2013 Audi S5 Engine Replacement in Ann Arbor, MI

2013 Audi S5 with head gasket failure

2013 Audi S5 experienced a sudden engine coolant loss problem. The engine had been partially disassembled by the Audi dealership with the supercharger and lower intake manifold removed. The Audi dealer recommended the complete replacement of the engine. The customer and their vehicle extended warranty company wanted a second opinion on the extent of the damage and repair cost, and the vehicle was towed to our shop.

Audi S5 Head Gasket Failure Symptoms

Cylinder head gaskets seal the combustion chamber, coolant passages, and oil passages. A failed head gasket can allow coolant to enter the combustion cylinders or enter the crankcase and contaminate the engine oil. 

What are the first signs of a failed head gasket?

Coolant in the cylinders can cause the following:

  • White smoke coming from the tailpipe
  • Bubbling in the radiator and coolant reservoir
  • Unexplained coolant loss with no visible leaks
  • Engine overheating

Coolant in the crankcase can cause the following:

  • Cream-colored engine oil
  • Thickened engine oil
  • Increased oil level on the dipstick

Diagnosis

The owner reported they had been driving on the highway for 2 hours when white smoke suddenly started coming from the exhaust, and the check engine light came on and stayed on. The driver pulled the vehicle over to the side of the highway. With the engine idling, the low coolant level warning light came on, so the driver switched the engine off. The vehicle was towed to the local Audi dealership, where it was inspected, and an engine replacement was recommended.

The Audi dealership technician reported the white exhaust smoke smelt like burnt coolant. When they pressure-tested the cooling system, the remaining coolant quickly emptied into the oil pan. The supercharger was removed, and the coolant-heated PCV valve was checked for failure and found to have no coolant leaks. Next, the spark plugs were removed, and no visible sign of coolant was found in the cylinders. The technician suspected a failed head gasket.

Our Audi technician could not confirm the previous cooling system test due to the engine being partially disassembled. From experience, our technician agreed with the dealership's conclusion of a head-gasket failure. Our technician also visibly confirmed coolant in the engine oil.

After further inspection, the technician noted that besides coolant being mixed with the engine oil, the oil was extremely dirty and thick. The oil filter was removed and found to be completely plugged with thick, black sludge. It was crushed in on itself from the oil pump trying to push the sludge-thickened oil through the plugged filter. The oiling system had been completely bypassing the oil filter and sending unfiltered oil throughout the engine for a long time before the head-gasket failure!

The technician commented that in 33 years of working on Volkswagen and Audi vehicles, he had never seen a car that had been so poorly maintained. From these observations, the technician suspected the engine head-gasket had failed due to not performing regular cooling system service. The head gasket was corroded by acid buildup in the coolant and eventually broke through into an oil drain back passage into the crankcase.

2013 Audi S5 plugged engine oil filter
2013 Audi S5 plugged oil filter compared to a new oil filter
2013 Audi S5 engine oil sludge caused by not changing the engine oil and a head gasket leak
2013 Audi S5 engine sludge caused by head gasket leak and poor oil and filter change maintenance. Notice the creamy coating of coolant-contaminated oil covering dark sludge deposits caused by infrequent oil and filter changes.

Recommendations

This Audi only had 118k miles, but considering the poor service history, the very poor condition of the engine oil and oil filter, and the internal coolant leak, the technician did not recommend any repairs to this engine. Due to the cost of a new engine, the owner chose to install a good, low-mileage used engine. The vehicle had an extended warranty, and the insurance company agreed to cover some of the repair costs.

What Causes Head Gasket Problems?

Age: The older a vehicle gets, the more wear and tear the head gaskets suffer. Each time a vehicle goes through a cold start and warm-up cycle to operating temperature and then cools down when turned off, the head gasket is subjected to great expansion and contraction stress. Head gaskets on turbo-charged and supercharged engines must withstand even greater cylinder pressure and heat stress. Eventually, the head gasket seal is broken, and they leak.

Heat: The most common cause of head-gasket failure is engine overheating. Excessive heat can distort or warp the engine block or cylinder head, causing an uneven clamping force on the gasket and allowing the cylinder pressure to cause a head-gasket failure. Always turn the engine off as soon as safely possible if the check engine light or engine heat warning light comes on. Have the vehicle towed to a repair shop to have the overheating problem investigated.

Poor Maintenance: Regular cooling system maintenance will prevent corrosion and failure of the head gasket. Anti-corrosion additives in engine coolant (antifreeze) deteriorate with age. This additive breakdown allows acids to build up in the coolant and attack the interior of the engine coolant passages, water pump, thermostat, coolant pipes and hoses, and gaskets.

Poor Design: Unfortunately, some vehicle designs are prone to developing premature head-gasket problems. Manufacturer's extended cooling system service periods can also cause problems. The vehicle service industry standard recommendation of a cooling system flush and coolant replacement every two years is good value if you plan to keep the vehicle.

