I have a '98 F-150 with a 4.6L Triton engine. Recently, I took it to the shop because I was experiencing overheating & blow-back of antifreeze. When driving, after starting cold engine, within 5-10 minutes into the drive the temp gauge pegs out for app. 10-20 secs. Then it goes back to normal. When I pulled over, there was massive amounts of antifreeze covering the driver's side tire-well, as well as under the hood. The 1st visit to the shop, they replaced the thermostat. Told me it was ready. I got about 7-10 miles from the shop and it did the same thing. They replaced the new thermostat with a FORD OEM one and still got the same results. Eventually, they discovered a blown head-gasket. Cylinder 6 spark-plug has some antifreeze on it. After, replacing the head-gasket, it's still doing the same thing. Almost like there's an air pocket in the system somewhere. Any ideas?
Friday, February 14th, 2014 AT 12:33 PM