My 06 Chrysler 300 had oil going into the radiator. The shop is telling me the engine is holding pressure and are ruling out a blown head gasket. Also said the oil cooler is holding pressure as well. What else could cause this problem?

Asked by Sep 04, 2015 at 11:09 PM about the 2006 Chrysler 300 Limited

Question type: Maintenance & Repair

Oil mixing with coolant.  Engine did not run hot nor was there any thick smoke from the exhaust.  Engine and oil cooler are holding pressure.  What would cause this problem?

9 Answers


Automatic transmission fluid. If you have a transmission fluid cooler in the radiator (most automatics do) it's probably leaking. The "oil" that your seeing is most likely automatic transmission fluid. HTH. -Jim

2 people found this helpful.

yes is ony in the over flow tank??if so just flush it out and check it again in a few days!!!

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Intake leak, casting flaw in the engine block, engine oil cooler if equipped, as mentioned above internal leak in the radiators transmission cooler, cracked cylinder head. HTH

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Hey I have a Chrysler 300 3.5 2007 Railroad Drive and I did a transmission change and forgot to put the top back on after I was done I took off to go test it out and transmission fluid came from the top of the transmission hose on top of the car and flooded and got all over the engine but after that I have found oil or transmission fluid or whatever it is and my Chryslers coolant Reservoir I flushed it out but it's still a little bit in there I don't know how that got up in her help anybody please car not overheating no white smoke not a head gasket I think


Transmission fluid will be red and will show red in the coolant, engine oil will be black and will show black in the coolant. If it's red then you have a crack in the trans cooler inside the radiator, so the radiator will need repalced or the cooler completely bypassed and a auxiliary cooler installed. If it is black then it is a blown headgasket or cracked cylinder head, they don't all blow white smoke if a headgasket goes bad, but that is the most common symptom.

2 people found this helpful.

Brown and milky and it's not running hot


At this point I would have it power flushed too get it all out, needs to be throughly cleaned, then you will have fresh fluid, watch it everyday before intial start of the engine, if the color starts to change or drop then you definantly have an internal engine problem.

1 people found this helpful.

I flushed it and everything it came back but I don't understand why I was reading up incense in about a oil radiator I looked up for the 3.5 Chrysler 300 2007 it's it's under a car by the oil filter


Do you know what style of oil cooler you have, is it just a fin type of cooler or does it have coolant hoses attached to it. If it has coolant hoses attached there have been some issues with them leaking internally. You could bypass the unit, then do another good flush and see if it stays clear, (just temper your driving as the oil will no longer have a cooler) if it does then you have found your leak, if it gets bad again then it's time for an engine tear down to find the problem. I remember an engine that every place it went they could not find the coolant leak into the oil, it had been to 15 different shops, then it came to mine, no one had even come up with the idea to start tearing it down to find it, well I found it with 45 minutes the block had a pinhole in the valley under the intake manifold, had the blocks leak "pinned" and that was that put it back together cleaned it up and bye bye coolant leak. So you never know where a leak might come from if all the obvious places have been eliminated.

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