Your question is incomplete. You asked a question that is like, "Where is the hole in the Swiss cheese?". There are usually several holes and each hole has a specific item or loom of items running through it. For example, the speedometer cable may have a hole in the firewall for itself or the A/C lines have holes in the firewall for their passage. BETTER QUESTION: WHERE IS THE HOLE IN THE FIREWALL FOR THE _________________?
If you are talking about a 1998-2005 Passat there is a bleed hole in the cooling system for this purpose. The heater coolant lines pass through the second firewall remove the clamps on the lines and pull them toward the front of the car about an inch. One of the lines has a little hole for bleeding the system.
There are several firewall holes.The firewall is the wall that divides the engine from the passanger compartment.Under the windshield.
On a 2002 Lincoln LS : The engine coolant reservoir is in the engine compartment , on the drivers side , by the firewall ( you can see the cap on the reservoir through a hole in some kind of trim according to a drawing I was looking at )
There should be a location where you can go through the firewall where other wires are already there. Piggy back on that hole. If not then just drill a hole through the firewall, being very careful not to drill into any wiring or components. Insert a rubber grommet in the hole to protect the wire, and then the wire.
I was looking at a picture in the 2004 Lincoln LS owners manual and it shows that the engine coolant reservoir is located on the drivers side of the engine compartment next to the firewall ( you can see the cap for the reservoir through a hole in some kind of panel )
If you cant find an openening large enough then you can always drill a hole and place a grommet in the hole and then run the wire through the grommet. Hope this helps.
there is a little hole right under the hood next to the driver side door
On a 2002 Lincoln LS : The degas bottle ( engine coolant reservoir with the pressure cap / radiator cap screwed on the top ) is located in the engine compartment , near the firewall , on the drivers side of the engine compartment ( you will see the " cap " through a hole in a piece of " trim "
On a 2002 Lincoln LS : The engine coolant reservoir has the pressure cap / radiator cap screwed on top of it , so it is called a degas bottle * it is located in the engine compartment , on the drivers side , near the firewall ( there is a hole through the " trim " to gain access to the cap )
If you can't find a safe way to snake a wire through the firewall, try going in from under the front or back seat area. Drill a small hole and use a tight fitting rubber grommet. Who says it has to go through the firewall anyway.
Drill a hole and then insulate the hole with a rubber washer so the cable doesn't chafe on the jagged hole.
On a 2000 Lincoln LS : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap * the engine coolant reservoir is in the engine compartment , on the drivers side of the engine compartment , next to the firewall , you can see the cap through a hole in the " trim "
If you need a hole to run wiring through then follow wiring to an existing hole and work the new wire through. If it is a hole that needs to be repaired, then small holes can be filled with a silicon to waterproof them.
On a 2002 Lincoln LS : The engine coolant reservoir is in the engine compartment , on the drivers side of the engine compartment , next to the firewall . According to a drawing I was looking at there is some kind of trim piece over the top of it , but the trim piece has a hole in it to gain access to the engine coolant reservoir cap
I'm not a mechanic / technician but I BELIEVE the degas bottle is another term for the engine coolant reservoir In a Lincoln LS the engine coolant reservoir is in the engine compartment , on the drivers side , near the firewall ( you should be able to see the cap on the reservoir through a hole in some kind of trim )
On a 2002 Lincoln LS , the engine coolant reservoir is in the engine compartment , on the drivers side , near the firewall ( from a drawing I was looking at you should be able to see the cap on it through a hole in some kind of trim )
look right above your brake pedal underneath the steering column.
chances are you have a cracked heater coil
small hole in the tank or in lines ..even rusted lines
check for rubber grommets in the firewall that already have something protruding through them if not then you'll have to drill a hole.do not run an electrical wire through bare metal hole because it can cause a short.get some grommets to put in the hole first then run your wire
You'll need to locate a suitable location in the firewall to drill a hole through large enough for the cables to fit through. Drill the hole. Install a rubber grommet around the hole to protect the cables from being cut by the metal. Then you run the cables through. you may want to use rtv sealant to make sure the firewall seals off the engine compartment from the cab.