Have a terminator cobra with very low miles (5000) that has an odd issue. The engine starts ticking at 210F coolant temp (normal operating temp), and only at idle. No tick is heard on cold start, but once the car reaches 210F coolant temp you can hear the tick start, but again only at idle. Give it a little gas to reach 1000 rpm, and the tick noise is gone. Gotta stick my ear down by the passenger side fender well to hear it. Noise is not heard inside the cabin of the car. Sounds like tick tick tick, tick tick tick, tick tick tick, tick tick. Then it repeats over and over again the same way.
Taking her out for a 30 minute drive, and then doing the following...
Running the engine at 3500 rpm for 3 minutes @ idle, and getting the coolant temp up 230F makes the noise temporarily go away. The coolant temp can cool all the way back down to 210F after the 3 minute run, and kick the fan off, and I won't be able to hear the tick. But let it cycle the fan a few more times, and the tick will return.
It isn't the lifters/lash adjusters as I had them replaced. I'm thinking maybe a piston issue since they will expand further when getting warmer then normal operating temp. Definitely not a rod knock as those gets worse with higher temps, and do not go away with additional heat like mine does.
Anyone have any ideas what the issue could be? Anyone ever experience anything like this? Thanks.