1991 Nissan Pathfinder Manifold Stud Fix

1991 NISSAN PATHFINDER
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RYAGUDELO
  • MEMBER
  • 5 POSTS
I have a 1991 Nissan Pathfinder 4Dr V6 3.0L SUV and has a 170,000 miles with a left exhaust manifold problem brought to MIDAS to repair it, but during the replacement of the left exhaust manifold one of the studs broke(but was not told), and later found. I returned to MIDAS, and was told that to fix it, the broken stud portion needs reboring which is beyond their competence because their shop is not equip with the necessary tool, and require to dismantle the exhaust from the engine. What should be done? What is the work hour estimate and how much? Is it worth repairing it though it still run at 13 miles per gal.?
Jan 3, 2007 at 6:47 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
If the exhaust manifold is not sealed properly and it decides to leak, the O2 sensor will tell the computer that the engine is running lean therefore the computer will compensate by dumping fuel and there goes your fuel mileage

Midas is a big business-they should contract the job to a machinist. Your money was good on your part-but the service is not. I go for the quality not quantity.
Jan 3, 2007 at 9:08 PM

Suggested Repair

Have a machine shop extract or rebore the broken left exhaust manifold stud so the manifold can seal. Midas should subcontract that work rather than leave the repair incomplete. An exhaust leak can make the oxygen sensor read lean, causing the computer to add fuel and reduce mileage.

Conversation Summary

The owner of a 1991 Nissan Pathfinder had the left exhaust manifold replaced at Midas, where a stud broke and was not disclosed. The shop later said extracting or reboring the stud required tools and exhaust disassembly beyond its capability. The expert said an unsealed manifold can cause the oxygen sensor to report a lean condition, prompting extra fuel and worse mileage, and advised contracting a machinist to finish the repair properly.

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