Head Gasket? 2005 kia sorento
foamy residue on oil cap, but not on dipstick. just did timing belt, water pump, crankshaft sprocket, harmonic balancer and assorted gaskets and seals. it also throws an upstream 02 sensor code and cat code. 2005 kia sorento has 284 thousand kms on it. 4×4 full time. also has a misfire.