Were is the drain plug located on a 2007 chevy 5.3 on the passenger side of engine . is it behind the ac unit. i want to put a engine block heater in.

Well Terry...that is hard to say with the limited information provided
so I'll give you some areas to look at...listed in order of most likely area of concern.


1/
If your vehicle has a sunroof...it's drains could be plugged which may allow water to drain into the passenger compartment. To check this open the sunroof and introduce a slow stream of water to make sure the roof drains are clear and running freely.

2/
If your vehicle has a plugged front drain pan for the windshield, that may overflow into the passenger compartment. To check this area the wipers and plastic trim parts have to be removed. The fast way is to have a helper spray the windshield with a garden hose while you monitor under the dash for leaks.

3/
If the wet area is on the same side as the vehicles heater core
then the core may be leaking. You will smell the coolant and your windshield may fog up. Check by observing the core enclosure, while the engine is running and also check the radiator fluid level (while the engine is cold) as it will drop if the core is leaking. If the A/C drain pan is plugged (and if it is located in the passenger compartment) the collected condensation may overflow into the passenger compartment..

Good Luck, let us now if you are successful.

there is a a/c drain mounted in the firewall that is plugged up. you will need to clean this drain out

What drain hose? If it is for the AC, in the engine compartment on the passenger side, the is a black plastic box on the firewall where the AC / heater blower fan is. At the bottom of this box is the drain hose. The box houses the AC evaporator and when the AC is running, water condenses on the evaporator and is drained through the hose.

First call a dealer and see if is under warranty. Have you ever been sitting at a light in the summer and a car pulls up next to you and you can see water draining out from just behind the passenger front tire and in front of the front passenger seat? Most folks have and that is a clue to where that drain is, they are all pretty much in the same place.

There is a drain tube on the lower part of the firewall that is probably plugged.Normally I use a pick to dislodge debris some use coat hangers but you must be careful not to poke at too hard and cause a freon leak in the evaporator core.

small paraffin stove under the engine will help start it,but i have no idea where the heater is on the block ,i would imagine its fitted into a core plug hole about half way up the block but what side ??

Heater core is leaking.

if you hthanks pierreave one they put it close to the battery

the heater core is not under hood it is locatied behind glove box inside

The condensation drain is plugged in the heater/AC plenum, the drain is under the hood at the very bottom of the firewall on the passenger side.
PLEASE RATE THIS INFO