My car is overheating and I have no heat - any ideas what's wrong?

Your coolant is either low or leaking (cabin heat comes from blowing air across hot antifreeze in the heater core). Worst case scenario, your head gasket is blown. If your car isn’t running poorly, it may still be cracked or leaking into the head or down the side of the block. Best case, you just need to top off your coolant.

So, step one, check your coolant level. Fill it up and pay attention to it for the next few days. If it starts disappearing, check for a sweet smell (very similar to pancakes, actually) from your exhaust. That smell and/or thick white smoke indicates that you’re burning coolant in the cylinders, which means your head gasket is toast. If that’s the case, stop driving to avoid any further damage to the head and have it checked by a mechanic. If it overheats too much or too often, the head can warp and resurfacing is really expensive, let alone the labor involved in removing and reinstalling it.

Also, check the passenger side floorboard. If there’s coolant inside the car, you probably have a busted heater core.

Joey is right. If you continue to drive and overheat, you can blow the head gasket. In a car like that, the cost to replace it will be more then your car is worth.

First things first, check the coolant. Then tell us. Then we’ll give you another suggestion.

yeah my carl likes to over-heat when it sits in idle for too long! Needless to say traffic jams a pretty stressful! I have no clue what’s wrong with mine either but I know it isn’t the coolant. It only happens on rare occasions so no auto-body place has been able to tell me. Could it be a problem with the computer chip in the car? Sorry to steal your question hellokitty this just got me thinking maybe someone in here had an answer…

I agree with the above. Get it looked at before it’s too late. I had a similar problem and it was my thermostat.

madcapper, have you had your thermostat replaced? That’s the first thing I would do because it’s such a cheap part. Even in a newer car, the coolant flow is based on functioning of mechanical parts and not electronic parts. I would guess that it’s not the computer unless you’ve got a real crazy car.

(Just a tip, when cars would overheat at the shop, we would keep running them and spray the front radiator from the hose)

Sometimes I would see stuff like that in cars that have two fans and one had gone bad (and wouldn’t spin). The car would be fine most of the time but when it sits, it would overheat.

@madcapper, also make sure your radiator fan is coming on. If you let the car sit, the fan will come on once it reaches operating temperature and turn back off after a minute or two. If your car only overheats when it’s sitting still, the fan may not be working, but the airflow created by moving is doing enough to cool the radiator.

I agree with joey, if you really want to see if air flow is the problem, you could put a shop fan (it’s got to be something decently powerful) on the front grill of your car while you idle it to see if it overheats. If it doesn’t, that lowers down your possible problems immensely.

(and of course clear any debris from in between the fan and the radiator)

thanks bodyhead and joey those are both great suggestions! I am not a car guy so I didn’t know what to do but I will for sure look in to both of those ASAP!

i go with replacing thermostat.

Low antifreeze level or thermostat.

I’m having the same problem with it overheating and no heat. I did all the diagnostics to see if it was a blown head gasket but nothing points to that. It does smell really badly of burnt antifreeze though and it overheats bad. I changed the thermostat last week and the waterpump less than a year ago but it still has problems with overheating. What else might be wrong?

Check your heater hoses going to your heater core by the firewall. If one is hot and the other is cool your heater is plugged up. This does not mean the heater core needs to be replaced. It may be flushed out and you will get good heat again. This service will need to be done by a qualified shop. Reverse flushing the heater core needs to be flushed with water and air pressure. If both heater hoses are hot it may in the air distribution box which may be a cable or actuator. Unfortunately there is no easy answer, get it checked before the cold weather hits because then its tough to get into a shop. I hope this helps. www.triangleradiator.net