dont see anything on the ground check oil level & condition.how much coolant are we talking about over the weeks/month??if oil looks ok see if you can check when system is under pressure. could be a small leak & evaporating on hot engine/exhaust

or... could be a cracked head or blown head gasket. New engines are made of aluminum when your car overheats even once it could crack the head or blown the head gasket. Old carb cars with iorn blocks and heads could overheat no problem but not aluminum. Place a peice of card board on the tail pipe after car is warmed up. If it becomes moist or wet that means your car might be leaking coolant into the engine.

or water is a byproduct of combustion/catalyzation..... moisture doesnt tell you a thing, white smoke is coolant, usually noticed on startup if youve let it sit for a day or so

if you can, take out your thermostat and put it in some hot water and see around temp it opens. if your thermostat stays stuck closed it can make the car overheat because it blocks the coolant from entering the engine past a certain temp

I would not go by the cardboard idea. The exhaust will almost always emit some moisture.

You could just have a pinhole leak in the radiator or other area. If you are concerned about a cracked head, that would usually become evident in the coolant. If you take of the cap (remove when car is cool please) and there is a black/brown foam collected on the top, you may have a problem. If there is just green foam, then you probably do not have a serious worry.

It would also be helpful to know how much coolant you are adding and just how hot the car is getting (is the temp gauge pinned hot? or is it just running warmer than normal). I think a good rule of thumb is to do a complete service and have the system flushed and the thermostat replaced.

the coolant will also smell like exhaust/fuel if you have a cracked head

i say check the head gasket. it could be a real small leak that is going into a cylinder ( probably #3). take out plugs and shine a light into the hole. the one that is shiny is where the leak is. it happened to me. it is very common i am told.

common is not quite the most accurate word, id use "guaranteed eventually" lol