Where to get part numbers ?

[mikkhh]

Not red engine related, but I bought AFTERmarket exhaust back pressure for my Merc 2.2diesel five years ago, the sensor was reading complete garbage and fluctuating like crazy. OEM sensor costed twice as much, but in the end I still bought OEM.

If you want cheap and good you MUST buy cheap part and also good part.

Big rig parts cost difference is even bigger and so is the temptation. Paccar MX13 aftermarket boost sensor was like 20dollars and OEM was 300. The choice to go is OEM, aftermarket price might be tempting but it is not worth the downtime. I ordered one IMAP sensor from official dealer and second from so called reputable parts store. The one from $tealer is latest revision and part code, but the part that is bit cheaper from parts retailer is older revision new old stock. It is common for aftermarket parts retailers to sell new old stock old part code OEM parts around my area. Probably main dealers are not allowed to sell those parts and so they are sold at a discount to big wholesalers.

There was early 2000s GM car that needed turbo boost pressure solenoid changed. OEM was 300, aftermarket was 30. Well since the car was old I was like okay, let's choose the cheaper option. Turbo underboost codes got replaced with overboost. I checked all the vacuum lines again to make sure I did not mess something up and bought next aftermarket solenoid. Still same story, I was questioning myself after that, but symptoms did change a little bit. Well the third or fourth aftermarket solenoid worked. Those are not merely on off solenoids, but they use PWM signal to control the VNT turbo actuator. Lots of time wasted on troubleshooting and also downtime. On a big rig downtime means lost money and there is no wise reason to pick up a penny and lose a dollar when it comes to cheap parts and long term cost.