Need to know year, make, model, and engine to provide any answers to your question.
The exhaust manifold for an E250 is usually sold as a complete kit. The nut is a standard issue, and is between the a half inch and a full inch diameter.
under the dash
2002 e250 van driver side window installation
Eventually you will have to replace it. They cost around $150.00 for the part. But, you can drive the truck for a long time without any real problem developing. A friend of mine has been driving his for almost two years that way.
Driver side, under dash.
Look under the vehicle and count them.
T 45. The slots on those pins is very shallow, so be carefull. My 2000 Ford E250 required a T 47
On a 2004 E250, the bulb is loacted behind a panel on the passenger side rear door. The steel panel is secured to the door via four screws.
most e250 turn sig. flasher are located on fuse box (under dash) small metal box
I have a '95 E150 and a '96 E250, both are 4.9 straight 6 cyl. One has 1 O2 sensor and the other has 2, one on each half of the exhayst manifold. I believe the 96 has 2. but it is an E250, not sure about the '96 E150.
under the passenger door bolted to the frame rail
drivers side by door under van attached to inside of frame