







2017 Chrysler 300 3.6L Pentastar — Damaged Oil Cooler Port on Engine Block — Is This Normal or Impact Damage?
Hey everyone,
I have a 2017 Chrysler 300 with the 3.6L Pentastar V6 (~133,000 km). Recently discovered oil and coolant were mixing, which led us to suspect the oil cooler as the culprit — very common issue on this engine as I've read.
When we removed the oil cooler to replace it, we found something concerning on the engine block itself.
One of the oil cooler line ports on the block has a damaged seating rim — the collar where the O-ring seats is missing a chunk at roughly the 11-12 o'clock position. The seating surface is uneven and clearly not factory condition.
My questions:
Is this a known issue on the 3.6 Pentastar — does this port commonly crack or chip from heat cycling/pressure?
Or does this look like physical impact damage from a previous accident or bad repair attempt?
Has anyone successfully repaired this with a machinist sleeve insert rather than replacing the block?
We used Victor Reinz Reinzosil RTV silicone around the damaged rim before installing the new oil cooler — is this an acceptable temporary fix or are we asking for trouble?
The previous cooler seating from earlier repair has sealent applied all around the port.
Thanks