C182 PLT NEGLECTS TO REMOVE COWL PLUGS DURING PREFLT. ENG OVERHEATS FORCING A RETURN LAND.

Narrative

I ARRIVED AT SFO; LOADED MY LUGGAGE IN MY PLANE; PAID MY BILL WITH THE FBO; AND CONDUCTED A PREFLT INSPECTION OF MY PLANE. IT WAS DARK; BUT THE FBO RAMP WAS FAIRLY WELL LIT; SO I DID NOT USE A FLASHLIGHT. EVERYTHING SEEMED NORMAL DURING THE PREFLT INSPECTION THAT I CONDUCTED WITHOUT A CHKLIST. I RECEIVED MY IFR CLRNC FROM SFO TO DLO. I TAXIED OUT FROM THE FBO RAMP; AND DID A RUN-UP WHILE HOLDING SHORT OF TXWY C TO ALLOW A B727 TO PASS AS INSTRUCTED BY SFO GND. EVERYTHING LOOKED GOOD ON THE RUN- UP. SFO GND CLRED ME TO TAXI VIA TXWY C TO TXWY E FOR AN INTXN DEP; AND INSTRUCTED ME TO FOLLOW THE B727. SFO GND CLRED ME TO CROSS RWY 28R AND HOLD SHORT OF RWY 28L; AND INSTRUCTED ME TO MONITOR THE TWR FREQ. WHILE I WAS HOLDING SHORT OF RWY 28L; I WAS CLRED FOR TKOF BY SFO TWR. I DEPARTED WITH FULL THROTTLE; MAX ENG RPM; AND FLAPS EXTENDED 10 DEGS; AND COMMENCED THE EUGEN 5 DEP (EUGEN5.SNS) IN ACCORDANCE WITH MY CLRNC. SFO TWR HANDED ME OFF TO BAY DEP. WHILE CLBING THROUGH AN OVCST LAYER WITH BASE AT APPROX 1000 FT; THE CYLINDER HEAD TEMP AND OIL PRESSURE CLBED INTO THE RED RANGE ON THE GAUGES; AND THE OIL PRESSURE DROPPED BELOW THE GREEN RANGE ON ITS GAUGE. I BROKE OUT ON TOP OF THE OVCST LAYER AT ABOUT 1700-1800 FT AND KEPT FLYING THE EUGEN 5 DEP. I CONTACTED BAY DEP AND DESCRIBED THE PROB. THE BAY DEP CTLR ASKED IF I WANTED TO DECLARE AN EMER. I DECLINED TO DECLARE AN EMER BECAUSE THERE WAS: NO ENG FAILURE OR SIGN OF MAJOR ENG OIL RELEASE; NO SIGN OF ENG FIRE; NO LOSS OF MANIFOLD PRESSURE OR ENG RPM; AND BECAUSE THE ENG WAS RUNNING SMOOTHLY. BAY DEP SAID THEY WOULD VECTOR ME FOR AN ILS RWY 28L APCH WITH A TIGHT L BASE; WHICH I ACCEPTED. BAY DEP ASKED HOW MUCH FUEL I HAD; AND HOW MANY PEOPLE WERE ON BOARD. I INFORMED THEM THAT I HAD 6 HRS OF FUEL AND ONE PERSON ON BOARD. BAY DEP ASKED IF I HAD THE SQL IN SIGHT; AND I REPLIED IN THE NEGATIVE AND THAT I WAS ABOVE AN OVCST LAYER. AFTER SEVERAL MORE MINS; I INFORMED BAY DEP THAT THE ENG HAD BECOME ROUGH. I WAS HANDED OFF TO A SECOND BAY DEP CTLR; WHO BEGAN VECTORING ME TO INTERCEPT THE ILS RWY 28L LOC AND CLRED ME FOR MY INITIAL DSCNT. I WAS INSIDE THE BRIJJ LOCATOR OM BEFORE THE LOC NEEDLE BECAME UNPEGGED FROM FULL R DEFLECTION. I INFORMED THE CTLR THAT