SureTrack Real Fix: Lean Whistle

Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.


Lean conditions on a vehicle can be caused by many factors. What would a whistling noise under the hood have to do with this? Follow this Real Fix to see how this Volvo C70 with a P2187 lean code was diagnosed and repaired.

Vehicle
2012 Volvo C70 T-5 2.5L

Title
P2187, Replaced Positive Crankcase Ventilation Oil Separator

Complaint
The customer states the check engine light is on.

Cause
Connected a scan tool and found code P2187 – System Too Lean at Idle (Bank 1). With the scan tool connected to monitor live data, performed a road test and found the long term and short term fuel trim was out of specifications. With the engine at normal operating temperature and at idle noticed a whistling sound coming from the engine. Performed a visual inspection of the air intake system and found no apparent faults. Removed the engine oil dipstick with the engine running and found the whistling noise changed pitch. Used an electronic stethoscope on the engine oil filter housing and found with the engine running the noise was coming from the engine oil filter housing. Removed the engine oil dipstick with the engine running and installed a vacuum gauge into the oil dipstick tube and found the specified 2.5 inches of vacuum was well above specifications. The positive crankcase ventilation valve is integrated into the positive crankcase ventilation oil separator (oil trap box/oil filter housing) and is replaced as an entire unit. The failure of the positive crankcase ventilation oil separator is common on this style engine. The results of these tests verified the positive crankcase ventilation oil separator was faulty.

Correction
Replaced the positive crankcase ventilation oil separator, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.


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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.