: Oil in Coolant

08-23-03, 12:06 AM
have a 95 STS , a few days ago I noticed oil coming out of the overflow from the coolant tank, I checked the oil level and had to add 3 qrts to bring it up, i started the engine with the radiator cap off , and got a steady stream of oil, any ideas of which direction I need to start to find this problem, Thanks Tim

08-23-03, 12:59 AM
Oil in the coolant is not good news.

There are a limited number of ways oil could get into the coolant in a NorthStar engine
1) Somebody added oil in the wrong place (it can happen)
2) Crack in the head allowing pressurized oil to leak into the water jacket
3) Crack in the block...
4) Bad headgasket - the pressurized oil passages to the camshafts cross from the block to the heads at the front (pulley side of the engine). The oil pressure typically will be higher than the coolant pressure. A blown head gasket (or pulled head bolt threads) could allow the oil to cross over.
5) Cracked engine oil cooler in the passenger side rad tank.
6) Cracked transmission oil cooler in the driver side rad tank. (if the "oil" reddish?)

Good luck.

08-23-03, 08:52 AM
I'd vote for the oil cooler myself. It's actually fairly common, especially if the radiator or oil cooler lines have been replaced recently.