Gransport/4200 Radiator Replacement

Both end tanks of my radiator have been seeping coolant and progressively been getting worse since I bought the car. Additionally, the thermostat was behaving in a way that a partially stuck open thermostat would behave.

I tried to work with the independent dealer I purchased the car from but they weren’t being overally helpful. I was getting quotes of $3,600+tax to replace the radiator alone. The local Maserati dealer was a bit better at around $2,300+tax. I decided to attempt this myself. I was able to get a new radiator from an overseas supplier for around $630 shipped including taxes/etc. Coolant (two bottles of Valvoline Zerex G-48) was another $70 or so. I had the thermostat/gasket already that I purchased a long while back but never got around to installing.

This guide isn’t so much meant to be a step by step guide but some of the items I found along the way. There are some tutorials on the net for doing this job, however they tend to be for RHD/overseas cars. There are some important differences that make the US Spec cars MORE DIFFICULT to complete this job. I timed the effort I put into this job and it came out to be about 14 hours over about a week. Knowing what I know now, I think I could get this complete in under 10 hours next time (hopefully there isn’t a need for a next time though).

The differences lie mainly in the AC system. The US Spec cars have a much larger AC condenser (about the size of the radiator itself). The overseas cars have a half sized one that only covers half of the radiator. This blocks access to some of the screws necessary to detach the condenser and power steering cooler from the radiator itself.

Additionally, the larger condenser connects to the AC system on the opposite side than the smaller condenser. This means there’s a big solid pipe that runs along the bottom of the radiator/condenser stack and necessitates disconnecting the AC system! I read of people being able to snake the radiator out but I spent considerable time trying to find a way I truly believe it may not be possible (let me know if you’ve found one). With that said, I recommend before you start this you get the AC system recovered at a garage. I had a to pay a much higher fee to have a mobile mechanic come to my home to do this as the car was already in pieces.

Top Side Prep

  • Disconnect the battery
  • Remove all the engine shields in the engine bay.
  • Remove the throttle body/MAF sensor/intake pieces to get a bit more room (more details in Mass Airflow Meter Replacement).
  • Cover the intake manifold with a cloth just to prevent anything from sneaking in.
  • Open the filler cap on the coolant resevoir
  • Disconnect both fan connectors on the top and pull the wiring harness leading to them from the clips holding them to the top of the radiator
  • Remove the two upper fan shroud screws (red).
  • Loosen, but do not remove the upper radiator support bolts (green)

Bottom Side Prep

  • Raise the car safely and as high as you can. Ensure you’re using proper equipment here. If you aren’t sure of how to raise and support the car safely, don’t proceed.
  • Remove the undershield on the car as well as the front grill. The grill is attached with five torx screws.
  • Drain the coolant system by opening the petcock (red). Have a bucket ready as this is going to make a bit of a mess.
  • After the AC refrigerant has been recovered properly, disconnect the one AC fitting (green). Cap both sides of the connection off well to prevent moisture/dirt from getting in. This is the only part of the AC system that needs to be disconnected.
  • Remove the bolts holding the shroud onto the radiator (orange). There are a total of 5. Mine were luckily in good shape but I understand they can easily be rusted/stuck.
  • Next remove the fan unit screws. There are two at the bottom, and two at the top. Remove the bottom ones for now (red).
  • Remove the nut, but do not remove the bolt for the two lower radiator mounts (green).
  • Next disconnect the fan resistor. It will have two wires going into it near the bottom of the fan shroud. Once disconnected, there are also two wire holders that these go through. Each of these are ZIP tie like devices and have a little release latch on them. It’s a bit difficult to reach but I was able to release them. It probably wouldn’t be the end of the world to cut them and replace them as well. At this point it may be worthwhile to inspect the resistor and see if it needs replacing (Testing Radiator Fan Resistor).
  • There are two brackets holding the rear O2 sensor connectors on the front of the main subframe. You need to remove these. To do so, detach the connector (pull the red tab out) and undo the torx screw holding it to the frame (red). Also remove the central bolt that’s holding the wiring harnesses (green). Tuck all this away safely.
  • Next, remove both the upper and lower radiator hoses completely (red). They may be a bit tight/stuck. Gently nudge them off, or get a radiator hose tool to help loosing them. The upper hose may be easier to get from the top of the car so you may need to tackle it from that side. Also remove the small return hose (green) from the radiator.
  • With the hoses gone, you should now be able to seperate and remove the radiator fan/shroud. It may be a bit ‘stuck’ the radiator but pull gently and it should release. Carefully snake it out from the bottom of the car. Because the rad mounts are all loose, you can push that part of the assembly forward a bit to get a bit more clearance. It should slip out the bottom with a little bit of persuasion.

