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Engine overheats, no heat and P00B7, P2181

Diagnose and fix Engine overheats, no heat P00B7, P2181 GM vehicles

Fix an engine overheats, no heat P00B7, P2181 problem on GM vehicles

GM has issued a service bulletin # PIP5300 for the vehicles listed below. The symptoms covered in the bulletin are Engine overheats, no heat and P00B7, P2181. If you own one of the vehicles listed below, this bulletin may pertain to you. GM reports that some of these vehicles may experience engine overheating, poor heater performance, and an “AC OFF” warning light. In addition, a code scan may reveal trouble codes P00B7 or P2181.

P00B7 Engine coolant flow insufficient
P2181Engine cooling system performance

Vehicles affected by service bulletin #PIP5300

2014 – 2015 Buick Regal
2013 – 2015 Cadillac ATS
2014 – 2015 Cadillac CTS
2013 – 2015 Chevrolet Malibu

2014 – 2015 Chevrolet Impala equipped with 2.0L or 2.5L engine (RPO’s LCV, LKW and LTG)

Cause of overheating, poor heater performance, AC OFF light and P00B7 or P2181

GM has determined that the plastic water outlet assembly,

Water outlet restriction

Water outlet restriction

which is attached to the rear of the cylinder head may have plastic “flashing” still attached from the manufacturing process or may have debris stuck inside. The water outlet assembly has hoses attached that run to the heater core and surge tank.

GM recommends removing the water outlet assembly and checking for flashing or debris and replacing the assembly if the flashing is found. Then clean any debris from the hoses. If no flashing is found, check the upper heater core hose and coolant bypass pipe at the water outlet for a black plug. If you find the plug, remove and discard it.

1) Drain the coolant from the engine
2) Remove the water outlet assembly from the engine
3) Check for flashing restriction in the hose outlet portion (see photo below)
4) Replace water outlet housing and clean debris from hoses.

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Posted on by Rick Muscoplat

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