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Coolant Tank Replacement - Porsche 911 Carrera
 
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Pelican Technical Article:

Coolant Tank Replacement - Porsche 911 Carrera

Time:

2 hours2 hrs

Tab:

$145 to $345

Talent:

****

Tools:

Pliers, 10mm wrench and socket, turkey baster.

Applicable Models:

Porsche 996 Carrera models (1999-05)
Porsche 996 Turbo, GT2, GT3 (2001-05)
Porsche 997 Carrera models (2005-12)
Porsche 997 Turbo, GT2, GT3 (2007-13)

Parts Required:

Expansion tank, coolant

Hot Tip:

Wait overnight so that the coolant is cold

Performance Gain:

No more coolant leaks

Complementary Modification:

Coolant flush

The replacement of the coolant tank is probably one of the top ten jobs that typically need to be done on an older Carrera. The coolant tank is manufactured out of plastic and is prone to breaking. In addition, the plastic tank itself often cracks with age and leaks coolant on to the rear of the bulkhead. Porsche had redesigned this part several times over the past decade, and to this day, there are still problems with the tanks.

When should you replace your tank? If your tank is looking old or yellow, or if you are finding a pool of coolant in the engine compartment, then it's probably time to replace your tank. Lift up the carpet in the rear of your trunk to check. I also recommend replacing the coolant tank when it's really old, particularly if you have your engine out of the car. The hoses inside the engine compartment can be difficult to reach, and having the engine out of the car makes a very difficult job a lot easier.

If you are losing coolant from your engine, and you're not sure where it's going, then you can perform a few relatively simple tests to check. First, get an air pressure adapter that will allow you to hook up a shop compressor to your coolant tank cap. Then, pressurize the system to about 13-15 psi. Let it sit and see if you can hear or see any coolant escaping. If the coolant is getting past the head gasket into the crankcase, it will mix with the oil, and you will be able to see that easily when you empty the oil. If the head gasket is leaking coolant into the cylinders, then they will begin to fill up with coolant, and you can see this when you remove the spark plugs.

When the car warms up, both the heat and pressure of the coolant starts to attack the seam along the edge of the tank, eventually causing it to fail and the car starts leaking coolant. Take a look around the coolant tank. In some instances, you can easily see that it has been leaking. In others, you may only see a faint trace of coolant beginning to emerge from the molding seam. It's important to tackle this problem as soon as possible. Failure to do so could cause a complete loss of coolant and perhaps even engine damage.

The first step is to disconnect the battery. This prevents any possible electrical damage to the system. Please refer to our article on changing the battery for more info.

Now let the car cool down. You might want to wait overnight to make sure that the coolant is not hot. If you open the coolant tank with the car warmed up, it could burn you. There is heat and also pressure in the system. When you are sure that the coolant is not hot, remove the cap and use either a turkey baster or a large syringe to siphon the coolant out of the tank. You'll want to keep siphoning until the level is just at the bottom of the tank. This prevents spinning coolant all over the ground when you remove the tank. Keep in mind that when you remove the tank from the engine compartment, the level will drain back down through the bottom hose. Another option is to completely drain the coolant from the car. Please refer to our article on coolant flushing for more info.

You'll notice that the coolant tank is wedged pretty tightly into the engine compartment. It may seem that there isn't enough room to maneuver it out. You'll first need to remove the emissions air pump at the front of the tank. Begin by removing the hose clamp that secures the hose to the pump with a pair of channel-locks or hose clamp pliers. Then pull the hose off the air pump and set it aside. To remove the air pump, first remove the two 10mm bolts holding the securing bracket to the car at the front of the pump. At the top of the pump, there is a 10mm nut that also secures the front of the coolant tank to the car. Carefully move the pump so that you can unplug the wire connection. Once the connection is unplugged, remove the pump from the car.

Now loosen the hose clamps holding the two upper and one lower hoses going to the tank. You'll find this to be a bit difficult due to the space you have in the engine bay to work with. Now remove the hoses from the coolant tank. You may want to carefully take a small screwdriver and work it between the hose and the tank connection. Coolant hoses sometimes stick to these connections and have to be 'worked' loose. Just carefully work all the way around it and pull it off.

