Thermostat Gasket Confusion

[valkyr]

I need to know which Thermostat Gasket I need.

According to mercruiserparts.com, I need part # 27-41812 which looks like picture #1 below. But the gasket that actually came off the engine looks like gasket #2 below (part # 27-48818). I think I need the 2nd one because its what came off. My engine specs and serial # is listed in my signature below.

 

[flabum]

Re: Thermostat Gasket Confusion

No real differemce.... don't sweat it.

 

[starsnstripers]

Re: Thermostat Gasket Confusion

there's a certain difference there. i would use the same one if the gasket didnt fail and your changing it for preventive maint. or the thrmostat failed. But i'd also look at the outline of where the gasket sits and see which one matches it the best. Maybe both work or they were changed at some point, but thats my 2cents worth. if it didnt leak or fail dont fix what isn't broke. good luck.

 

[flabum]

Re: Thermostat Gasket Confusion

The gasket on the left is the correct gasket IF there are 4 hoses going to the manifolds and riser. IF the thermostat housing had been modified or replaced and there are only two hoses going to the manifolds and none to the risers, then the gasket on the right HAS to be used. If there are four hoses leading to the manifolds and risers, then either gasket will work, but the one on the left is the correct gasket.

Personally, if it is all stock, I'd use the gasket on the left.

 

[starsnstripers]

Re: Thermostat Gasket Confusion

Well Val I see there's a difference after all, Hmm? must be aneurysm huh? lol Always get a second opinion on here. "perfect example here" People dont want to put an effort into an explination why reply? Geesh Anyway Val i'd say the one you took off probably goes to your cooling setup,unless the gasket failed then i'd ? it. good luck maybe someone more knoledgeable will respond hang in there.

 

[starsnstripers]

Re: Thermostat Gasket Confusion

oops "knowledgable"

 

[flabum]

Re: Thermostat Gasket Confusion

Well Val I see there's a difference after all, Hmm? must be aneurysm huh? lol Always get a second opinion on here. "perfect example here" People dont want to put an effort into an explination why reply? Geesh Anyway Val i'd say the one you took off probably goes to your cooling setup,unless the gasket failed then i'd ? it. good luck maybe someone more knoledgeable will respond hang in there.

My first response was a quick, correct one. I had already looked up hi motor in MIDAS and saw his setup (assuming no changes had been made). Both gaskets will work for him with his rig, but the left one is the one that Merc calls for.

 

[valkyr]

Re: Thermostat Gasket Confusion

When you say "left one", I assume you mean picture 1 (attached). But picture #2 is what was on the engine. I'm just doing some maintenance and I don't believe the thermostat has ever been replaced, so I thought it would be a good time to replace it.

I've also attached a pic of my thermostat design...I have the "old design" according to MercruiserParts.com.

"http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=%2019013&ivar=images/CRUISER/19013/27.png&inbr=959&bnbr=150&bdesc=THERMOSTAT+HOUSING+%28OLD+DESIGN%29"]Mercruiser Thermostat Link[/URL]

 

[Don S]

Re: Thermostat Gasket Confusion

Either will work, but the 27-41812 is what the parts manual calls for.
Have you had the boat since new in 88? If not perhaps a previous owner replaced the stat with the wrong gasket.
What is wrong with using the correct one?

 

[valkyr]

Re: Thermostat Gasket Confusion

Nope, only owned it about a year, so perhaps someone replaced the thermostat. I just wanted to get some validation that it was the right gasket before I purchased it.

Thanks everyone!

 

[achris]

Re: Thermostat Gasket Confusion

If the 2 hoses that run to the exhaust manifolds come from the thermostat cover then the right part number is 27-41812. If the hoses that run to the manifold come from the thermostat housing body then the right number is 27-33179-2. Part 27-48818 doesn't show up anywhere on your engine. I checked using your serial number, not the year of the boat.

Chris..........

 

[valkyr]

Re: Thermostat Gasket Confusion

Raw/sea water cooled

 

[achris]

Re: Thermostat Gasket Confusion

Hoses to the manifolds from the cover or the body of the thermostat housing?

 

[valkyr]

Re: Thermostat Gasket Confusion

oh sorry...cover

 

[achris]

Re: Thermostat Gasket Confusion

oh sorry...cover

Then the right part number is as Don said, 27-41812. The gasket that was in there will have done the same job....

Chris......

P.S. You have the 'old design' thermostat housing.....

 

[valkyr]

Re: Thermostat Gasket Confusion

one of the thing that bothers me, is this:

27-41812 - says fits "FITS MCM/MIE GM V-6 & V-8 ENGINES"

27-48818 - says fits "Fits MCM/MIE GM V-8 Engines"

27-41812 seems more like a generic gasket....

 

[achris]

Re: Thermostat Gasket Confusion

From what I could see in the parts manual 27-48818 is for the older V8s, pre-1987.

"FITS MCM/MIE GM V-6 & V-8 ENGINES"

Where are you reading this? Merc parts usually only have the part number on them.

Cheers,

Chris...........

 

[valkyr]

Re: Thermostat Gasket Confusion

P.S. You have the 'old design' thermostat housing.....

I knew that See my second post in this thread

Where are you reading this? Merc parts usually only have the part number on them.

"http://www.psepmarineparts.biz/store/mercruiser_thermostat_housing_gaskets.htm"]Here[/URL]
"http://www.iboats.com/Sierra_18_2844_Thermostat_Gasket/dm/keywords.mercruiser%20thermostat%20gasket--*******.088673755--**********.320219655--view_id.173198"]Here For V8 Gasket[/URL]
"http://www.iboats.com/Sierra_18_2554_Thermostat_Gasket/dm/keywords.mercruiser%20thermostat%20gasket--*******.088673755--**********.320219655--view_id.173170"]Here for where it says V6 and V8[/URL]

 

[achris]

Re: Thermostat Gasket Confusion

Sorry about missing the 'old design' mention...

I see what you're looking at (parts listing). I'm looking at Merc's own parts catalog... I plug in your serial number and it gives me a list of the parts used on your engine, not a list from GLM or Sierra (as the list you have posted are).

Cheers,

Chris..........
P.S. Use 27-41812. I know it's more expensive, but it is the right part according to Mercury.

 

[Don S]

Re: Thermostat Gasket Confusion

I used the same method to find the correct part as Chris (and flabum) did. Instead of using other sites to look up parts, go directly to mercurypartsexpress.com and look up your part numbers directly from merc. They will be supperceded if necessary. Then you can buy the correct part from wherever you want.