I have 2003 crossover over heating - FX35 Infiniti Cars & Trucks

In the image below, do you see the thermostat housing? It's where the upper radiator hose attaches to the engine--above the water pump pulley. I think the crossover pipe is behind the housing and runs down the middle of the engine. Ok?

Thermostat? engine cooling?
2 engines, here, LYA adn LY7.
nobody here posts engine, why do that?
so ill post only for 1.
the LA1
here are the steps.
NO FSM Sux huh? nor an alldata.com account, why not that? 15 bucks?


STAT out.
Remove the air cleaner and duct assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls - 3.4L.

Drain the coolant until the coolant level is below the thermostat. Refer to Cooling System Draining and Filling (Refer To List 1) .

Remove the crossover exhaust pipe. Refer to Exhaust Crossover Pipe Replacement (Refer To List 2) in Engine Exhaust.

Remove the radiator hose from the thermostat housing.

Remove the thermostat housing bolts and clean any sealer from the bolt threads.

Remove the thermostat housing and gasket.
remove STAT
next is crossover page.

Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection (Refer To List 1) in Engine Electrical.

Remove the throttle body air inlet duct.

Drain the coolant from the cooling system. Refer to Cooling System Draining and Filling (Refer To List 2) in Engine Cooling.

Remove the inlet radiator hose from the engine. Refer to Radiator Inlet Hose Replacement (Refer To List 3) in Engine Cooling.

Remove the thermostat bypass pipe. Refer to Thermostat Bypass Pipes Replacement in Engine Cooling.



Remove the exhaust crossover heat shield bolts.

Remove the exhaust crossover heat shield.

1. Remove the exhaust crossover pipe studs/nuts.
2. Remove the exhaust crossover pipe.

end , remove.

now the bypass pipe FWD cars SUCK

1. Disconnect the left engine mount strut from the engine.
2. Remove the heater hose from the bypass pipe.
3. Remove the thermostat bypass pipe to throttle body nut.
4. Use the J 38185 in order to remove the thermostat bypass pipe hose clamps (1,5).
5. Remove the thermostat bypass pipe to cylinder head nut (3).
6. Remove the thermostat bypass pipe bolt (4).
7. Remove the thermostat bypass pipe hose.
8. Remove the thermostat bypass pipe.

sigh.....
why not log in to alldata.com
read the page then ask ques tons that are not clear.
and next time post the engine type.
above is just 1 engine.

I have done this and the procedure calls for removing the exhaust crossover which you don't really have to do however it is a tight fit and probably will make life easier to get a wobble extension since some of these bolts you cant get right over. It is located on the driver side under the exhaust crossover and a few small waterlines must be removed in order to access it. If I remember correctly the bottom bolt on the housing does not have to be taken out all the way to get it off. the hard part is getting to bolts loose, Just take your time and realize its a hard place to work in.

You will need to remove your air cleaner and duct assembly. You will then see the thermostat housing sandwiched between the back of the intake manifold and the exhaust crossover pipe. The service manual says to remove the exhaust crossover pipe, but trust me, you do not want to attempt this unless you have access to a torch to heat the nuts that hold the thing to the exhaust manifolds. If you break a stud, then you are going to be removing an exhaust manifold for broken stud removal. If you take the 8mm screws out of the heat shield on the exhaust crossover pipe, you can wiggle the heat shield out. This will provide enough room to get the lower thermostat housing bolt out. It is a pain to do it this way, but it works and will prevent broken exhaust pipe studs. Sometimes the little 8mm bolts will also break, but since they only hold the heat shield, it is of no great consequence.

Then all you have to do is remove the two bolts that hold the thermostat housing to the manifold. The thermostat is directly under it.
Then the only other real "trick" is getting the thermostat and O-ring to stay in the correct position while you put the thermostat bolts back in. A trick that I use is a small wooden wedge. I put the thermostat housing into place over the thermostat and O-ring, then place mt wedge between the thermostat housing and the crossover pipe to hold the thermostat housing in place while I start the bolts. Otherwise, the thermostat tends to slide out the bottom while you are trying to get the bolts started.