Audi S5 Engine Replacement Repair

Following Audi service and repair procedures, all under-car shielding, exhaust system, front clip assembly, sensors, wiring, and hoses were disconnected inside the engine bay. The complete power-train assembly, including the engine, transmission, and drive axles, was disconnected and lowered from the vehicle.

2013 Audi S5 engine removal

Next, the engine was separated from the transmission, and all external accessories were removed from the old engine and prepared for reuse on the used engine.

2013 Audi S5 engine separation from transmission

The used replacement engine included an assembled cylinder block fitted with pistons, rings, connecting rods, crankshaft, bearings, cylinder heads, camshafts, timing chain, and sprockets. Preparation included checking, cleaning, and transfering fuel and electrical assemblies, engine mounts, intake and exhaust manifolds, valve covers, oil pan, oil pump, timing covers, water pump, transmission drive plate, and accessory drive belt.

2013 Audi S5 used engine assembly
2013 Audi S5 3.0L used engine assembly

New spark plugs, valve cover gaskets, accessory belt, coolant pipes, intake pipe boot, water pump, crankcase vent valve (PCV), and deteriorated vacuum hoses were all replaced. The engine and transmission assembly were reassembled, the power train was bolted into the chassis, the body panels refitted, and the engine was test run in the shop.

2013 Audi S5 3.0L v6 stuck intake manifold flap error code
2013 Audi S5 3.0L v6 stuck intake manifold flap error code

The check engine light came on with fault codes for both intake manifold runner flaps. This was a problem before the head gasket failure (more evidence of poor maintenance). The vacuum supply and vacuum operation of the flaps were checked, and the flaps worked when manually activated. The intake runner flap solenoid was replaced, and the flaps were verified to work correctly. The error codes were cleared and did not return, indicating the engine was operating correctly.

The vehicle was given a thorough test drive and a final inspection to verify the replacement engine was functioning correctly.

The vehicle had many other problems due to the long-time lack of maintenance, but they were unrelated to the engine repair. The owner declined our other recommended services and repairs.

Cost

The Audi dealer quoted the owner $25,000 for just the new engine assembly. The vehicle owner felt the final cost estimate for the installed new engine far exceeded the value of this ten-year-old vehicle. The used engine cost just under $10,000, which saved this customer a significant amount of money. The used replacement engine had lower mileage than the failed engine, so the owner felt this repair was good value.

These prices did not include additional parts, fluids, or labor that were required to complete the engine replacement.

Tips

  • This was a classic case of a vehicle being driven until it quit running. Regular maintenance and vehicle inspections would have prevented this very expensive engine repair. A coolant flush and replacement every two years and regular oil and filter changes would have amounted to less than 10% of what this engine replacement cost.
  • The Audi S5 supercharged engine uses a coolant-heated PCV valve, which can fail and leak coolant into the crankcase and engine oil. This PCV coolant leak is a more common problem and is often mistaken for a head gasket failure. The PCV coolant leak starts slowly and increases over an extended period of time. If the vehicle's coolant level steadily drops, with no external coolant leak, the PCV valve should be the first thing that is checked. When the leak becomes significant enough, the coolant will cause the engine oil to become cream-colored when it mixes with the hot engine oil. If left long enough, the contaminated oil will thicken to the consistency of a milkshake, losing its lubrication quality and quickly destroying the engine bearings!
    To check the PCV valve, the supercharger must be removed to gain access to the valve. Coolant within the crankcase vent hose will be obvious if the PCV valve leaks. The leaked coolant is also sucked into the intake manifold and burnt by the engine. The resulting unmistakable sweet, burnt coolant smell and white smoke and steam from the exhaust can cause technicians who are not experienced with the Audi S5 to conclude a head gasket is leaking. This is a very easy mistake for a technician to make and a very expensive mistake for the vehicle owner to pay for! Choose your Audi mechanic carefully!
  • This case can also be used as a cautionary example when buying a used Audi with an unknown service history! The external and interior condition of this vehicle was very clean, and anyone would have been tempted to buy it. But first impressions can be very deceiving. The hidden damage of poor maintenance can be very expensive!
    If you are buying a used vehicle, we strongly recommend getting a service history report and a before-purchase vehicle inspection from a repair shop with extensive experience with Audi vehicles. It can save you a lot of money and grief!
2013 Audi S5 engine inspection
2013 Audi S5 engine replacement final inspection

 

Recommended Audi Repair Shop in Ann Arbor, MI

Contact Stadium Auto Service for all Audi service and repair in the Ann Arbor, Michigan area. Our Audi technicians have the skill and experience to diagnose and repair your Audi S5 problems correctly. We are Audi service specialists.

Stadium Auto Service

Ann Arbor, MI 48103
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