View Full Version : Replacing thermostat -- drill holes?

October 8th, 2006, 08:24
My 1994 4.0L has been running cold lately. It eventually warms up to "normal" (around 210 on the gauge), but during highway driving it hovers around 130-155. Sure, the gauge/sensor could be wonky but I'd rather be safe and just replace the thermostat.

I searched the threads here for some tips and noticed that a lot of the guys with the old RENIX (closed cooling system) 4.0s recommend drilling a hole in the thermostat to allow air to pass through. Is that necessary on my '94 with the open system? The thermostat I purchased has no such holes.

October 8th, 2006, 10:14
no u dont need hole, the hole is to help get rid of air when first installed.