863903A03 Mercruiser Heat Exchanger - 3.5 inch diameter
This is Not an Original Equipment Manufacturer (OEM) Part.
Days to Ship: Ships Today
Note:If it says “Ships Today” Orders placed M-F before 4pm Eastern Time will ship the same day. Orders placed after 4pm and on weekends will ship out the next business day.
Offered is our replacement for the Mercruiser 863903A03 Mercruiser Heat Exchanger - ID of... Read More
Offered is our replacement for the Mercruiser 863903A03 Mercruiser Heat Exchanger - ID of appx 3.5" diameter with OD of about 3.75 inches. This includes the heat exchanger, end caps with gaskets and the OEM seals that are used in the crossover. This part is made with OEM equivalent materials and is guaranteed for fit and function.
A while back we decided to include the OEM seals for the crossover. The seals tend to take a set or get a little brittle over time and you could end up with a glycol leak where the heat exchanger presses into the crossover if you try to re-use the existing seals. In addition, each heat exchanger is made using a fixture and checked for fit to the crossover dimensions prior to shipment to confirm that there will be no fit issues interfacing with the crossover.
There is a 3.5 inch version and a 4 inch version. The change over from 3.5 inches to 4 inches occurred around the 2006 timeframe. You may want to take a look a the pictures to see which one you have. It's a simple measurement. It is our experience that a 3.5 inch version cannot always be replaced by a 4 inch version. There are special instances when it works, but for the most part if you have a 3.5" version, replace it with the 3.5" version. 4 inch replaces the 4 inch. If you want to assure you're not going to experience interference issues order the part you currently have on your boat.
Some details to note:
863903A03 is a 3.5 inch part -
You are reading the advertisement for the 3.5 inch model.
a 3.5 inch inner diameter part has an OD that is approximately 3-3/4" to the outer diameter.
Inner diameter of the shell is very near 3.5 inches.