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Engine Model Beg. S/N End. S/N Housing Mallory Thermostat Housing
185 (229 CID) 6330183 6919655 18-1994 9-42502
[out of stock]
185 (262 CID) (3) A331455 B527954 18-1994 9-42502
[out of stock]
200 GM 6218462 B525981 18-1994 9-42502
[out of stock]
200/5.0L GM B525982 UP 18-1994 9-42502
[out of stock]
200/5.0L GM B525982 UP 18-1994 9-42502
[out of stock]
205 (262 CID) A331455 B527954 18-1994 9-42502
[out of stock]
205/4.3L, 4.3LX (262 CID) B527955 D714369 18-1994 9-42502
[out of stock]
228 GM 4765100 6218461 18-3651 9-43152
228 GM 6218462 B525981 18-1994 9-42502
[out of stock]
230 GM 6218462 B525981 18-1994 9-42502
[out of stock]
230/5.0L-LX GM B525982 F600999 18-1994 9-42502
[out of stock]
230/5.0L-LX GM B525982 F600999 18-1994 9-42502
[out of stock]
250 GM 4768000 4908849 18-1993  
255 GM 4175500 4767999 18-1993  
260 GM 6218462 B525981 18-1994  
260/5.7L GM B525982 F600999 18-1994  
350 Mag B525982 F600999 18-1994  
5.7 GM (SKI) A338553 B514626 18-1994  
280 GM TRS 4176250 4770199 18-1993  
300 MR/TRS GM 6668677 B430367 18-1994  
500(Gen V) F213293 F615766 18-1994 9-42502
[out of stock]
Engine Model Beg. S/N End. S/N Housing Mallory Thermostat Housing
Notes:
(3) : Old Design

$13.99 - Sierra 18-3568 Thermostat Kit
Compare at $15.49
Part # 18-3568
$15.99 - Sierra 18-3644 Thermostat Kit
Compare at $17.69
Part # 18-3644
$15.99 - Sierra 18-3646 Thermostat Kit
Compare at $17.99
Part # 18-3646
$23.99 - Sierra 18-3647 Thermostat Kit
Compare at $27.49
Part # 18-3647
$13.99 - Sierra 18-3648 Thermostat Kit
Compare at $16.49
Part # 18-3648
$15.99 - Sierra 18-3650 Thermostat Kit
Compare at $18.49
Part # 18-3650
$14.99 - Sierra 18-3651 Thermostat Kit
Compare at $17.49
Part # 18-3651
$15.99 - Sierra 18-3652 Thermostat Kit
Compare at $17.99
Part # 18-3652
$15.99 - Sierra 18-3667 Thermostat Kit
Compare at $18.49
Part # 18-3667
$15.99 - Sierra 18-3668 Thermostat Kit
Compare at $17.99
Part # 18-3668
$21.99 - Mallory Thermostat Kit 9-43157
Compare at $25.43
Part # 9-43157
$15.99 - Mallory Thermostat Kit (140) 9-43153
Compare at $18.49
Part # 9-43153
$17.99 - Mallory Thermostat Kit 9-43152
Compare at $20.20
Part # 9-43152
$15.99 - Mallory Thermostat Kit 9-43151
Compare at $17.50
Part # 9-43151
$14.99 - Mallory Thermostat Kit 9-43150
Compare at $18.25
Part # 9-43150
$13.99 - Mallory Thermostat Kit 9-43100
Compare at $18.70
Part # 9-43100
$14.99 - Mallory Thermostat Kit (140) 9-43020
Compare at $17.38
Part # 9-43020
Sierra
Mercruiser Thermostat Kits 18-3568 Thermostat Kit
Sierra 18-3568 Thermostat Kit
Replaces OEM part #
  • MERCURY MARINE 99155T1
Fits:
  • Model 5.7MIE, Year 1998-2001, Serial# OL002003 & Up
  • Model MX6.2LMPI, Year 2000-2001, Serial# OL680003 & Up
  • Model 454 Horizon MIE, Year 1998-2001, Serial# OL002200 & Up
  • Model 502 Mag. MPI, Year 1998-2001, Serial# OL017000 & Up

Mercruiser Thermostat Kits 18-3644 Thermostat Kit
Sierra 18-3644 Thermostat Kit
Contains:
  • (1) 18-3649 Thermostat 160 Degree - replaces O.E.# 807252T2
  • (1) 18-2553 Thermostat Cover Gasket - replaces O.E.# 27-47510
  • (1) 18-2917 Thermostat Cover Gasket - replaces O.E.# 27-53045-1

