This is for newer model years - might be relevant.
INDMAR - SERVICE BULLETIN
Service Bulletin: SB2012-3IN
Date: June 13, 2013
Subject: Required Water Flow Change 2012 and 2013 Model 6.0L (L96) and 6.2L (LS3) Engines
Units Affected: 2012 and 2013 Model L96 (6.0L) and LS3 (6.2L) engines with Tube in Tube Exhaust Manifolds and 7 Digit Serial Numbers Before Serial Number 2249300
There have been some reports of these exhaust manifolds and hoses exceeding recommended temperature. Indmar has identified an approach to resolve this issue. The first step is to change the thermostat housing and reroute the water flow through the cooling system.
Indmar Has developed cooling system modification kits for these engines. The kits are as follows:
6.0L (L96) Engines with V-drive Transmissions P/N 495181V
6.0L (L96) Engines with In-Line Transmissions P/N 495181I
6.2L (LS3) Engines with V-drive Transmissions P/N 495182V
6.2L (LS3) Engines with In-Line Transmissions P/N 495182I
What You, The Dealer Should Do:
1. Modify all of the units that you have in your inventory prior to delivering the boat to the end user/consumer.
2. If a boat has been retail delivered, immediately contact the affected customers to whom you have sold boats and have them bring their boat in for modification.
Warranty Claim Process for SB2012-3
Flat Rate Allowance 1.5 hr
System Code 527
Failure Code 042
Include photo verification as directed in the work instructions and the Serial Numbers of engines you have modified per SB2012-3 and on the attached warranty claim and send them to email@example.com
Contact Indmar for Instructions on the plumbing modifications.
5400 Old Millington Rd.
Millington, TN 38053