Backstory: I'm the original owner of this 03 Civic EX with the 1.7L VTEC. Back in 04 and 05 I did a couple of UOAs which looked good. We got busy starting a family and doing UOAs kind of got put on the backburner. Fast forward to 2020 and I decide to do another UOA on this car, which I'm still driving daily. I'm now living in a different state and my driving has gone from high mileage highway driving to low mileage short trips -- from 15k miles a year to 4k miles a year. I had no hint that there was an issue, so the timing was good. A coolant leak was detected. I took it to the shop and confirmed, then got the HG replaced. Drove it 500 miles and took a sample to confirm the HG was no longer leaking.
If anyone's interested, the first two UOAs on this sheet were Pennzoil Conventional 5w-20. The third one where the coolant leak was detected was Pennzoil Conventional High Mileage 5w-20. The current one with 517 miles is Supertech Full Synthetic High Mileage 5w-20, which I left with the shop doing the head gasket work. I'm trusting they used it.
I'm currently driving with a mix of 93% Pennzoil Conventional High Mileage 5w-20 and 7% Motorcraft 5w-20 Synthetic Blend (what I happened to have in the garage that got me to 3.5 qts). I plan on doing another UOA at 1000 miles, then switching back to Supertech Full Synthetic High Mileage 5w-20 with FRAM XG filters. Assuming a good UOA on the next sample, I'll go back to 2x-year oil/filter changes. With almost exclusive short trip driving, I'm comfortable with ST HM Full Synth + FRAM XG filters twice a year, about every 2000 miles. This baby has been good to me for nearly 18 years and I plan to treat her well for whatever time I've got left with her.
If anyone's interested, the first two UOAs on this sheet were Pennzoil Conventional 5w-20. The third one where the coolant leak was detected was Pennzoil Conventional High Mileage 5w-20. The current one with 517 miles is Supertech Full Synthetic High Mileage 5w-20, which I left with the shop doing the head gasket work. I'm trusting they used it.
I'm currently driving with a mix of 93% Pennzoil Conventional High Mileage 5w-20 and 7% Motorcraft 5w-20 Synthetic Blend (what I happened to have in the garage that got me to 3.5 qts). I plan on doing another UOA at 1000 miles, then switching back to Supertech Full Synthetic High Mileage 5w-20 with FRAM XG filters. Assuming a good UOA on the next sample, I'll go back to 2x-year oil/filter changes. With almost exclusive short trip driving, I'm comfortable with ST HM Full Synth + FRAM XG filters twice a year, about every 2000 miles. This baby has been good to me for nearly 18 years and I plan to treat her well for whatever time I've got left with her.