Bumper Removal Prep

To get to some of the screws and bolts to complete the job, it seems a bumper removal is necessary. With the half sized condenser, there is probably room to reach through the grill opening to get to these, but not in this case.

  • Remove both front wheels from the car. You will also want to remove the inner wheel liners from both. They are held on with a variety of 8mm bolts/screws and the two halves are Velcro’d together.
  • Remove the rubber cover and the two 13mm bolts holding the bumper to the bumper beam (grey)
  • Remove all the bolts (red) holding the bumper on the top side. Make special note of how many shims are under each bolt between the bumper cover/top of the front beam as you will want to return it the same way.
  • Reach in through the wheel well and remove the two bolts on either side of the bumper cover (green).
  • Loosen the front most nut as well (blue). SPECIAL NOTE- the nut on the passenger side (right) is a LEFT HANDED THREAD.

Headlight Removal

To get to all the fixings of the bumper, the headlights also need to be removed.

  • Start with removing the two corner lights. There is a single 10mm bolt (green) attaching them which can be accessed from the bottom of the car. You will want a long extension to help reach it. Once the bolt is removed, I used a extension again to carefully PUSH the corner light out. I’ve read using a suction cup may work too but I was not successful with this approach. Once its removed, disconnect the three wiring harnesses going into it.
  • With the corner lights removed, you should now be able to remove the bottom bolt on the headlamp (red). It’s hard to see, but you can each your hands into the corner lamp opening, as well as look through the wheel well to see where this bolt is.
  • Next, remove the other two bolts holding the head lamp unit in (blue). On the driver side (left) side you can reach the bolt from inside the engine compartment.
  • Next, I recommend you loosen the bracket held by the two (grey) bolts. This eases removing the headlamp and reinstalling it greatly.
  • I recommend you next use painters/body tape to cover the bumper and headlight surround to avoid any scratches. There will be brackets/units that may come in contact with the body work and scratch easily.
  • Next is time to remove the headlight assembly. To do this gently push while also rotating. It will take some patience to get it out and weird angles/etc. Take your time and proceed carefully.
  • Finally, from the wheel well disconnect the side marker light #16 (brown)

Bumper Shell Removal

With both headlights now removed, there are a few obscured bolts that can be reached to remove the bumper.

  • Start by taping up all joints between the bumper and the fenders to prevent scratches.
  • On both sides, remove the 8mm (orange) nuts. There is a bracket that can then be removed at this point.
  • Remove the blue nut and the clamping bracket. Remember the left handed thread on the left side of right side of the vehicle.
  • If you have headlight washers on your car, there is a quick disconnect in the right side wheel well. Follow the pipe and remove the mounting bracket/disconnect the hose at that junction.

At the point, you should be clear to remove the bumper. Carefully pull it forward and put it in a safe spot. It’s pretty flimsy so be careful of it hitting things/etc.

I also removed the bumper beam itself. It’s held on with 8 nuts (four on either side), as well as four nuts holding the AC drying unit to it. I believe this is optional, but does give a bit more maneuvering room.

Stack Dissassembly

With the bumper out of the way, you should now be able to access the remaining hardware necessary to remove the radiator.

