LT1 Oil in Coolant
 

My '95 LT1 has for some time accumulated a slight amount of engine oil in the coolant. This engine has 108M miles, the water pump and opti have been replaced at about 100M and the only modification is a Hyper-tech program and 160 Therm. ....Standard transmission, not automatic. It seems to be a very slight leak as the oil level between changes shows no significant drop. There is no cross-over coolant to oil so I'm ruling out a blown head gasket. Question: what is the likely source? And given the car runs like a top should I ignor it and just flush the coolant periodically?

....also, how many miles you guys get on those spark plugs? Mine are still original.

I had the exact same problem a few years ago. It turned out to be the oil cooler. I had it removed it and flushed the entire cooling system a few times. Hope this helps

The original AC Delco platinum plugs had a tendency to lose the little platinum pucks off one or both electrodes. If you have 108K miles on the original plugs, you are on borrowed time. Lose one puck and you have an 0.070" gap, lose both and you're at 0.090" and the spark will start crossfiring to an adjacent wire, because the plug gap is too big.

.......thanks for the feedback guys. Sleepy Z, tell me more about removing the oil cooler. Did you replace, repair or? Happy 4th Patriots!

In addition to the oil cooler, you could have a bad head gasket or warped craked head if I'm not mistaken. Hope for your sake its not the latter. Good luck.

Oil in Coolant........
 

I found this.....interesting (water pump just replaced) source of oil in coolant?? Sounds better than a cracked head!!!!!

"The water pump on these engines is driven by a small shaft off the camshaft gear. This improved cooling reliability (no belt to slip or fail), but it also creates a potential leak path for oil. The water pump driveshaft seal typically leaks once the engine has about 60,000 miles on it. The fix is to replace the seal, which takes about two hours and requires a special tool (J39087) to install the seal. The tool prevents the lips on the seal from deforming when the seal is installed. If you don’t use the tool, chances are the new seal will leak — and you’ll have to do the job over again! "

I had a mechanic remove the oil cooler. I couldn't find the problem & everyone I talked too said I had it backwards.

The water pump drive shaft seal in the timing offers a path for oil to leak out of the timing cover, not into the water pump.