Car Heaters

Unlike most other BMWs the Z3 does not have an electric water pump for the heater. This means it is sensitve to air locks in the system. Eventuly these should clear themselves. Mine took a week to come back to full operation after replacing the coolent and bleading the system as per the instructions.

I think the overdrive observation is just a red herring and the heater will work once the engine exceeds about 1500 rpm for a while.

Make sure the coolent and oil levels are correct and try holding the car in a lower gear for a minute or so at 4000-5000 rpm while driving. This should force the air out of the system.

unit could be low of refridgent,or valve for heater not closing complety There can be other problems, but these twowould be the ones i would start with.

Need more info like, is the blower working or not, is the air coming out cold or warm when it should be hot, is the air not coming out where it should be.

Bad selector? vacuum leak at engine or vacuum motors under dash

because u pooped in it

Make sure you didn't knock off the sending unit wire.

You have a vacuum leak. When the a/c controls don't get any vacuum, it defaults to the defrost position. Check and make sure someone didn't accidentally disconnect the vacuum hose with their feet. Look under the dashboard on the passenger side.

I'm in the same boat: Try reading all pages on these links:

http://townhall-talk.edmunds.com/direct/view/.f15850c/0

http://forums.automobilemag.com/70/6248778/toyota/2002-toyota-highlander-problems/index.html

this one has photos how to do the repair:

http://www.tundrasolutions.com/forums/highlander/32217-heater-quit-sort-of/

My first guess would be that your thermostat is stuck open,not giving the coolant a chance to warm up (the warm air comes from the coolant or water in the engine being circulated through the heater core)My next suspect would be the vents that open and close to send either warm or cool air into the vehicle are not opening and closing as they should. This could either be a vacuum or electrical problem depending on the vehicle. Good luck, mannsvillain

the heater core could be pluged or the heater control valve is stuck closed

ck the two hoses after engine is warmed up.Both should be hot if control valve is working. If valve is working remove hoses at heater core very carefull and use garten hose and go from one to the other until water is clear hook up and try again

sounds like your heater core is plugged up with gunk install a new one

I just read an article that talked about "burping" your cooling system to get the air out of it. Basically, you pop the hood, take the radiator cap off (cold engine only), start the engine and rev it a bit. Not too high, just enough to circulate the coolant. You can have someone else rev the engine while you watch the coolant flow in the radiator. While the engine is running/being revved add coolant to the filler tank (not the radiator directly). Do this for several minutes and watch for "burps" and "gurgles" of air. Be careful because they might belch out of the radiator unexpectedly and splash over a bit.

The heater valve may not be engaging or the heater core may be blocked.

Heaters come on and off the keep the room at a particular temperature. If you don't want it to come on and off turn the switch to off. Don't keep it on auto or fan.

Go to www.the12volt.com they have free wiring diagrams.

Low on coolant.

Stuck open thermostat.

Poor circulation (plugged heater core).

Check the coolant level Could be a bad thermostat Could be a bad temperature sensor (climate control system)

Look down to the right of the gas pedal where the console is. I believe you'll see a "door" that moves when you move the dial through the vent settings. Sometimes these will pop out of place and all you need to do is set it back up.

Here are a couple of basic things to check: 1-Make sure the coolant level is correct in your radiator and overflow reservoir. 2-Make certain the thermostat (in the water outlet housing) is in good working order. This should be replaced every 24 months because it is cheap/easy insurance that your car's cooling system will run well. Also, make sure that the thermostat in the car is the correct one (with regard to temp) stated in the manual. 3-Are the hoses leading to the heater core (in the engine bay) swollen/damaged/old? 4-Is the actuator arm/servo/solenoid for the heater core bypass functioning correctly? Basically, when you "turn on" the heater, something has to physically open/close the coolant bypass valve to the heater core to allow warm/hot coolant to flow into the heater core (under your dashboard). If this process is electronically controlled, it is possible that it is failing to open that valve some times. If it is a mechanically controlled process, the heater bypass may be obstructed. 5-Heater core may need replacing. If the heater core has a lot of build-up in it, the coolant will not circulate as easily as it should which can cause the heater to not function properly. There is probably more to check, but its nearly 3am and Im not thinking clear enough to proceed any further. Good luck.

on the fire wall on the passenger side there will be 2 hoses same size right beside eachother. dissconect each of the hoses and then connect them together with a smaller diameter hose between the two of them. DO NOT CONSIDER THIS A PERMENAT FIX! As answered correctly about disconnecting the two hoses from the heater core on the firewall, and joining them together, they are not always the same size like in my 94' Cavalier, just keep in mind reducer fittings. I used a 5/8" to 1/2" copper fitting as that was the I.D. of the two hoses and i recomend using hose clamps to. Who answered origgionally is very correct on Bypassing. It is a quick fix but get it fixed before winter.
Disconnect the two hoses that go to the heater core on the firewall and connect them together or if one is long enough, run it to where the other hose connects to the engine. If your heater core is leaking, you can use liquid glass to seal it. There are several different brands available, it is the radiator stop leak that is a clear liquid with copper colored flakes in the bottom of the bottle. Follow the directions and it will probably fix the problem. It works most of the time.

Check the fuses.

location of heater control valve on 2005 mercury marguis ?