  • Support the condenser unit. I used some 24″ zip ties and a piece of cardboard going through the hood latch hole. This is so that when we remove the radiator, the condenser doesn’t fall downwards.
  • Remove the top two mounting brackets for the radiator that were loosened earlier.
  • Remove the four bolts (green) that hold the top of the shroud on. These are a bit hard to get to, so you will need a long extension coming from the front side, and push the top of the radiator stack backwards to get to the nuts on the rear side.
  • From the front of the car, start with removing the two self tapping screws holding the stack together (red).
  • Although not in the diagram, there are a additional two self tapping screws at the bottom of the condenser unit (blue). Remove these as well.
  • Pull the two long bolts out now that are at the base of the radiator while supporting it.
  • At this point, the radiator should come out the bottom. Carefully maneuver it between the frame rails. I did not need to disconnect the power steering cooler and simply was able to snake past the hoses going into it.
  • Transfer all the hardware (bushing, bolts, angle bracket, clips) from the old radiator to the new one.
  • Perform the reverse of everything above to get the radiator back in. I recommend you hold off on re-installing the bumper and everything along with it until the system is refilled and tested for leaks/etc.

Replacing Thermostat

I recommend while everything is apart here would be a good time to replace the thermostat.

  • Remove the 3 retaining bolts for the thermostat (5mm hex)
  • Remove the thermostat. If its corroded on it may take a little extra persuasion
  • Ensure that the gasket (orange) comes out with it
  • Wipe down the mating surface
  • Place a new gasket onto the new thermostat. Ensure its seats down properly
  • Carefully re-insert the thermostat making sure not to knock the gasket free/cause it to move. Hand tighten the three bolts
  • I torqued each of the hex bolts then to 10nm in a progressive manner to help ensure a good seal

Filling the System

With the components back in, hoses reconnected, O2 sensors reconnected, etc, it’s time to refill the system. I left the bumper and headlights off at this stage incase there were any problems to more easily be able to correct.

  • Mix up, if needed your chosen antifreeze. I did a 50/50 mixtures of Valvoline Zerex G-48 concentrate. I ended up needing about 9.5L but this will depend a bit on how much you initially drained.
  • Open the two 17mm bleeder screws a turn or two at the front of the heads. This allows air to escape during refilling.
  • Place a white paper towel under each of the bleeder screws (I used this as a easy way to see when the blue coolant starts to come out) and to prevent making a mess
  • Slowly start filling the coolant tank with your antifreeze mixture
  • Eventually you should start to see antifreeze seeping out of the bleeder screws. Once you see this tighten them up.
  • The right side will likely see coolant coming out of it first as its slightly lower on the engine
  • Continue filling the reservoir to the max mark
  • This part is optional, but at this stage I did a pressure test on the system just to see if there were any obvious errors
  • Set the heat inside the car to max (although I’m not sure this actually matters as these cars don’t have a valve on the heater core)
  • Start the engine up and watch for leaks
  • Allow the engine to get up to temperature and keep an eye on the coolant level. It will drop slightly as the thermostat opens/etc.
  • At this point, the service manual mentions bleeding the heads again if you had difficulty getting the air out
  • Ensure that the fans kick in (on my car its at around 95C) at which point shut the car off and let it cool down to ambient again
  • Top off the fluid once again to the max point and double check again for leaks/etc.
  • Finally, you will need to get the AC system vacuumed, leak tested and refilled at a garage. Ensure when you reconnect the AC pipe you also replace the o-ring with the appropriate green type. You may consider replacing the dryer at this point as well since the system was opened.

Reassembling the Bumper

The process is pretty much reverse of the disassembly.

  • One thing that I found that made the job much easier was to (i) remove the bracket number 3 and 28 first, and (ii) move the secondary air pump temporarily on the left side of the car. It’s simply held on with two 10mm bolts and gives a lot more access.
  • Again here, patience is the key to getting the headlamps back in. Carefully slide it in and rotate until it fits. You may need to do a bit of repositioning of the rubber gasket as well. Make sure to carefully tape things up to prevent damage/scratches/etc.
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