This is caused by improper PCM control software not allowing the active shutter to open properly, resulting in lower cooling performance at idle. Simply reprogram the PCM with the latest available software.
Mazda
Owners of 2019-2020 Mazda3 and 2020 CX-30 vehicles may complain about the A/C blowing warm air after restarting a warm engine.
This is caused by improper PCM control software not allowing the active shutter to open properly, resulting in lower cooling performance at idle. Simply reprogram the PCM with the latest available software.
Then clear the DTCs, turn the vehicle off and exit the vehicle. Close and lock all doors and wait at least 10 minutes. Restart the engine and verify the repair.
Photo courtesy of Mitchell 1
Example of oil line T-piece.
Mercedez-Benz
Owners of a 2022 Mercedes-Benz Sprinter 2500 equipped with an automatic transmission may note that after a cold start and/or under full-load conditions, there is a delayed or non-existent upshift, in combination with severe vibrations. The engine may switch to limp-home mode and there may be an interruption of tractive power, jolts, etc. The MIL will be on accompanied by various fault codes logged in the fault memory (boost pressure, injection, fuel rail pressure, etc.).
The cause may be a transmission oil line leak/damage. This may be due to a previous repair using the wrong T-piece. An incorrect or incorrectly matched T-piece (restrictor) can result in the afore-mentioned symptoms. Make a visual inspection of the oil line and restrictor. If there is a fault in the line or restrictor, replace the oil line. The connections of the leaking oil line must never be separated or replaced with other components. Always replace the entire oil line. Use “leak oil line” P/N A6420708132.
Engine coolant water mix
Just a reminder. When filling/topping off engine coolant, when using coolant that requires a 50/50 water mix, always avoid using tap water or well water. Always use only distilled water in the mix. If tap or well water is used, hard water particulates/minerals can build up between the water pump seal faces can lead to premature water pump failure, resulting in a leak.
Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety ofspecialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.
