Car Overheats: Need Help Troubleshooting

[surechap]

My 1997 318ti is overheating, I think I have an electrical failure; but all fuses are fine.

1.)Coolant level is extremely low. I don't know how it could get that low in just a few months, must be a leak.

2.)Radiator Fan does not turn on, but the car temp guage still stays in the middle I'm not sure how? Even when I turn on the AC the radiator fan will still not blow.

3.)AC is dead ,it only blows hot air now.

Why is my car overheating? I'll add some more coolant, but I'm not sure why my AC and radiator fan will go out at the same time. Please help diagnose the problem, I think it's electrical.

[Dr Shuffles]

First you say the car overheats, then you say the temp gauge stays in the middle. So which is it?

If the fan doesn't spin, the AC condenser might have a hard time dumping heat into the air. So that might account for the AC.

Start with the known problems: find the coolant leak and fix that.

[surechap]

Originally Posted by Dr Shuffles

First you say the car overheats, then you say the temp gauge stays in the middle. So which is it?

If the fan doesn't spin, the AC condenser might have a hard time dumping heat into the air. So that might account for the AC.

Start with the known problems: find the coolant leak and fix that.

The radiator fan will not turn on no matter how hot the car gets. I idled the car and watched the temp gauge to see if it'll overheat. It slowly rises till it reaches the exact middle then stays there for quite a while. This time I decided to wait a little longer, sure enough the car begins to overheat. I remember something about the temperature gauge being idiot proof I guess this is why it stays in the middle for so long.

Is it possible that the radiator fan was broken for a while causing the coolant to evaporate?

I double checked the AC, it kind of blows cold. When I stopped or idle for long time it beings to blow hot air. This confuses me, I was getting ice cold AC before.

Which fuse goes to the radiator fan? I over heated the car to almost RED, should I be worried?

[Dr Shuffles]

The AC behavior that you describe is consistent with my theory. When the car is moving, there's air moving over the condenser coils, which would partly make up for the lack of a fan. So if I'm right, fixing the fan will fix the AC.

Search this forum for a diagram of the fuse box, it's out there somewhere. Then check the relevant fuses and relays.

And obviously, top off the coolant if you haven't already.

[jca]

Originally Posted by surechap

The radiator fan will not turn on no matter how hot the car gets. I idled the car and watched the temp gauge to see if it'll overheat. It slowly rises till it reaches the exact middle then stays there for quite a while. This time I decided to wait a little longer, sure enough the car begins to overheat. I remember something about the temperature gauge being idiot proof I guess this is why it stays in the middle for so long.

Is it possible that the radiator fan was broken for a while causing the coolant to evaporate?

I double checked the AC, it kind of blows cold. When I stopped or idle for long time it beings to blow hot air. This confuses me, I was getting ice cold AC before.

Which fuse goes to the radiator fan? I over heated the car to almost RED, should I be worried?

Worrying won't help, but you probably shortened the life of your head gasket when the car overheated, "almost to the red." Only time will tell. Just find and fix the overheating problem and press on. Overheating is the main killer of ti engines.

[surechap]

Finally, I got it fixed. Apparently, it wasn't the fuses or relays; the cheap after market plugs from the aftermarket radiator fan were falling apart. I cleaned out the pins, blew out the broken plastic pieces and plugged the fan back in. Sure enough it works again .

Personal thanks to Dr. Shuffles and Jca

[Dr Shuffles]

Glad to hear it. So is the AC working now?

[surechap]

Originally Posted by Dr Shuffles

Glad to hear it. So is the AC working now?

Yes, everything is working. I do have this one problem though, the egr valve is pinging. I discussed this in another thread, plus a few missing vacuum hoses.

[CosTick]

im having the same problem, i thought it to be a problem with the cooling system, air bubble, etc... but purging that and topping it off doesnt seem to help, the car only seems to overheat on hot days in slow traffic, on the freeway its fine, i cant tell if my fan is kicking on or not, ever. i also have issues with my a/c when the vehicle isnt moving. does it sound consistent with fuse or fan issues?

[Dr Shuffles]

Yeah, it seems consistent with a fan problem. The engine radiator and the AC condenser are right against each other, so if there's no air moving then both of them will be unable to shed heat.

Pop the hood, start the engine, turn on the AC. The fan should be blowing at that point - if not, then there's your problem.

[CosTick]

thanks Doc, ill give it a try.