1999 Honda Civic Head Gasket Replacement

In the winter of 2014 my wife’s 1999 Honda Civic overheated at the end of her drive home from college (about a three hour trip). After finishing up finals, I drove back home and met her at her mom’s house where the car had been moved into the garage so i could look at it. I found a lot signs of how bad the overheat was – the lid of the radiator overflow tank had melted, the label on the oil filter had shrunk to half its size, the valve cover smelled of roasted oil. One of my friends came up from St. Louis for a few days and helped me replace a large number of components and fluids: new radiator, new cooling hoses, thermostat, overflow reservoir, oil change, multiple coolant flushes, and the battery (I think it just happened to die around this time).

After all our work was complete, we fired the car up and it ran fine. However, I figured this wasn’t the last of the trouble – there was no obvious problem I had found during any of our work, nothing that seemed to be the root cause. After returning to school my suspicions were confirmed; the car was low on coolant. From there began a multi-month journey of trying every possible diagnostic method I had available to determine where the leak was. In the meantime, I kept a bottle of coolant in the back of her car and would regularly fill it up (every 3-4 weeks I’d put about half an overflow tank’s worth of coolant in). After trying leak-test dye, radiator headspace exhaust testing, radiator cap pressure testing – nothing turned up any obvious results. Everything pointed to a small leak between the cooling jacket and a cylinder, but small enough that my radiator headspace test didn’t turn up anything.

However, her car kept running, it just needed a bit of coolant every now and then. Fast-forward to December 2014. I take a job at Southwest Research Institute, we move to Michigan, and her car keeps on trucking. Finally, this summer I had to decide between selling the car or replacing the head gasket. I choose the later and below is a gallery providing an overview of the process. Before embarking on this project i had no experience in this sort of major automotive repair. I printed out roughly 40 pages of service manual information, watched numerous videos from Eric the Car Guy, and called numerous friends and family members with automotive experience.

The job in total took three weeks, a bit longer than I anticipated but twice I unexpectedly had to order parts (see the timing belt cover photo below). However, in the end, the car fired up and ran. I learned a lot in the process, and gained a decent amount of confidence in my auto tech abilities along the way.

Update (2017-07-15): The car ran without needing a drop of coolant for two years! While the car has been a good learning experience (since this post I’ve replaced roughly half the exhaust system, the power steering rack, and bled the brakes), I was definitely glad to finally sell it and upgrade to something a bit newer.