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C4 Corvette Tips and Tricks

Exhaust & Emissions
A/C & Heating
Cooling System Trapped Air Pockets  - Submitted by: redvette89
   A few months ago, I replaced the fuel injectors in my '89 convertible. This was a great opportunity to try a suggestion I had come across a few years ago that solves the difficulty of getting the air pockets out of the cooling system. The cooling system on the L98 engine tends to trap air and refilling the system is very difficult. Some people recommend "stacking the coolant" which is a pain in the arse, or raising the front so it's at least 18 inches higher than the rear (which didn't work for me when I tried it). You can prevent the trapped air problem by simply drilling two little holes in the thermostat flanges. The diameter of the holes can either be 1/16 or 1/8 inch. Over the last 6 years, I have flushed and refilled the cooling system every spring, and each time went through the exercise getting the air pockets out. After installing the new OEM thermostat with the 2 drilled holes, I found the results to be...
  1. Re-filling the cooling system went quicker
  2. Warm up time stayed the same 
  3. Overall, runs about 5 degrees cooler 
  4. Cabin heater blows hotter air (very rare I use the heater, but was noticible when I had the car out last month around Thanksgiving)
Brakes, Steering & Suspension
Care & Maintenance

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