Ok so I swapped out all my hoses and Tstat, and put in fresh coolant. Now when I drive the car around for a lenght of time and pull off the radiator cap, there is a layer of oil underneath. First I thought it was residual rust, or oil. But I siphoned it off a couple times, and it keeps coming back. First thought was s#!t its a head gasket. But there is no coolant on the dipstick from what I can tell, no coolant smell in the exhaust, and the car runs nice and cool. Coolant level seems to be steady, so I'm not losing any from a crack in the heads or block. I never noticed this before, so from what I can tell its only started since I changed the coolant. Could a pocket of air or something caused a gasket somewhere to spring an oil leak - I know on the 2.8 the timing cover and water pump share bolts, could it be coming from there (didn't touch the water pump btw during my maintenance)? Any ideas? Thanks!

 

Wouldent worry too much. Its easyer to get coolant in the oil then vise versa. Most likely your engine is fine, probably just spilled some oil in the antifreeze or had some crap floating in the old stuff still in the block.

I'd change it again, this time purchase a prestone flush kit and follow the directions. Replace the radiator cap and then check it.

 

If it were mixing- like ssc stated- you'd have coolant in the crankcase. It would make the oil look like a milkshake.

 

Right, and thats definitely not the case, oil is looking crystal clear.

So how can/should I go about solving this? Any ideas where it might be leaking into the coolant from?

 

TTT, anyone else got any ideas?

 

HHRA, in case you missed this suggestion? Thought this was answered well. There is no way that oil is leaking into the coolant system without the reverse happening 10 times sooner. Pressure does not work backwards.

 

Starting from scratch with fresh fluids really is the wise alternative.
Believe me, you'd know if ya had the chocolate milk shake going on under your hood! If it happened to ya once, you'd know if that is your problem & sounds like oil & water mixing in crankcase is not the problem

 

Alright, thats quick and simple enough to troubleshoot so I'll just drain the coolant and refill again. I just wish I could figure out how the oil got there in the first place!

 

Don't just drain it, then refill it.- FLUSH THE SYSTEM.

 

Yep, you must flush it well as when you drain the water. The oil will just stick inisde and not ocme out. But a little oil in it does or will not hurt anything. Actualy it will provide a splash of lube for the bearings.

I often thought of putting some water soluable oil in there to lub the pump but also keep the block and radiator clean from scale build up.

I would not even worry about it or waste the money changing it. Not unless you reallythink its a blown gasket. The oil will not hurt anything.

Matt

 

Do you have an automatic ? It could be transmission fulid from the built-in trans. cooler in your radiator.

 

That thought actually had crossed my mind too. Checked trans fluid and it didn't look low, and was still pink (I changed it only a few thousand ago). I actually poured a little trans fluid in a sample of coolant, and it still looked clearly pink on top of green coolant, whereas the coolant w/oil I siphoned off was a brownish black on top of the green coolant.

 

Isnt likely a bad or broken trans cooler tank either. If that were the case when your cooling system got to operational temprture and a crack would open from pressure coolant would be forced into the transmission because theres more pressure in the cooling system then in the trans cooler.

That $8 flsuh kit avalible at Wallmart and everwhere is looking mighty good still.

 

Take the the radiator out & have pressure checked at operating temp. The 92 Bonnie I had for a little while had a plastic radiator. When pressure checked it ws fine, but when heated up, plasic would expand & the fluids mixed. Killed the clutch paks & rusted up teh tcc. $1800 job. fwd suks in that regard.