my car is right hand drive. there is a pipe from the back of the engine that goes into the passenger compartment. just before disappearing behind the firewall, the pipe is cracked and leaking. is this pipe for the cooling system its for passenger compartment heating? since i cannot find a replacement, what happens if i block it on the engine side?

 

This sounds like the black plastic bulkhead fitting in the heater hose - this is a common failure. Repair is neither difficult nor expensive.

The fitting is readily available for about $10 US. Use Google (or other search engine) to look for part number 220 832 0015.

To change it (as usual, these are for LHD cars - you should have experience in adapting to RHD):
- Lift the hood (bonnet).
- Remove both wiper arms - pull off plastic caps, use 15mm tool. Remove and don't lose the small plastic rings found on each of the wiper studs. If the stud closest to the center of the windshield turns freely with the nut, use an Allen wrench (hex) in the end of the stud to hold it.
- Lift hood to the vertical position. Pull down slightly, push the small square metal arm on the driver's hood hinge, and lift the hood more vertical. Go to the passenger side, push the square on that hinge, lift the hood fully vertical. It is now safely locked in place.
- Find the four plastic Phillips screws holding the front edge of the black plastic rain shield at the back of the engine compartment. Back the screw almost all the way out, and gently pry/pull out the round plastic rivet that the screws were holding. Don't drop them, or the slip on nutplates that they screw into - they are plastic, and difficult to retrieve.
- Carefully remove the rain shield. It will be held in place by a ridge near the back of the shield that snaps into a groove at the base of the windshield. If you have the plastic wedge/pry bar tools, you can use those to go up under the lower edge of the shield and up to the windshield near one end. Pull up on the upper edge and pry up between the shield and windshield. Be very careful if you use metal tools to avoid hitting or pressing hard on the windshield! Work the end out of the rubber piece on the fender edge and carefully pull up along the top edge to snap the shield out of the windshield groove.
- Unplug the wiper electrical connector.
- Use a 24mm socket to remove the four nuts and one washer holding the wiper assembly, and lift it out. Try to avoid hitting the windshield, and also avoid turning the horizontal tooth wheel under the wiper assembly. This is adjustable to hold the front of the assembly in the proper position.
- Pull the rubber seal off that runs across the engine compartment.
- Use an 8mm tool to remove the two small screws at each end of the central removable section of the forward firewall. Either cut the wire ties holding the wire harness to the removable piece, or pry the metal rings from the ends of the brackets holding the wire ties, so that you can pull the removable section out.
- You now have good access to both sides of the leaking fitting. Squeeze and move the hose clamps down the hoses away from the fitting on all three hoses. Remove the hoses -
there will be very little coolant loss. Rotate the fitting and pull it out of the bulkhead. The crack will be virtually invisible.
- Check the new fitting to make sure that there is o molding flash in the slots that will make it difficult to install.
- Clean out any leaves, mouse nests, and other trash while you have access.
- Reverse the above steps.
- If you removed the metal rings from the wire harness supports, use a socket that fits them to help push them back on.
- Don't forget to plug the wipers back in.
- The upper end of the rain shield will snap into the groove with hand pressure.
- Lower the hood to the normal lifted position before installing the wiper arms. Press the metal squares to release the hinges.
- Don't forget to install the small plastic rings on the studs. On left-hand drive cars, there is a small line on the right (passenger) side of the windshield that shows the position of the parked wiper arm I assume (but do not know) that there may be a similar line for the RHD cars. Loosely install both parts of the arm to the studs, then move the arm to the proper position by letting it rotate on the center wiper stud. This will take several tries. The left blade goes parallel with the right blade.
- Check and correct the coolant level, and repeat a couple of times over the next few trips.