Mercruiser Thermostat Kits 18-3646 Thermostat Kit
Sierra 18-3646 Thermostat Kit
Replaces OEM part #
  • MERCURY MARINE 807252Q3
Contains:
  • (1) 18-3551 Thermostat - replaces O.E.# 59137
  • (1) 18-2917 Thermostat Housing Gasket - replaces O.E.# 27-53045-1, 27-33918
  • (1) 18-2844 Thermostat Cover Gasket - replaces O.E.# 27-48818-1
  • (1) 18-2553 Thermostat Cover Gasket - replaces O.E.# 27-47510
  • (1) 18-2834 Thermostat Cover Gasket - replaces O.E.# 27-60208

Mercruiser Thermostat Kits 18-3647 Thermostat Kit
Sierra 18-3647 Thermostat Kit
Replaces OEM part #
  • MERCURY MARINE 807252Q5
Contains:
  • (1) 18-3649 Thermostat - replaces O.E.# 807252-2
  • (1) 18-2844 Thermostat Cover Gasket - replaces O.E.# 27-48818-1
  • (1) 18-2552 Thermostat Cover Gasket - replaces O.E.# 27-33179-2
  • (1) 18-2553 Thermostat Cover Gasket - replaces O.E.# 27-47510
  • (1) 18-7173 O-Ring - replaces O.E.# 25-30224
  • (1) 18-2917 Thermostat Housing Gasket - replaces O.E.# 27-53045-1, 27-33918

Mercruiser Thermostat Kits 18-3648 Thermostat Kit
Sierra 18-3648 Thermostat Kit
160 Degree

Mercruiser Thermostat Kits 18-3650 Thermostat Kit
Sierra 18-3650 Thermostat Kit
Contains:
  • (1) 18-2831 Gasket - replaces O.E.# 27-47590-1
  • (1) 18-3550 Thermostat - replaces O.E.# 59078

Mercruiser Thermostat Kits 18-3651 Thermostat Kit
Sierra 18-3651 Thermostat Kit
Contains:
  • (1) 18-2554 Thermostat Cover Gasket - replaces O.E.# 27-90556
  • (1) 18-2553 Thermostat Cover Gasket - replaces O.E.# 27-47510
  • (1) 18-2834 Thermostat Cover Gasket - replaces O.E.# 27-60208
  • (1) 18-2844 Thermostat Cover Gasket - replaces O.E.# 27-48818-1
  • (1) 18-3551 Thermostat - replaces O.E.# 59137

Mercruiser Thermostat Kits 18-3652 Thermostat Kit
Sierra 18-3652 Thermostat Kit
Contains:
  • (1) 18-2555 Thermostat Cover Gasket - replaces O.E.# 27-89656-1
  • (1) 18-2843 Thermostat Cover Gasket - replaces O.E.# 27-74830
  • (1) 18-3552 Thermostat - replaces O.E.# 76270

Mercruiser Thermostat Kits 18-3667 Thermostat Kit
Sierra 18-3667 Thermostat Kit
Contains
  • (1) 18-2555 Thermostat Cover Gasket - replaces O.E.# 27-89656-1
  • (1) 18-3555 Thermostat - replaces O.E.# 99155A1

Mercruiser Thermostat Kits 18-3668 Thermostat Kit
Sierra 18-3668 Thermostat Kit
Contains:
  • (1) 18-2552 Thermostat Cover Gasket - replaces O.E.# 27-33179-2
  • (1) 18-2553 Thermostat Cover Gasket - replaces O.E.# 27-47510
  • (1) 18-2554 Thermostat Cover Gasket - replaces O.E.# 27-41812
  • (1) 18-3551 Thermostat - replaces O.E.# 59137
  • (1) 18-7173 O-Ring - replaces O.E.# 25-30224

mercruiser thermostat kits-mallory thermostat kit 9-43157
Mallory Thermostat Kit 9-43157
Replaces GLM #:13101
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Replaces Original Equipment Manufacturer # (OEM #):807252Q5
Fits Application:1987 & newer GM engines w/160 t-stat & standard cooling

mercruiser thermostat kits-mallory thermostat kit (140) 9-43153
Mallory Thermostat Kit (140) 9-43153
Replaces GLM #:13370
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Replaces Original Equipment Manufacturer # (OEM #):27-47590 1+ 59078
Fits Application:Gm inline 4 & 6 cyl.