You'll probably get a bit of coolant leaking out of the bottom of the tank. This is normal. Just be sure to clean up any remaining coolant from underneath. It's important to remember that engine coolant tends to attract animals due to its smell and taste. If an animal drinks the coolant, it could make them very sick or worse.

Once all the coolant hoses going to the tank have been removed, you can start to remove the tank from the engine bay. This is the hardest part of the whole job. In our case, our car is a cabriolet which reduces the amount of room you have on top of the engine bay. Carrera 4 models are similar due to the extra components . On regular hardtop models, I'm told that you can simply remove the tank at this point. In our case, you need to lower the motor slightly to remove the tank.

To lower the motor, you'll need to first place a floor jack directly under the oil pan. Our floor jack uses a rubber foot on top of the pad. If your jack does not have a rubber pad, it's a good idea to use a rolled up newspaper in between the car and the jack. Jack the engine up until it just takes the weight of the engine off the car.

Now look at the rear engine support bar. On either end, you'll see an 18mm nut . These nuts secure the engine crossbar to the car. Loosen and remove both nuts. Now carefully lower the jack. The engine will start to lower inside the engine bay. As you lower it, take a look around for any hoses or electrical connections that may be hanging up or being stretched. At a certain point, the bellhousing of the transmission will rest on the rear suspension crossbar, preventing the engine from going any lower.

You now should have just enough room to move the old coolant tank out of the mounting bracket that holds it to the chassis. To remove the tank, pull it towards the engine. Once free, unplug the electrical connection to the coolant level sender at the bottom of the tank. Now pull the old tank out of the car.

Before you install the new tank, you'll probably want to take some time and clean the area around the tank. More than likely, you'll have a buildup of corrosion and baked coolant all over the bulkhead. Clean all of this off before you install the new tank. Some of it may be heavily baked on. You may need to use a stiff brush and a good household cleaner to get it off. (A special word of caution here. You may not to use Simple Green to clean in these instances. Sometimes, the chemical properties of Simple Green can attack aluminum).

Now take the new tank and position it in the engine bay so the "teeth" on the upper surface slide into the bracket in the engine bay. Now push the tank all the way back until it locks in place and the mounting stud at the front of the tank fits through the hole on the front of the tank. Re-install the electrical connection for the coolant level sender, refit the coolant hoses and the air pump.

Now, fill the tank with coolant until it registers in-between the MIN and MAX lines molded into the tank. Start the car and let it warm up. Now recheck the level and add coolant if it has dropped. If you completely drained the cooling system, follow the instructions on how to bleed the cooling system. Pop the cap on the new tank and that's it!

Shown here is a new coolant expansion tank with cap for the Carrera.
Figure 1

Shown here is a new coolant expansion tank with cap for the Carrera. It has been suggested that the newer tanks have been re-worked to prevent the seam from failing; however I couldn't find any noticeable difference between the two tanks.

Use a turkey baster or large syringe to siphon out the coolant inside the old tank.
Figure 2

Use a turkey baster or large syringe to siphon out the coolant inside the old tank. You don't have to get it perfectly dry, but just enough to where the level is at the bottom of the tank. When you lift the tank up and out of the engine compartment, the remaining coolant will drain back down through the lower hose.

Begin by removing the hose going to the emissions pump at the left of the engine compartment (996 only).
Figure 3

Begin by removing the hose going to the emissions pump at the left of the engine compartment (996 only). Use a pair of channel locks to loosen and slide the hose clamp back (purple arrow). Twist the hose back and forth to free it up from off the pump. Then remove the two 10mm bolts at the front edge of the pump (green arrows) and the 10mm nut at the top of the air pump (yellow arrow). This nut also secures the front of the coolant tank to the car. Once free, unplug the electrical connector going to the pump.

Loosen and remove the hose clamps on the lower hose connection to the coolant tank (green arrow).
Figure 4

Loosen and remove the hose clamps on the lower hose connection to the coolant tank (green arrow).

Loosen and remove the hose clamps on the upper hose connections (green arrows).
Figure 5

Loosen and remove the hose clamps on the upper hose connections (green arrows). You may want to carefully take a small screwdriver and work it between the hose and the tank connection. Coolant hoses sometimes stick to these connections and have to be 'worked' loose. Just carefully work all the way around it and pull it off.

