College has gotten so expensive that it’s weighing on even the parents of third-graders, threatening to leave them too debt-saddled to retire.

Tim Williams, a 62-year-old part-time mail carrier from Clearlake, Calif., has spent 12 years paying down a nearly $12,000 loan to help one of his sons pay for college. He now owes more than half that; his monthly payment is about $105. His children and his ex-wife have student debt of their own.

That wouldn’t be a problem if Williams were making the nearly $80,000 he used to earn as a general contractor and union carpenter, but he earns less than half that now, while his medical bills pile up.

The Obama administration, trying to tamp down mounting fears of a student debt crisis, has focused on the upside of student debt, such as its association with a better-educated – and probably better-paid – workforce. But many parents of tomorrow’s college students aren’t listening. They expect paying for college to upend their own retirement plans, according to a new survey by the financial firm T. Rowe Price Group Inc.

Three-quarters of parents of children aged 8 to 14 were willing to postpone retirement to pay for their children’s college costs, the survey of 1,086 households found. About 68 percent of parents said they’d be willing to get a second job, while 69 percent said they favor putting aside money for their kids’ college before their own retirement – a no-no, financial advisers said, warning that such a move could wreak havoc on family finances.