Evaporator Core Leakage

Recent inspection: The dash board, and evaporator housing and core were removed. The field agent confirms there is dye in the A/C system that was added prior to the time of inspection. The evaporator has oily dye on it near the lower right side seam, with dust and dirt accumulation exhibited. There is also moderate term leakage stains in the evaporator case. There was no corrosion, or impact seen. The repair facility did not demonstrate any other AC system related problems. The failure is consistent with a material failure of the evaporator core. 

The evaporators role in a A/C system 

The evaporator actually removes heat from the inside of the car when you have the A/C on.  The evaporator core is part of the air conditioning system that is located on the low side. Evaporators are usually made of aluminum. They look like, and in fact are similar to radiators, only thicker and smaller in overall size. Like radiators, evaporators consist of a series of internal tubes or “flow paths” with fins attached to them. Air can pass freely through the fins, just like a radiator. But unlike a radiator, where the internal tubes carry moving engine coolant, the passages in the evaporator carry moving refrigerant.

VANOS for timing was used beginning in 1994 with a single VANOS. 

The VANOS has the ability to adjust the valve timing which improves the engine power dynamics and reduces the tailpipe emissions. It optimizes the camshaft angle for all ranges of the engine operation, as both intake camshafts, and exhaust camshafts are continuously adjusted to the optimum.

Here are just some of the benefits of the VANOS.

  • It increases torque at lower to mid range engine speeds with no loss of power in the upper range engine speeds.
  • It allows for increased fuel economy due to optimized valve timing angles, and reduced emissions.
  • You enjoy a smoother idle quality due to optimized valve overlap. (Who could have guessed)!
The engine control module activates the VANOS solenoid valve based on the particular DME program mapping. Then hydraulics kick in and directs the flow of the engine oil. The controlled oil flow acts on the mechanical component of the VANOS to position the camshafts.

You may wonder why we showed the internal parts of a VANOS; note the small seals or o-rings in that photo. When one or more of those become fatigued with age, they begin leaking oil. So, if someone tells you that you have a leak in the VANOS, and you cannot begin to understand what that is all about, (because it looks like just one big heavy hunk of steel), now you know! It will be an internal leak that will affect the engine’s performance. You will probably not see any oil at the VANOS or drips as expected.