Sierra Thermostat and Gasket Kit

[mcoffey]

Figured I would share my new found knowledge on an obscure Sierra thermostat and gasket kit.
So the kit Sierra lists for my 1996 5.7 2bbl A1G2 is the 18-3647 (and the display pack version of 18-3647D). This kit contains the 160 degree thermostat, the correct housing gasket that has the 2 brass rivets near each thread hole as well as the round cork gasket that sits between the thermostat and the housing (and then the white plastic piece then slides in to hold it all together).
It also contains a round rubber o-ring, an incorrect housing gasket that is just too small to fit over the white plastic piece, an incorrect housing gasket that has a cutout for some sort of protrusion and also a gasket that looks to be for some sort of block off plate.

So count them, yep that is right, 4 extra items in this kit that go straight from the box to the trash as I do not need them, have no clue what they are for and clearly do not fit my boat.

All of this for the bargain price of $24.00 (on Amazon anyway).

So a friend of mine just stumbled across a kit that has absolutely no description to it at all.
That would be the 18-3648. If you look it up in the Sierra Catalog, it shows simply as "Thermostat Kit 160".
Hmmm, that is odd. Every other kit lists all of the components that come with it as well as the OE Merc. numbers, why not this one?
He bought it hoping it would work and it only cost $18.76 (on Amazon again).

Now since I had the 3647 and he had the 3648, I decided to compare them. First of all, the 3648 kit only has the thermo, housing gasket and round cork gasket so it does look promising.

I open all of it up and start looking.
Thermostat is identical, same 160 degree, same made in china marking, same exact size. CHECK
Housing gasket is identical, same brass rivets next to bolt holes, same exact size. CHECK
Round cork gasket is identical, same exact size. CHECK

So why am I paying almost $6 more for a kit and then throwing away 4 of the 7 items that come in the box?

NO MORE! I will now be buying the 18-3648 kit as it is the correct kit for my engine and contains only the gaskets I really need.
No more waste or money, no more waste of parts


So for all that do this stuff themselves, check it out and see if those are the gaskets you need. If they are, make the switch and save some cash!

[shrew]

I'd say it's just a matter of what you really need. The more expansive kit looks like it's a more 'Universal' Kit. If 18-3648 works for you, then go ahead an use it.


18-3647 Thermostat Kit: (Contains)

18-3649: 160 Thermostat
........................................
18-2844: Thermostat Gasket
* V8 Thermostat Housing Gasket
* Used on Mercruiser GM V8 engines with log style manifolds * Replaces Mercruiser 27-48818 Exhaust Elbow Mounting Gasket

........................................
18-2552: Thermostat Cover Gasket
Replaces: Mercury #27-33179-2
Fits: 3.0L - 8.2L

........................................
18-2553: Thermostat Cover Gasket (Mercruiser Sterndrive)
........................................
18-7123: O-ring (for OMC/Cobra Sterndrives)
...................
18-2917: Thermostat Gasket

• Replacement for Mercury/Mariner Outboard #27-53045-1, Mercruiser Inboard/Outboard #27-33918
• Sterndrive/Cobra Inboard/Outboard #312797, 3701777 for GM's

=================

18-3648 Thermostat Kit: (Contains)

18-3649: 160 Thermostat
.................................................. ...
18-2553: Thermostat Cover Gasket (Mercruiser Sterndrive)
..................................
18-2917: Thermostat Gasket

• Replacement for Mercury/Mariner Outboard #27-53045-1, Mercruiser Inboard/Outboard #27-33918
• Sterndrive/Cobra Inboard/Outboard #312797, 3701777 for GM's

[mcoffey]

Maybe I am asking for too much then. I did work in the auto parts industry for a number of years so I know how most of this works. Their application catalog should list the correct kit or at least make note of this other kit fitting some models if indeed this kit is needed for some in my range.
Their catalog should also list the items contained in the kit, not just a generic label of 160 kit. I know you found it listed but it is not in the Sierra catalogs that I found, it is not listed on iBoats.com nor is it listed on Amazon.

So to me, I see this as Sierra influencing me to buy the more expensive kit even though I do not need half of what is in there. This is because their catalog lists this kit as the correct (and only kit) that fits my engine.
They then attempt to hide what components make up this other kit so it is not obvious it will fit my application.

Again, maybe I am expecting too much or reading into it too much. Maybe they are just matching an OEM kit and nothing more. I do expect them to at least describe the items included in each kit so I can make an informed decision when buying.
This specific purchase was an impulse buy and a gamble at that. Now that i know it works and contains everything I need, I will use it from now on.

I was hoping this would help someone else in their purchase too if they also use the same kit and throw away the same items as I do. I did not intend this to be a compaint at all so sorry if it came across that way.
Just trying to save a few $ where I can and where it makes sense

[shrew]

To me, part of the problem is you don't match the kit with the engine necessarily. As you know, when you lookup parts, the part doesn't typically list all the applications it will apply to. Rather you lookup the application and it lists the part numbers that correspond. So Sierra might make a generic kit that applies to multiple boats. That part number will be listed in each application, such as a Mercruiser <blah, blah, blah>. If you're looking up Mercruiser, you don't care that it also fits an OMC. Liekwise if you looking up an OMC. You wouldn't want to go through every Sierra Kit number to find the make/model it corresponds too, because that would be incredibly inefficient.

so Sierra happens to point to a generic kit that fits multiple applications. How did you stumble on the alternate part number?