I have a 1997 Honda Civic with 268k. It runs well although it lacks the pep it used to have. Recently I was told that my compression is only about 110 on each cylinder, while it should be 135-180, and that this is normal for a high mileage car. So, is my car dying? If so, how long does it have to live? Could it last months or years like this or will the compression continue to get worse?
Yes, your engine is likely losing compression due to normal wear, but cars don’t “die” from gradual loss of compression. They die because of a broken timing belt, rust, overheating, leaking head gaskets, or other crises.
You may still get a few more years out of it, but it’s definitely getting long in the tooth, so start saving for a replacement vehicle.
It could last until tomorrow or another 200K - it is impossible to say.
To aid your chances that it could last, maintain it well and don’t beat on it to much.
Back in 1961, I bought a 1947 Pontiac for $75. The engine used a quart of oil every 150-200 miles. The cluster gear in the transmission was worn and it made an awful noise in low gear. However, I made the 350 mile trip to graduate school and ran the car for a year without problems. We didn’t have much in the way of interstate highways in those days. I kept the speed under 60 mph, shifted out of first gear as soon as possible, and drove it gently. Two years after I sold the car, it was still running the streets.
Follow the advice given by Chevrolet in an ad I saw in Time magazine in a late 1945 issue. The ad explained that there would be a shortage of new cars even though production of new cars had resumed. The ad went on to say “In the meantime, continue to conserve your present car”. If you do this, your Honda may go quite a while longer.
Loss of compression is due to wear on the piston rings and can also indicate valves either with worn seats, carbon build up, or out of adjustment.
The only real fix for worn piston rings is an engine overhaul which will include new rings and lot of other wear items get replaced as well. You can have your valves adjusted and see if it helps. Carbon build up to the point of compression loss usually means pulling the head and manually removing the carbon. At that time the valve seats and valves can be ground and be “like new”.
So, if you want to spend a couple of hundred dollars you can have the head removed, cleaned, valves and valve seats ground and put it all back together. If the compression comes back to normal you are good to go. If the compression is still low, then you are looking at a motor rebuild.
Worn piston rings should produce some blue exhaust smoke at times and you’d also be burning some oil, like 1qt. every 1000-2000 miles. No smoke and no oil burning - then the head pulling and valve job might be worth a try.
It could live for years like this…assuming you check and maintain the fluids regularly and fix whatever breaks when it breaks. At some point the safety related systems like the brakes or the body intergrity (think: rust) will get so bad that the car will become unsafe. Or the compression will drop so low that you can’t keep up with highway traffic anymore. Or it’ll start using so much oil that you’ll get tired of putting it in.
I persoanally am not an advocate of rebuilding a buggy like this. I’m an advocate of keepin; on keepin’ on until either the car becomes unsafe, the constant oil replacement becomes untenable, or your needs change and you need to get something else anyway.
start looking around now for a new ride. That way you have an idea of what you want when it DOES give out on you. This will save you from the panic mode you’ll likely encounter if something happens AND it’ll save you money as the salesmen can usually spot desperate buyers a mile away.
You should be on your third timing belt. If its still on its second, it may not be worth the cost to put a new one in, but if you are on your third belt, I suggest that you check the valve lash. You low compression could be due to the lash closing up on you, or opening up too much. Get that right, then think about using a thicker oil, 15w40 should help some.
My recommendation for 15w40 is based on the assumption that you are now using 10w30. If you are currently using 5w30, then switch to 10w30 on the next oil change.
Dump a can of “Restore” in it and keep your eye out for another car…
If the engine still starts well, especially when hot and runs smoothly and isn’t fouling the spark plugs, you have a little time left. I have a lawnmower that started putting out blue smoke and didn’t have the power it once had, but still ran well. However, it was fouling the spark plug and was difficult to start when hot. One time I had stopped the mower when it was hot and it didn’t want to restart. I reasoned that if I pulled the cord a little faster, the magneto would generate a hotter spark and the mower would start. Well, it did work, but I pulled a muscle in my shoulder in the process. At that point, I bought a short block and rebuilt the engine. Now the mower was worth rebuilding since it has a cast aluminum deck that doesn’t rust. I was amazed at how much more power the mower had after the new short block and how much less gasoline it used.
Now, your Honda is at an age where it may have some chassis rust. It also has a transmission which the lawnmower doesn’t have. Use the time your Honda has left to scout out a newer ride. After 268,000 miles, it has earned its retirement.
I would be willing to be that your car doesn’t run as well as you think it does because you have become acclimated to anemic. Drive another 97 Civic with good compression around for a few days and then jump back into your car. Odds are that you will find it horrible.
At 110 on the compression the motor is approaching the end so just run a thicker oil and drive it to the end.
By the way, whoever told you that 135 PSI compression is good is also dead wrong. Those kinds of numbers are pulled from many service manuals and I can’t explain why many manuals are so often incorrect and it’s not just the hokey manuals such as Chiltons and Haynes either.
I’ve got some factory Subaru manuals that state 124-136 PSI compression is normal and that is utter, teetotal bunk.
Low compression numbers are published to avoid engine replacements while the car is still under warranty…Just like burning a quart of oil every 1000 miles is “normal oil consumption” for a new car…