Let me know how it goes...

Hello vocalviixen,

The pipe that you referred to is the exhaust crossover pipe. Below I've included removal and installation instructions.

Also, the procedure for bleeding the coolant system is critical; if you need those instructions please post the question.

REMOVAL PROCEDURE
1. Disconnect the battery ground (negative) cable.
2. Remove the throttle body air inlet duct.
3. Drain the coolant from the cooling system.
4. Remove the inlet radiator hose from the engine.
5. Remove the thermostat bypass pipe.
6. Remove the exhaust crossover heat shield bolts.
7. Remove the exhaust crossover heat shield.
8. Remove the exhaust crossover pipe studs/nuts.
9. Remove the exhaust crossover pipe.
INSTALLATION PROCEDURE
1. Install the exhaust crossover pipe.
2. Install the exhaust crossover pipe studs/nuts.
3. Tighten the exhaust crossover pipe studs/nuts to 18 lb ft.
4. Install the exhaust crossover heat shield.
5. Install the exhaust crossover heat shield bolts.
6. Tighten the exhaust crossover heat shield bolts to 89 lb in.
7. Install the thermostat bypass pipe.
8. Install the inlet radiator hose to the engine.
9. Fill the cooling system with engine coolant.
10. Install the throttle body air inlet duct.
11. Connect the battery ground (negative) cable.


Regards,
netvan

Thermostat
Removal & Installation
To Remove:

1. Before servicing the vehicle refer to the precautions at the beginning of
   this section.
   
   
2. Partially drain the coolant, (until the level is below the thermostat).
   
3. Remove or disconnect the following:
   
   
   
   • The air cleaner and duct assembly
     
   • The crossover exhaust pipe
     
   • The radiator hose from the thermostat housing
     
   • The thermostat housing bolts
     
   • Any remaining sealer from the bolt threads
     
     
     
     
     
     
     
     
     
     
     
   • The thermostat housing
     
   • The gasket
     
   • The thermostat

To Install:

1. Install or connect the following:
   
   
   
   • The thermostat
     
   • The thermostat housing
     
   • The gasket
     NOTE: Apply RTV sealer, GM P/N 1052366 or the equivalent, to the
     thermostat housing bolt threads.
     
     
   • The thermostat housing bolts
     
     
     
     1. Torque to: 18 ft. lbs. (25 Nm)
     
     
   • The radiator hose to the thermostat housing
     
   • The crossover exhaust pipe
     
   • The air cleaner and duct assembly
     
   • The coolant
   
   
2. Thoroughly inspect the cooling system for leaks.

No you cannot. You have to buy the whole intake.

Exhaust Crossover Pipe Replacement
Removal Procedure

1. Disconnect the battery ground (negative) cable.
2. Remove the throttle body air inlet duct.
3. Drain the coolant from the cooling system.
4. Remove the inlet radiator hose from the engine.
5. Remove the thermostat bypass pipe.
6. Remove the exhaust crossover heat shield bolts.
7. Remove the exhaust crossover heat shield.

1. Remove the exhaust crossover pipe studs/nuts.
2. Remove the exhaust crossover pipe.

1. Remove the air cleaner and duct assembly.
2. Drain the coolant until the coolant level is below the thermostat.
3. Remove the crossover exhaust pipe.
4. Remove the radiator hose from the thermostat housing.
5. Remove the thermostat housing bolts and clean any sealer from the bolt threads.
6. Remove the thermostat housing and gasket.

Removal Procedure

According to the factory service manual you must unfortunately remove the crossover heat shield as well as the crossover exhaust pipe to access the thermostat housing. What a stupid design. If you think this is hard though wait until you need an alternator...

Had this problem once mine was 13mm bolt. I took an old wrench heated it with a torch and bent it just the right angle. worked perfect.