On the left side of the engine (997 only) unclip the brake booster pipe on the cross member and lay them off to the side (blue arrows).
Figure 6

On the left side of the engine (997 only) unclip the brake booster pipe on the cross member and lay them off to the side (blue arrows). Remove the plastic lines and the cable plug from the switch over valve between the intake runners (yellow arrow). Loosen the lines for the brake booster (purple arrow). To do this remove the plastic protection, push the holder forward and pull of the line. Put the plastic protector back on right away to keep any dirt or debris out, then disconnect the vent line for the coolant tank (red arrows). Check for slack in your wiring going to the O2 sensors on both sides, and if it looks like it will be tight disconnect the wiring (green arrow).

7:The engine will need to be lowered slightly to allow the coolant tank to be removed from the engine bay.
Figure 7

7:The engine will need to be lowered slightly to allow the coolant tank to be removed from the engine bay. Place a floor jack with a rubber pad or a few rolled up newspapers under the oil pan. This will protect the aluminum from damage.

Figure 8

Remove the 18mm engine mount nut on the right side of the engine (green arrow)

Figure 9

Remove the 18mm engine mount nut on the left side of the engine (green arrow)

With the engine lowered, pull the coolant tank towards the engine (direction of green arrow).
Figure 10

With the engine lowered, pull the coolant tank towards the engine (direction of green arrow). This will disengage the tank from the mounting bracket in the engine compartment.

Don't forget to remove the electrical connection to the coolant level sender at the bottom of the coolant tank.
Figure 11

Don't forget to remove the electrical connection to the coolant level sender at the bottom of the coolant tank. Once free, pull the old coolant tank out of the engine bay.

Once the coolant tank is removed, you will probably see something similar to thisPicture.
Figure 12

Once the coolant tank is removed, you will probably see something similar to thisPicture. Left behind is a mess of baked coolant on the bulkhead behind the coolant tank. It's a good idea to spend some time and clean everything up before continuing.

Fit the coolant level sender to the new tank and reconnect the electrical connection.
Figure 13

Fit the coolant level sender to the new tank and reconnect the electrical connection. Position the new tank in the engine bay. It can be a little tricky to get the "teeth" of the new tank (green arrow) to line up in the bracket (yellow arrow) on the car. Once the tank is positioned, push it back as far back as it will go, making sure that the front edge of the tank fits over the mounting stud. At this point, re-fit the coolant hoses to the new tank. If any of the hoses look suspect, replace them before continuing. Also be sure to reconnect the electrical connection to the air pump. Re-install the two 10mm bolts and the 10mm nut that also secures the coolant tank to the bulkhead.

The last step is to re-fill the coolant tank in between the MIN and MAX marks.
Figure 14

The last step is to re-fill the coolant tank in between the MIN and MAX marks. If you have completely drained the system, you'll also need to follow the factory procedure for bleeding air from the system.

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Comments and Suggestions:
rickrpm Comments: To avoid headaches suggest ordering the level sensor with new tank. Mine was brittle from all those years in the heat of the engine bay and broke when I tried to disconnect the plug. Other than that it was an easy job on a 996C4 , engine lowering per article is a must. Great article!
June 27, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
idahorocks Comments: I just completed this repair on my 2007 Carrera S Coupe and wanted to share some tips from my experience. It took me about 4 hours to complete. Review the air box removal steps on this site. That will need to come out to get easier access to the reservoir and remove it. I found channel locks and small vice grips were useful in getting the Porsche hose clamps off. I had to lower the engine to get room to remove the reservoir. It's actually not that difficult and I think it could be done earlier to get better access to the hoses for removal. The reservoir was still a little challenging to slide far enough to the right that it slips out from its teeth allowing it to be removed. Remember how you manipulated it to come out because it will likely go back in with less difficulty if you reverse that procedure. It seems to take just the right amount of twisting a pulling.

In the end, it was not as hard as I thought. I even had my 8 year old helping on some of the steps. Thanks, Pelican Parts, for the how-to and the parts!
June 12, 2016
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 

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