THE LOC WAS SLOW COMING IN. THE CTLR ASKED ME TO CONFIRM THAT I HAD THE ILS RECEIVER TUNED TO FREQ 109.55; AND I REPLIED IN THE AFFIRMATIVE. A LITTLE WHILE LATER; THE LOC AND GS NEEDLES BOTH BECAME ACTIVE; I INFORMED THE CTLR THAT THIS HAD OCCURRED; AND I CONTINUED TO FLY THE APCH. AFTER BREAKING OUT THROUGH THE BASE OF THE OVCST LAYER; THE SEQUENCED FLASHING LIGHTS OF THE APCH LIGHT SYS AS WELL AS THE RWY LIGHTS FOR RWY 28L WERE IN SIGHT. I INFORMED THE SFO TWR CTLR THAT I HAD THE RWY IN SIGHT. I WAS INFORMED BY SFO TWR THAT EMER VEHICLES WOULD BE STANDING BY; AND I SAW THE FLASHING LIGHTS OF SEVERAL OF THEM TO THE R OF THE RWY. ON FINAL APCH; I HAD A FEELING THAT I HAD NOT REMOVED MY ENG COWL PLUGS PRIOR TO ENG STARTUP; AND SUSPECTED THAT THIS WAS THE CAUSE OF THE PROB. I INFORMED THE SFO TWR CTLR THAT I HAD SUFFICIENT PWR TO ASSURE A LNDG; CONTINUED FLYING THE APCH; AND LANDED ON RWY 28L. I WAS CLRED TO EXIT RWY 28L; CROSS RWY 28R AND RWYS 1R AND 1L; AND TAXI TO THE FBO VIA TXWY C. ONE OF THE EMER VEHICLES FOLLOWED ME TO THE FBO RAMP; WHERE I WAS DIRECTED TO A PARKING SPOT BY ONE OF THE FBO PERSONNEL AND SHUT DOWN THE ENG. I FOUND THAT I HAD FAILED TO REMOVE MY COWL PLUGS DURING MY PREFLT INSPECTION. THIS HAD RESTR AIRFLOW TO THE ENG; CAUSING THE OBSERVED OVERHEATING. I CHKED THE ENG OIL LEVEL; AND FOUND THAT IT WAS STILL AT ABOUT 10 QUARTS; WHICH IS WHAT I HAD DEPARTED WITH. I LEFT THE DOOR TO THE ENG OIL FILTER CAP; THE DOOR TO THE ENG OIL DIPSTICK; AND THE COWL FLAPS OPEN TO HELP THE ENG COOL DOWN. WHILE WAITING IN THE FBO OFFICE FOR ABOUT AN HR WHILE THE ENG COOLED DOWN; I FILED A NEW IFR FLT PLAN TO DLO. AFTER CONDUCTING A THOROUGH PREFLT IN DAYLIGHT; I TURNED THE ENG ON AND FOUND THAT THE CYLINDER HEAD TEMP; THE OIL TEMP AND THE OIL PRESSURE WERE ALL IN THE NORMAL OPERATING RANGE. I SUCCESSFULLY CONDUCTED MY FLT WITHOUT FURTHER INCIDENT. CONTRIBUTING TO THE PROB WAS THE ABSENCE OF MY PRIMARY SET OF DAY-GLOW YELLOW COWL PLUGS THAT ARE CONNECTED BY A CORD; FROM WHICH HANGS A LARGE 'REMOVE BEFORE FLT' FLAG. I USED AN OLD; DARK RED; UNCONNECTED PAIR OF COWL PLUGS THAT I DID NOT SEE IN THE ILLUMINATION FROM THE RAMP LIGHTS. THE WAY TO AVOID THIS IN THE FUTURE IS TO ALWAYS DO A COMPLETE PREFLT INSPECTION USING A PRINTED CHKLIST; AND TO ALWAYS USE A FLASHLIGHT UNLESS IN DAYLIGHT CONDITIONS.