Chrysler Repair: 05 Pacifica 3.5L: oil in coolant, coolant tank, transfluid


Question
QUESTION: we have had oil in the coolant for 2 years!Engine light came on at that time.Rad was flushed, new coolant at that time.
We have been putting a liter of oil in approx.every 4-5000km.
We have not experienced any over heating!
Could it be possible that the leak into the coolant is so small as to not effect engine performance? Are we taking a chance driving? We are going to try a sealant but have been told the oil pressure will be to high for this to work.

ANSWER: Hi Paul,
That amount of engine oil consumption is quite low so it may be that there is no cross over of engine oil into the cooling system. Does the engine oil show any cloudiness/foam?
Another possibility is that the transmission fluid is crossing over into the coolant due to a leak between the coolant tank and the trans fluid tank in the combined coolant/trans fluid radiator unit. Have you looked at the transfluid to see whether it shows any cloudiness/foam? What about the loss of trans fluid per 5,000 km, is that noticeable?
Sorry for the delay in responding but I just found your question in the "pool" to which it had been referred by Kevin.
Please 'rate' my answer (see PS below).
Thanks,
Roland

---------- FOLLOW-UP ----------

QUESTION: Hi Roland,

Thanks for your responce.To answer your questions the transfluid is clean looks brand new, so is the oil. I have never notice a loss of transfluid in 2 years.There seems to be a little bubbling in the coolant when the engine is running. My mechanic is suggesting that there is a combustion leak. He cant understand why this engine is running at all! We have had the sealant done and have been driving for a little while.As mentioned before i feel this problem has been around for 2 years.I dont know if we should be as concerned as our mechanic as he feels this engine could blow?
Thanks,
Paul

Answer
Hi Paul,
If the bubbling is found to be exhaust gas (there is an exhaust gas detector which can verify that situation by insertiong a probe into the overflow bottle), then there is a leak between a combustion chamber and a coolant passageway nearby inside the engine and it usually is due to a head gasket leak or perhaps a head bolt that is not up to the torque specification level. That leak is presumably also communicating with an oil passageway, again at the head gasket interface. It must be a small leak to not cause frothing of the oil. I don't know why the mechanic would wonder why the engine will run with this sitaution, so long as the leak is very small. If you tried stop leak treatment that may stop the problem. So long as it doesn't get worse (oil frothng, excessive loss of coolant or similarly loss of oil) I imagine it could run this way as a steady state situation indefinitely until the leak increases in which case the power output from that one cylinder will be noticeably decreased. So try watchful waiting would be a reasonable strategy.
Thanks for the rating/nomination which you can do again for this answer if you so choose.
Roland