Changing Temp sensor upstream from turbocharger
- Thread starter rjjb
- Start date
98Firebird
Well-known member
You'll need the following:
3/8 flex head ratchet
e10 socket
e12 socket
3" extension
6" extension
flat head screwdriver
17mm wrench
turbo flange gasket
doughnut gasket for the exhaust elbow
First take the ratchet and e10 and undo the 3 bolts on the top side of the turbo heat shield, this leaves 1 bolt that you will need the 6" extension for, it is located down and on the drivers side of the heat shield, if you feel back there along the leg of the heat shield that runs down to that bolt you'll see/feel what I'm talking about it's an e10 also. After removing the final bolt (should have 4 total unless someone was previously in there and left the bottom heat shield bolt out) lift the heat shield out of place and sit it to the side. Now you will need to remove the e12 bolt on the exhaust elbow clamp (very easy to see once the heat shield is off, here you will use the ratchet and e12 no extension to loosen the clamp bolt and take it all the way out and then will need to pry the clamp apart a little to break it free of the exhaust, the doughnut gasket on this elbow should be replaced so you don't have to worry about any leaks (it's on the bottom side of the elbow facing towards the particulate filter). Now put the 3" extension on your ratchet as well as the e12 again and there will be 3 e12 bolts holding the elbow onto the turbo, you will have to feel for the bottom one, be careful as there are 2 bolts very close to each other when feeling for the bottom bolt, it will be the one sunk in a little closer to the turbo and just slightly higher up than the other bolt. The bottom bolt you only need to loosen a few turns you do not have to completely remove it at this time. After loosening the bottom bolt remove the top 2 bolts completely and the elbow should come free. After this is out you can look down right in the area where the elbow was on the turbo and that will be the sensor you are after. You will need to take the 17mm wrench and loosen the sensor making sure to pay attention to the angle it is installed at. If the sensor is somewhat seized and it feels like it is going to round off STOP because at this point if you round off the sensor it will probably mean turbo removal to get at the rounded sensor! Apply some penetrating oil and take a break for a while and try it again, if it still does not want to break free you can take apart the connector on the temperature sensor with a pick in order to get the 17mm box end on for a better grip, alternatively you could snip the plug in off but I'm not a huge fan of that. Once the sensor is out as you try to remove it you will see it's connected to the main harness there at the passenger fuel rail, you can pull the connector away from the rail and it will unclip giving you some more room. Once you can get at the connector you'll need to pop the grey safety latch on the connector back (it'll move maybe 1/16 or so when you get it) after that just pinch the tab you just released and pull and the sensor should be totally free. Now installation will basically be the reversal of removal just make sure to replace the doughnut gasket and the flange gasket that goes between the turbo and the elbow (will be held in place by the 1 screw left in the turbo) make sure after you remove the bottom bolt completely to change the gasket you reinstall it after putting on the new gasket (gasket has clips and will hold itself to the turbo). About the only other tip I have is to get all the bolts and clamp installed loosely before tightening anything down (just like with any part that has multiple bolts). It's not the easiest thing in the world the first time you do it, but after that it's one of those things where you'll say "hey if I ever have to do that again it'll only take 5 minutes" hope that helps, let me know if you have any issues.
3/8 flex head ratchet
e10 socket
e12 socket
3" extension
6" extension
flat head screwdriver
17mm wrench
turbo flange gasket
doughnut gasket for the exhaust elbow
First take the ratchet and e10 and undo the 3 bolts on the top side of the turbo heat shield, this leaves 1 bolt that you will need the 6" extension for, it is located down and on the drivers side of the heat shield, if you feel back there along the leg of the heat shield that runs down to that bolt you'll see/feel what I'm talking about it's an e10 also. After removing the final bolt (should have 4 total unless someone was previously in there and left the bottom heat shield bolt out) lift the heat shield out of place and sit it to the side. Now you will need to remove the e12 bolt on the exhaust elbow clamp (very easy to see once the heat shield is off, here you will use the ratchet and e12 no extension to loosen the clamp bolt and take it all the way out and then will need to pry the clamp apart a little to break it free of the exhaust, the doughnut gasket on this elbow should be replaced so you don't have to worry about any leaks (it's on the bottom side of the elbow facing towards the particulate filter). Now put the 3" extension on your ratchet as well as the e12 again and there will be 3 e12 bolts holding the elbow onto the turbo, you will have to feel for the bottom one, be careful as there are 2 bolts very close to each other when feeling for the bottom bolt, it will be the one sunk in a little closer to the turbo and just slightly higher up than the other bolt. The bottom bolt you only need to loosen a few turns you do not have to completely remove it at this time. After loosening the bottom bolt remove the top 2 bolts completely and the elbow should come free. After this is out you can look down right in the area where the elbow was on the turbo and that will be the sensor you are after. You will need to take the 17mm wrench and loosen the sensor making sure to pay attention to the angle it is installed at. If the sensor is somewhat seized and it feels like it is going to round off STOP because at this point if you round off the sensor it will probably mean turbo removal to get at the rounded sensor! Apply some penetrating oil and take a break for a while and try it again, if it still does not want to break free you can take apart the connector on the temperature sensor with a pick in order to get the 17mm box end on for a better grip, alternatively you could snip the plug in off but I'm not a huge fan of that. Once the sensor is out as you try to remove it you will see it's connected to the main harness there at the passenger fuel rail, you can pull the connector away from the rail and it will unclip giving you some more room. Once you can get at the connector you'll need to pop the grey safety latch on the connector back (it'll move maybe 1/16 or so when you get it) after that just pinch the tab you just released and pull and the sensor should be totally free. Now installation will basically be the reversal of removal just make sure to replace the doughnut gasket and the flange gasket that goes between the turbo and the elbow (will be held in place by the 1 screw left in the turbo) make sure after you remove the bottom bolt completely to change the gasket you reinstall it after putting on the new gasket (gasket has clips and will hold itself to the turbo). About the only other tip I have is to get all the bolts and clamp installed loosely before tightening anything down (just like with any part that has multiple bolts). It's not the easiest thing in the world the first time you do it, but after that it's one of those things where you'll say "hey if I ever have to do that again it'll only take 5 minutes" hope that helps, let me know if you have any issues.
Do you know the part # for doughnut gasket. Your procedure looks great, I only have 5600 miles on the vehicle which is a Class C RV. As this part appears to be part of the emissions I'm as going to contact MB to see if they will cover it. It is past 5 years but the is a note in the warranty manual regarding California emissions where it is covered for 7 years or 70,000 miles.
jasonbarretto
Member
+1 part # for doughnut gasket?
Also what is the part number of the EGT sensor?
Also what is the part number of the EGT sensor?