89' Mercruiser circulating pump

[Captain Cobb]

good evening fellow boaters, I have an 89' Regal Medallion 185 with a Merc. 4.3 v6. serial number oc609703.... I just replaced the raw water impeller in the outdrive yesterday, and when i fired the motor up on rabbit ears I discovered water dripping from the weep hole on the engine circulating pump. my question is what Sierra PN do I need to replace this? the 18-3599 or the 18-3583? the pump has GM 10108455 stamed on it. thanks you guys..

 

[Bt Doctur]

18-3599 use with a composite timing chain cover
18-3583 use with metal timing cover
According to that SN you have the metal cover so WP # 18-3583 is used.

 

[Captain Cobb]

18-3599 use with a composite timing chain cover
18-3583 use with metal timing cover
According to that SN you have the metal cover so WP # 18-3583 is used.

Awesome, thank you thank you thank you! ordering now..

 

[Captain Cobb]

while we are on this topic, how about the Sierra PN for the thermostat on this engine? I probably should replace that also..

 

[Bt Doctur]

140 /deg 18-3668 .cover most applications plug your SN in here https://webapps.brunswick.com/literature/literatureSearch.do

 

[Captain Cobb]

140 /deg 18-3668 .cover most applications plug your SN in here https://webapps.brunswick.com/literature/literatureSearch.do

Awesome, thanks for the link!

 

[MikDee]

If you can get the pump without the S.S. back cover, & put yours on you can save a lot of money!

 

[Captain Cobb]

If you can get the pump without the S.S. back cover, & put yours on you can save a lot of money!

That's a good idea. Too late for me, I already ordered one. The thing that surprised me was the huge variation in price. Napa Auto came in the the most expensive at $167, the local Mercruiser shop was $130, the outta town Merc. shop was $150, and Amazon was $83. You can guess which one I bought..