Using Low Gears On Automatic Car Bad For The Engine

Posted in Crank, Oil and Piston | Asked on Jul 4, 2010

We have a Totyota Corolla (can’t remember which year, but in the last 10) and recently the engine has become a bit noisy (few rattles and some purring). My stepdad says it’s because my mother “ruined the car” by using the lower gears to get up the steep hills between my aunt’s house and ours. He says it could damage something called a connecting rod. I have searched and have found nothing to support this, so I was just wondering if any one of you master mechanics could back it up. Anyone ever heard this? Because my mother was taught by her father (who was handy with cars himself) that it was okay to use and even necessary for a little car to negotiate a big hill.
Who’s right? My grandfather or my stepfather? Did my mother really ruin the engine?
Actually I don’t know how old the engine is. We had to put a new (from a pick’n'pull- a lady totalled her car, but the engine was all right) one in it after some mechanic effed up an oil change and the oil leaked out and the engine burned up.
The engine was a few years younger than the original engine, but had the same basic mileage. It was also a Chevrolet engine. Does this make any difference?
She’s overdue for an oil change. She’s been complaining of poor gas mileage as well as the noise, and I’ve told her to get on it. She keeps saying she has to time. I tell her, ‘well, pretty soon you’re also going to have no car.’
From what’s being written here, I think THIS is the source of the problem rather than just her downshifting. She is still killing the car, just not exactly the way we thought. Thanks all. We’re working on her.

There are 13 Answers for "Using Low Gears On Automatic Car Bad For The Engine"

  1. ricardo9505 says:

    I’m laughing. Connecting rod with lower gears. Makes absolutely no sense to me. Lower gears were created for just that, going up/down hills. Hell my cousin uses it to tow with his BMW (not often). I use lower gears in traffic to dip/dive. Many new cars were engineered to drop constantly from 4th to 3rd. The purring seems ok, isn’t that what an egine is supposed to do.

    my God, the engine is 10 years old and something could be wrong? God forbid!!
    sarcasm

  2. nemocamaro says:

    as long as she kept the rpms around 4k, she should have been fine, it depends on exactly what she did. for instance, if she kept the car in first the whole time, then yea, she did something bad, but you do need a low gear to get up a hill, it is just simple physics.

  3. uthockey32 says:

    No she did not ruin the motor. You can use low gears to climb hills that is what they are for, you do not want to drive all day at high RPM’s but it will not hurt the motor to climb a hill. After 10 years it’s normal for a motor to make some noise, just make sure you keep the oil changed and do any maintenance the car needs and it will go an other 10 years.

  4. Guy says:

    its fine to use the lower gears when climbing hills, thats what they are there for. the only thing is when climbing a hill in a low gear is to not get the RPM’s of the engine up to high or you could over speed the engine.

  5. bandit_60 says:

    it won,t hurt it. that,s why the lower gears are there for. it can hurt it if they gear down going too fast.

  6. friedach says:

    If the hill was steep, and she carried 3+ adults or similar weight and she drove quickly then there might be something to it. Conrods don’t bend unless you REALLY rev the motor hard. Being an auto, it would select lower gears on steep hills anyway. A manual would be able to travel quicker for less revs. and less fuel. That said, the motor would be running hotter than an manual, because of the power lost in the transmission, and that would seriously affect the motor life. If the motor was run hard whilst cold, that would be very bad for it. Price you pay for a small auto in adverse conditions I guess. Did he ever drive that route and if so, what did he do differently?

  7. Nomadd says:

    Your dad is full of it. It’s a lot worse lugging an engine in too high a gear than shifting down. Anything short of 70% redline isn’t going to cause any trouble.

  8. the lock man says:

    getting an engine from pick n pull was probally the real problem-since you have no idea of the actual history of the engine….blaming mom is pretty weak….and no she probally didnt hurt the engine..

  9. Alekat says:

    YES! It can be bad.

    Unless the engine is kept under load, during high RPM’s in a lower gear, the connecting rods can slap the crankshaft bearings and/or crankshaft bearings can slap the main bearings- – -IF – - there is insufficient bearing cushion. Bearing cushion comes from proper viscosity oil AND proper bearing clearance. If the bearing clearance is excessive, (normal on high mileage or poorly maintained engine lubricant), it is possible to “rattle” .

    It is best to leave an “automatic” in drive and it will automatically select the proper gear according to hill incline.

    Believe it or not.

  10. STEVE R says:

    of course your mother use of low gears, going up a hill are no problem. Your problem seems to be your step-father & your mother, as my children grew such, please believe me, 10 years later, all my 5 kids still love me, the father. They have problems today, as she lives 5 states away. luv ser

  11. chris at hornchurch says:

    you answer own question in reality. since the lower gear usage wont hurt an engine just burn fuel it was the instance where you state the engine lost oil and ‘burned itself up’.
    when any engine gets overheated by loss of water and especially oil it will cause problems as gaskets and parts can warp and get damaged.
    the real problem is the engine has suffered damage from overheating and needs to be exchanged before it fails.

  12. don r says:

    You can use lower gears to climb steep inclines when you don’t want to keep accellerating to excessive speed. Use 2nd gear up to about 40 MPH. Use 1st gear under 25 MPH. When you rev an engine too high you can cause exhaust valves to burn or if extremely high revving, you can bounce the valves off their seats so they strike the pistons and get bent.

    When you change an engine, sometimes heat shields get deformed in the rough handling of pulling and transporting the engine. They can rattle and buzz. More seriously though, failing to keep sufficient oil in the engine can allow premature wear.

    The poor gas mileage can result from running in low gear- running the engine at higher speed while gaining less distance. Check the tire pressure too. Soft tires can waste economy from increased rolling resistance.

    If your mother doesn’t take time to maintain the car with at least oil changes, I’d expect other neglect such as needing a tune-up, fresh air filter and who knows what else. The shop prices for this are scary, but I bet not as scary as needing another engine.

    Insufficient and dirty oil can ruin the connecting rod bearings, and the higher you rev the engine, the sooner one will fail and a rod will go bye-bye thought the oil pan.

  13. Ozeki says:

    no, grandpa pa is wrong. tell him.