diff --git a/src/Elasticsearch.Net/ElasticLowLevelClient.cs b/src/Elasticsearch.Net/ElasticLowLevelClient.cs
index eebfd425021..281faae63f5 100644
--- a/src/Elasticsearch.Net/ElasticLowLevelClient.cs
+++ b/src/Elasticsearch.Net/ElasticLowLevelClient.cs
@@ -75,10 +75,10 @@ public Task<TResponse> DoRequestAsync<TResponse>(HttpMethod method, string path,
 		protected internal TRequestParams RequestParams<TRequestParams>(TRequestParams requestParams, string contentType = null, string accept = null)
 			where TRequestParams : class, IRequestParameters, new()
 		{
-			if (contentType.IsNullOrEmpty()) return requestParams;
+			if (contentType.IsNullOrEmpty() && accept.IsNullOrEmpty()) return requestParams;
 
 			requestParams ??= new TRequestParams();
-			if (requestParams.RequestConfiguration == null) requestParams.RequestConfiguration = new RequestConfiguration();
+			requestParams.RequestConfiguration ??= new RequestConfiguration();
 			if (!contentType.IsNullOrEmpty() && requestParams.RequestConfiguration.ContentType.IsNullOrEmpty())
 				requestParams.RequestConfiguration.ContentType = contentType;
 			if (!accept.IsNullOrEmpty() && requestParams.RequestConfiguration.Accept.IsNullOrEmpty())
diff --git a/src/Elasticsearch.Net/NamespacedClientProxy.cs b/src/Elasticsearch.Net/NamespacedClientProxy.cs
index 3c91daee9ae..91f66f08021 100644
--- a/src/Elasticsearch.Net/NamespacedClientProxy.cs
+++ b/src/Elasticsearch.Net/NamespacedClientProxy.cs
@@ -20,10 +20,14 @@ protected Task<TResponse> DoRequestAsync<TResponse>(HttpMethod post, string url,
 
 		protected string Url(FormattableString formattable) => _client.Url(formattable);
 
-		protected TRequestParams RequestParams<TRequestParams>(TRequestParams requestParams, string contentType = null)
+		protected TRequestParams RequestParams<TRequestParams>(TRequestParams requestParams, string contentType)
 			where TRequestParams : class, IRequestParameters, new()
 			=> _client.RequestParams(requestParams, contentType ?? ContentType, contentType ?? ContentType);
 
+		protected TRequestParams RequestParams<TRequestParams>(TRequestParams requestParams)
+			where TRequestParams : class, IRequestParameters, new()
+			=> _client.RequestParams(requestParams, ContentType, ContentType);
+
 		// ReSharper disable once UnassignedGetOnlyAutoProperty intended to be overridden
 		protected virtual string ContentType { get; }
 	}