Does high utilization HELOC account hurt the credit score?

[Leeor Neh]

Hi,

If I use a large some of a HELOC account, for ex. using $150K out of $200K, for a few months (say 6 months). Will that hurt my credit score?

I'd pay, on time, the monthly interest-only amounts (~$600 a month). All other credits I have sum to a much lower amount (all the credit cards together ~$20K, so the utilization rate is very high)

I just recently heard from someone that it can destroy my credit score (currently around 760).

My plan was to buy a property using only the HELOC money, rehab it, and then do a cash-out refi.

The concern is that if this can hurt my credit score, then the whole plan is trash, cause I won't be able to do the refi with bad credit.

Thanks!