• Offered is our replacement for the 99356A1 Power Steering Cooler.   This is commonly found under the motor and was used for small block and big block motors too numerous to mention for 10 years.  
• This offer includes only the power steering cooler.    
• This part is made with OEM equivalent materials and is guaranteed for fit and function.
• 99356A1 was used with Mercruiser 170/470/488 and other 4 cylinder 3.7L Engines 1980 thru 1989.
  • There are other applications on 3.0L 140hp 4 cylinder engines 1990 thru 1995. 
• This part replaces Part 90740. 
  • 90740 has two lengths, but both the longer and shorter versions were superceded by the 99356A1 as the power steering unit that generates the heat is the same for all. 

 Some details to note:   

• You are reading the ad for 99356A1 which has 1" seawater connections. 

• Part Number 99356A2 is the same as 99356A1 but 99356A2 has 1.25 inch seawater fittings.  If you need to order the 99365A1 please go here:  https://www.mrcool.us/99356a1-mercruiser-power-steering-cooler.html 

• You'll see this advertised by competitors with a full bundle which will cool but will also reduce your fluid velocity for the entire cooling system, which reduces it's overall efficiency.  For over 35 years the both Volvo and Mercruiser have opted for a sleeve bundle (see picture with an end view) to reduce the back pressure and loss of fluid velocity to the rest of the cooling system.  This is the right part for you. 

Our product is a drop in replacement for these part numbers:

• Mercruiser 
  • 99356A1
  • 90740
    • note that the 99356A1 superceded the 90740 for the short and longer lengths. 

This part fits the following engines (possibly more):

• from 1980 thru 1989 in most applications. 
• This part went on virtually every Mercruiser engine that had power steering for 10 years and then switched to the 99356A2 for about another 10 years until about 2004 or so.   The the configuration switched to something that looks like the current configuration from mercruiser. 
• If you have another power steering cooler configuration please click here to see the other Mercruiser power steering replacement coolers that we offer.