- Oct 6, 2006
- 12,150
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
Here is yet another heads up for owners of early 8.1 liter Mercruiser engines with aluminum manifolds that are run in salt water. These are aluminum manifolds with tubular stainless steel risers. Both the riser and manifold are sea water cooled even if the boat has FWC.
We had hoped to see the need to check manifolds and risers decreased when the 350 and 454 cid Mercruiser engines were phased out, but that does not appear to be the case. I saw 3 different boats with 8.1's and aluminum manifold failures last week in Florida. The years affected seem to be about 2003-2005 or up to the time Mercruiser stopped using aluminum manifold castings. Failure can either be external where a hole corrodes thru to the outside or internal in which case the engine is lost usually due to internal corrosion and hydrolocking.
The recommendation is to remove and check both the risers and manifolds immediately if you have aluminum castings. If there are signs of corrosion, go to your dealer and ask them to contact Mercruiser for you and that you want the manifolds replaced with later cast iron ones.
This is apparently another one of Mercruiser's "super double secret recalls". They are not advertising the problem and have not contacted dealers with a recall notice, but they are repairing some affected boats at no cost to the owner if the owner handles the repair thru a dealer who goes to bat for the customer. In one case last week, Mercruiser paid for a haul out and replacement of the port engine on an '04 390DA, long out of warranty, so it is worth seeing your dealer if you have a suspect boat.
We had hoped to see the need to check manifolds and risers decreased when the 350 and 454 cid Mercruiser engines were phased out, but that does not appear to be the case. I saw 3 different boats with 8.1's and aluminum manifold failures last week in Florida. The years affected seem to be about 2003-2005 or up to the time Mercruiser stopped using aluminum manifold castings. Failure can either be external where a hole corrodes thru to the outside or internal in which case the engine is lost usually due to internal corrosion and hydrolocking.
The recommendation is to remove and check both the risers and manifolds immediately if you have aluminum castings. If there are signs of corrosion, go to your dealer and ask them to contact Mercruiser for you and that you want the manifolds replaced with later cast iron ones.
This is apparently another one of Mercruiser's "super double secret recalls". They are not advertising the problem and have not contacted dealers with a recall notice, but they are repairing some affected boats at no cost to the owner if the owner handles the repair thru a dealer who goes to bat for the customer. In one case last week, Mercruiser paid for a haul out and replacement of the port engine on an '04 390DA, long out of warranty, so it is worth seeing your dealer if you have a suspect boat.