Maserati Heater Core/Heater Hose Re-Route


Here is a step by step process to give you breathing room on a costly repair that needs to be done on your vehicle. I first published this on to help all Maserati owners who were facing this problem. It’s a safe effective way to deal with any coolant loss inside the cabin of the Maserati through the heater core.

First you’ll need some supplies from your local auto parts store. It doesn’t matter which one.  Here’s what you’ll need.

  • 3′ section of 3/4″ heater hose.
  • (2) 3/4″ hose joiners or couplers
  • (4) hose clamps to fit 3/4″ hoses
  • Extended life coolant preferably a good brand compatiable to be mixed with other brands of coolant.

The entire process should take maybe an hour.  The first part of this process is to remove all of the trim pieces around the engine compartment just to give you room to work with. Usually in this process I replace all of the trim screws with stainless steel screws and matching washers. In my opinion it gives it all a better look when it’s put back together. Additionally, you can use a small flat blade screw driver underneath the hood strut clamps in order to pull it up enough to detach the ball and socket.

After removing the trim pieces, you will be looking directly back at the fire wall of the car. The heater lines come out of the firewall slightly off-center to the driver’s side of the car. In the UK that would be the passenger side.  You are looking for these:





The first picture shows the line coming from the firewall with a hose clamp on it. This is the top line. The second line however, which is directly below it in the photo actually follows the back of the fire wall behind the intake manifold, and 90 degrees right underneath the coolant reservoir. That’s what I am showing in the second/third picture. It is also why you will need 3′ of coolant hose. Essentially what you will be doing is disconnecting both of those hose clamps, and running a line of hose with a joiner to connect all of the heater hose together. When you are finished the hardlines of the heater lines will be disconnected and left open. (You can use electrical tape and wrap around both openings or find some end caps as well. You’ll want to blow those lines out with compressed air before you do so.)

Before I forget make sure you have a catch pan underneath the car to catch the coolant that will be lost when you disconnect these heater hoses.

Here are some more photos:

This is the top heater line again coming out of the firewall, as you can see it’s almost directly behind the driver’s side Valve cover. It’s a hardline that leaves and immediately connects to a rubber heater hose:





Here is the second line following the firewall down towards the passenger side before turning, and connecting to a rubber heater hose.




So now, you’ll take the 3 foot length of hose and connect both joiners to it like this (they can be plastic or metal joiners it doesn’t matter):



You will then loosen both hose clamps going to the car’s hard lines, and connect them to this hose and joiners you just made. If you need to loosen the rubber lines, as they do get stuck from the hot/cold cycles use a set of open pliers, and rotate the hose back and forth to loosen it’s grip. You can also attempt to stick a flat blade screw driver between the hardline and rubber line to pry it up. When you have the lines connected they will look like this:



You will want to loop the hose on the driver’s side fire wall around so the heater hose isn’t crimped like the lines show in the first photo above. Next tuck the heater hose down like this so it’s out of the way:



After this last step, you are finished and can re-assemble all of your trim pieces.



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