Tstat Housnig Configuration

[akincer]

Mercruiser 4.3 Alpha

S/N OW626893


So when I was winterizing, I noticed some discrepancies between the parts lookup diagrams and my engine. I was hoping you guys could help me clear it up.

Three pics attached.

Standard cooling system and thermostat and housing are directly from the parts catalog. My tstat is a picture (not a great one) of my actual unit when I had it off for winterizing.


Tstat and housing shows only 4 hose connections to the housing. That is clearly wrong. My housing has 6 hose connections. The standard cooling system diagram shows what appears to be the correct housing with 6 connections.


Also, the tstat and housing diagram appears to show a gasket between the housing and the block and seems to show that the thermostat comes out of the bottom of the housing.

As far as I can tell, there is no gasket between the housing and the block and the thermostat does not come out of the bottom. It looks to me like there is a plate on the top of the housing that would be taken off to allow the the tstat to come out of the top.

Can you guys help me with the proper assembly of my tstat housing.

Thanks!

 

[agallant80]

Re: Tstat Housnig Configuration

We have the same setup and I went through the same confusion. The cover on the top is for a check valve that only lets water flow one way. To remove the thermostat from the housing GENTLY pry up on the plastic silver thing around the thermostat. Also don't use the auto parts gasket, you have to use the mercruiser one, it has grounding lugs in it.

 

[agallant80]

Re: Tstat Housnig Configuration

Here is a breakdown image showing the collar holding the thermostat in.

 

[akincer]

Re: Tstat Housnig Configuration

So, let me see if I understand correctly.

I think you are saying that the termostat comes out of the bottom of the housing as descrbed and that in order to get it out I would need to pry on the silver ring that is visible in the picture of my tstat housing. That would mean that the diagram is correct and that the silver ring in my picture is item #7 in diagram. Sound right?

Also, with regard to the gasket, I'm still a bit confused. I think this would be item #10 in the diagram. As you can see from my picture, that gasket is not on the housing. It did not look like it was on the block either. I remember seeing 1 or 2 little metal pins that might be the groudning lugs you mention, but it sure didn't look like there was a gasket. Is it possible that mine was assembled incorrectly and I just got lucky that it didn't leak or is it possible that there was a configuration that did not require a gasket?

Thanks for your help

 

[agallant80]

Re: Tstat Housnig Configuration

So, let me see if I understand correctly.

I think you are saying that the termostat comes out of the bottom of the housing as descrbed and that in order to get it out I would need to pry on the silver ring that is visible in the picture of my tstat housing. That would mean that the diagram is correct and that the silver ring in my picture is item #7 in diagram. Sound right?

Yes that is correct. Remove part #9 gently.

You need a gasket. Perhaps the last guy who took it off did not put another one on or perhaps the dealer/factory messed up but you should have one. It looks like you have remnants of a gasket in your photo. Its a paper gasket.

 

[agallant80]

Re: Tstat Housnig Configuration

Does this help?



It will feel like it is welded in there but be gentel. I used needel nose plyers and a flat head to remove it. Once its free it slides out and in pretty easy. There is a bump on it that will allow it to be installed only one way so you can't mess it up putting it back togeather.

Here is the gasket you need.
http://www.jmsonline.net/710-27-53045-1.htm?gclid=CPD8rs7Fm7oCFQqe4AodhggACg

 

[akincer]

Re: Tstat Housnig Configuration

Thanks to all. Very helpful.

In my previous post, I said part 7 in the diagram, but you correctly pointed out that I meant part 9.

I think will buy the gasket and take it apart one more time. If it's not there, I will add it. If it is, I will replace it. Better to invest a little time now than to have a leak in the spring.

 

[Volphin]

Re: Tstat Housnig Configuration

While you have it out, test the thermostat in a pan of heated water. Ensure it is fully opening and at the right temp.