Replaced the plastic intake (was leaking at thermostat housing) with dorman unit on my 99 GT 4.6 litre with 78K. The replacement went well with no issues. Upon start-up the motor is making a loud tick or knock. Removed intake and scoped the intake runners and piston via the sparkplug holes and see no damage (such as if something had fallen in during install). Also compression test on each cylinder showed positive results. (all between 150-160 psi). I am am confident I have the right PI stock replacement intake. The knock gets more prounounced as throttle is increased. Removed the serp belt and the knock is still there when the motor was run momentarily (to see if the water pump or an accessory was the culprit). Other than the knock the motor starts, runs smooth with no hesitation or miss. Can't tell where the noise is coming from (top or bottom, left or right bank, etc).
I have uninstalled and reinstalled the replacement intake twice with the same result of the knock...have not tried to put on the old unit to see if the noise is replicated yet.
Any ideas on what direction to go in now? Thanks in advance for your help...
David
I have uninstalled and reinstalled the replacement intake twice with the same result of the knock...have not tried to put on the old unit to see if the noise is replicated yet.
Any ideas on what direction to go in now? Thanks in advance for your help...
David