Your technician is wrong. This was a standard practice many years ago
when engines were constructed to loose clearances.

The engine has small passages to distribute oil to where lubrication is
required. These oil passages have been sized to distribute oil flow
approriately with the correct weight oil. If you use a thicker oil, the
oil will flow through the smaller passages slower, thus providing less
or no protection. This will especially be a problem on cold start.

Use the manufacturers recommended oil weight. A synthetic such as mobil
1 or amsoil of the correct weight will extend your motor's life.

Also, change the oil (and filter) at 3000 miles. Extended oil changes
are poor economy because engines are much more expensive than oil.

eh wrote:

> Dear experts,
>
> I have a 98 Accord that has 80K on it. Last week
> I went an independent deader to get my oil changed.
> The technician told me that I should be filling 10-30
> or 10-40 oil since my car has a lot of mileage on it.
> He said these oil protects older engine better.
> The car manual specified to use 5-30 and nothing
> else. Is the technician right?
>
> Thanks,
> Eugene