Auto Repair Shops questions, answered straight

The questions below are the ones drivers ask right before they hand over money — and the ones the internet answers worst. Most of what comes back is a lead form or a sales page. These are plain answers with nothing to sell.

• What are the symptoms of a failing catalytic converter?

  A flashing check engine light is the sign AAA says not to keep driving on. What a catalytic converter does, the symptoms shops look for, what the EPA requires of a replacement, and what RepairPal publishes for the part.

• What are the first signs of a blown head gasket?

  Oil and coolant mixed together is the sign RepairPal names first. What a head gasket does, why overheating causes and follows it, what gets mistaken for it, and what RepairPal publishes for the repair.

• Can I drive with a coolant leak?

  AAA's guidance for an overheating engine is to pull over, turn the engine off and call roadside assistance. What a coolant leak does, why topping it up and driving on is the thing AAA warns against, and what the repairs cost.

• Can I drive with a bad CV axle?

  RepairPal says there is no set timetable once symptoms appear and to replace it as soon as possible, because of how severe a failure is. What a CV axle does, what the symptoms sound like, and what the repair costs.

• What are mechanic labor rates?

  A labor rate is the hourly figure a shop multiplies by the hours a flat-rate guide gives for the repair. What AAA publishes about how those hours are set, why the technician does not keep the rate, and how diagnosis is priced.

• How much does a mechanic charge per hour?Costs

  Almost half of all auto repair shops price labor between $120 and $159 an hour, per AAA. The published state table, what a flat-rate manual is, why the dealer costs more, and how to read the labor line on your estimate.

• Do auto repair shops offer payment plans?Costs

  Some shops offer financing and NerdWallet names six ways to spread a repair bill, from pay-in-four to a personal loan at about 7% to 36%. What each one costs, the deferred-interest trap, and what to ask before you sign.

• How much does it cost to fix a transmission?Costs

  RepairPal publishes $6,166 to $6,685 for a transmission replacement and $282 to $343 for a fluid change. The four jobs the phrase covers, where the money goes, and why AAA's figure is lower.

• How much does it cost to fix a transmission leak?Costs

  RepairPal publishes $498 to $646 for a trans oil pan gasket replacement — the common source of a red puddle. What the labor and parts split says, when a leak turns into RepairPal's $6,166 job, and what to check first.

• How much does it cost to fix car air conditioning?Costs

  RepairPal publishes $283 to $366 for an AC recharge, $833 to $978 for a condenser and $1,058 to $1,447 for a compressor. Which repair you actually need, and why a recharge alone can be money thrown away.

• How much does it cost to replace a CV axle?Costs

  RepairPal publishes $1,282 to $1,381 for a CV axle replacement, with parts at $1,075 to $1,077 and labor at $207 to $304. Why the part is most of the bill, and why RepairPal says not to buy a rebuilt one.