mercruiser thermostat-mallory thermostat kit 9-43152
Mallory Thermostat Kit 9-43152
Replaces GLM #:13380
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Replaces Original Equipment Manufacturer # (OEM #):27-90556+27-47510+27-60208+27-48818-1+59137
Fits Application:3.7L 4 cyl.

mercruiser thermostat kits-mallory thermostat kit 9-43151
Mallory Thermostat Kit 9-43151
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Replaces Original Equipment Manufacturer # (OEM #):807252Q3
Fits Application:1982&older Ford/GM eng. w/std cooling/1996&older hi-perf. w/clsd cooling

mercruiser thermostat kits-mallory thermostat kit 9-43150
Mallory Thermostat Kit 9-43150
Replaces GLM #:13390
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Fits Application:Many w/old design housing and 142* t-stat

mercruiser thermostat kits-mallory thermostat kit 9-43100
Mallory Thermostat Kit 9-43100
Replaces Original Equipment Manufacturer(OEM):Mercruiser
Replaces Original Equipment Manufacturer # (OEM #):N/A
Fits Application:18-2917, 18-2553, 18-3649

mercruiser thermostat kits-mallory thermostat kit (140) 9-43020
Mallory Thermostat Kit (140) 9-43020
Replaces Original Equipment Manufacturer(OEM):MERCRUISER
Replaces Original Equipment Manufacturer # (OEM #):27-47590 1+59078


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Our standard shipping method is UPS ground, which typically takes 2-5 additional transit days after the order has left our warehouse, depending on your delivery address. We also offer other shipping options, including expedited delivery, and the actual delivery date will depend on the shipping options you choose.

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Most products sold by iboats.com can be purchased and shipped to Canada. Some restrictions apply to certain items, such as hazardous materials, over-weight products, and the method of shipping. Available product lines, shipping rates and fees may vary depending on the delivery address for your order.

Currently, iboats.com offers ground shipping to all Canada provinces. Our Canadian brokerage service accelerates your orders through the Customs clearance process and facilitates the delivery of your order through Canada Post or the best method based on your shipping address. We do not currently offer expedited shipping methods to Canada.

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  • If the merchandise you received was defective, damaged, or an error was made by iboats.com, simply return the merchandise within 30 days of the original shipping date for a full refund.
  • See the specific requirements and instructions below for United States or Canadian orders.

Returns for U.S. Customers

We want to make it as easy as possible for you to return an unwanted item; after all, we want you to return again and again as a satisfied iboats.com customer, and to also continue recommending us to your friends.

As mentioned above, if the merchandise you received was defective, damaged, or an error was made by iboats.com, simply return the merchandise within 30 days of the original shipping date for a full refund. Merchandise must still be in brand-new, unused condition with all original packaging in good condition; plus parts, accessories, manuals, and/or warranty cards included. Please note that all return merchandise must be accompanied by an RA (Return Authorization) number issued by iboats.com. To receive your RA number simply call our Returns Department toll-free at 1-800-914-1123 or email us at returns@iboats.com.

If for some reason you need to return merchandise for reasons other than those mentioned above, follow the same procedures, obtaining an RA number from iboats.com, within 30 days of the original shipping date. Please note that there may be restocking fees, shipping costs, or product change order costs associated with some returns. Feel free to check with the iboats.com Returns Department for specific terms, conditions, and eligibility.

Returns for Canadian Customers

We request that all Canadian customers verify and re-check that the products you are ordering are what you want and are correct for your application or intended use. iboats.com does not accept any return merchandise on Canadian orders, unless the merchandise you received was defective, damaged, or an error was made by iboats.com. In such cases, return the merchandise within 30 days of the original shipping date for a full refund, following the procedures below.

Canadian orders involve many additional costs dealing with Customs, Provincial taxes, brokerage fees, and more, making product returns complicated and very expensive and costly for both the customer and iboats.com. Again, help us serve you best by verifying that the products you are ordering are what you want so we don't have any costly returns or have to deny a return.

If a return meets the criteria mentioned above, merchandise must still be in brand-new, unused condition with all original packaging in good condition; all parts, accessories, manuals, and/or warranty cards included. Please note that all return merchandise must be accompanied by an RA (Return Authorization) number issued by iboats.com. To receive your RA number call our Customer Service Department toll-free at 1-800-914-1123, Tuesday-Friday, 10am-7pm EST, or email us at returns@iboats.com. We will provide further details on where and how to mail the merchandise. Please note that returns sent from rural Canadian addresses may take up to five weeks to process after the package is mailed.

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