Temp/Heater Questions

[BROOKLYN 3]

I recently acquired an 89 325i. Today I checked all the fluids, tires, and general health and all seemed well, so I decided to take a road trip. As I was leaving town I got stuck in Holland tunnel traffic. I was in it for about 45 minutes, and after about 25 minutes of idle time I noticed the temp going up. It didn't go into the red, but was close. I tried turning the heat to high, but it wasn't hot. As I started to move the temp started to go down and the heat got hot again. Now as I was moving again the heat was set to windshield and it got fogged up with condensation so I set it to the floor and opened the windows to clear things up. Once I was on the highway for a while the temp went down to just below half and I was able to us windshield heat without condensation.

My two questions are:

1. Does the temp in these cars usually go up in traffic?

2. What would cause the condensation in my heater ducts?


Thanks in advance.

[quikveedb2]

1. Does the temp in these cars usually go up in traffic? No, check your fan clutch.

[IP2GSR]

I would bet you have two separate problems.

The engine temp raising in traffic is due to low air flow through the rad which is probably from a bad fan clutch. The other option is a rad that is plugged and does not flow.

The cool temp from the heater is from a bad header valve that does not allow hot coolant into the heater core or a plugged heater core.

Good luck

[BROOKLYN 3]

Thanks for the quick responses. I'll check the fan clutch tomorrow. I don't know much about heater cores, but I'll search for a test for it tomorrow as well. Thanks again!