This may be pricey to fix some models had an external oil cooler in the radiator as with automatic transmission lines, others had one in the block itself..they were steel lines subjected to vibration and rust..only other thing I know is maybe a failed freezeplug under the valvecover somewhere or in the inake assembly..ultimately you may have a cracked casting somewhere and those arent easy to find.. good luck
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This may be pricey to fix some models had an external oil cooler in the radiator as with automatic transmission lines, others had one in the block itself..they were steel lines subjected to vibration and rust..only other thing I know is maybe a failed freezeplug under the valvecover somewhere or in the inake assembly..ultimately you may have a cracked casting somewhere and those arent easy to find.. good luck