NO

https://en.wikipedia.org/wiki/Parol_evidence_rule#Overview

The rule applies to parol evidence, as well as other extrinsic evidence (such as written correspondence that does not form a separate contract) regarding a contract. If a contract is in writing and final to at least one term (integrated), parol or extrinsic evidence will generally be excluded.[2] However, there are a number of exceptions to this general rule, including for partially integrated contracts, agreements with separate consideration, to resolve ambiguities, or to establish contract defenses.

To take an example, Carl agrees in writing to sell Betty a car for $1,000, but later, Betty argues that Carl earlier told her that she would only need to pay Carl $800. The parol evidence rule would generally prevent Betty from testifying to this alleged conversation because the testimony ($800) would directly contradict the written contract's terms ($1,000).