I have a 2003 X type with 86,000 miles. The car runs fine, but I just noticed an issue with the heat. It took longer than usual to feel heat coming from the vents, it just blew cold air for a good 10-15 minutes. But once I got up to 65 miles an hour the heat worked fine. Then when I got back into town and drove slower, the car started blowing cold air again. I just had the radiator flushed and filled, and I'm going to check the fluid level in the morning. I was just wondering if anyone had an idea what the problem might be, and how I should handle it.

 

jrm, I would bet you are going to find the fluid level low. If this is the case, top of the tank again and then see how things are for you. IT is possible that following the flush you have a new leak and what you are seeing is that the tank is getting low and the coolant system is keeping the fluid in the engine and not allowing things to make it to the heater core.

 

I have the same situation, but not as harsh. It seems my car doesn't get warm or cold in the summer, for quite a while. My radiator is full all the time so it is not that. IMHO I feel it is the cooling heating fan which I think is not blowing hard enough to circulate the cold or warm air in the car. The other night I took a ride out to the Berkshires to visit some friends. It is about 40 miles one way all interstate. At 75mph there is plenty of heat, however when I got to Lee, Ma and in town and had to slow down, so did the heat, It was 15 degrees that nite and I wasn't cold, but I wasn't warm either. I am making an assumption that the cooling fan also circulates the heat in the winter, whether this is correct let me know. I noticed the control module for the fan is in a spot that is easy to get to, I am thinking about having this module replaced and see if there is any difference.

 

Adam, yes, the hot coolant from the engine flows through the dash even in the summer. But, what allows the air to be cooled is the fact that the air is diverted around the hot coils and only on to the cooling coils. hence only the cold air. As for your situation, you may want to look at the water pump. IT is possible that what you are experiencing is a lack of water flow at low RPMs, but with the motor up at speed (ie, 2,500 RPM), the pump can develop enough pressure to push the coolant through the dash. Keep in mind that it is a long hose between the engine and the dash where the engine is a much easier loop to make it through.

 

Thanks this makes a lot of sense. After I made this post I met a man who also has an X type, found out he lives in my area. Anyway we were talking about various things concerning the car, and has the same situation with the heat and AC, low RPM AC not very cold, high RPM cold, heat low RPM not very warm, high RPM lots of heat. Interesting enough the car never runs hot even when it is 90 degrees plus and stuck in traffic, the needle is always dead center and never goes any higher or lower, except after you turn it off and the engine cools down. I also noticed it takes a while for the car to heat up to operating temp. This could be connected with the pump. Does your heater take a few minutes to come on after you start it when it is cold? My MB did this and it was made this way so the passenger wouldn't get a blast of cold air in the winter.

 

Adam, yes, my heater will remain on a slow speed setting (when it auto) for a little bit to allow the motor to start to come up to temp. The only time it doesn't do this is when you kick on the defrost or you have the heater controls in manual mode.

 

Thanks to all for your advice. It turned out to be that two of the connections on the overflow reservoir were just about broken off and it was leaking once the engine got warm. It was confusing me because the engine never had antifreeze sprayed on it, and I never got steam rising from the engine, so I couldn't figure where all the fluid was going. Turns out the leak went right down the backside of the engine, down the steering column and out under the car so it never showed up. I replaced the reservoir tank and now everything is fine.

 

jrm, what part of MD are you in. I'm down in the southern tip. If you ever need some help, let me know. I am always willing to give a wrench or two a twist and help get a car back to 100%.

 

Thanks Thermo for your help. I live in the Annapolis, MD. area and I definitely appreciate the offer of help. Same goes for me. If you want someone to lend a hand I can help.

Thanks,
jrm1111