thermostat was missing

[jcdsog]

just did a tear down and my thermostat was not in there. is it a big deal? do i need to put one in or will it be ok without it?

thanks.

 

[tashasdaddy]

Re: thermostat was missing

yes, you need one. the engine will not run, at the proper temperture with out it. can cause fouling of plugs, poor performance, and other problems.

 

[red_chaser]

Re: thermostat was missing

what about the pressure relief valves next to the thermostat? how often do you change out those and how do you tell when they go bad?

 

[emdsapmgr]

Re: thermostat was missing

The pressure relief valves are made of nylon and can last for many, many years. If the impeller ever goes bad, resulting in a powerhead overheat, these nylon parts can deform due to excess heat. Then they should be replaced. You might want to have a look at the rubber seats around these nylon valves, however. If they look old, cracked, you should probably should replace them.

 

[Texasmark]

Re: thermostat was missing

You need to see just how far up the block the thermostat hole is located. On my Merc 3 cyl and on V6 engines, the stat is not at the top of the block so at lower speeds where water volume from the pump is not high, you can have a problem keeping the entire block filled with water which certainly isn't good for the top cylinder......in addition to all the other reasons to have it.

Mark

 

[tashasdaddy]

Re: thermostat was missing

mark what do mercs have to do with a johnson forum? your reasoning, is why J/E moved their tale tell connection high up on the block. so that the block fills with water. tale tell is the last place water goes.

 

[jcdsog]

Re: thermostat was missing

thanks for the input. im not sure what pressure release valve you are reffering to tho. are you talking about the plastic shroud that holds the thermostat in? it was a little warped by the holes but as i was taking the old gasket off with a razor i shaved off the high spots. it wasnt much.

 

[Texasmark]

Re: thermostat was missing

mark what do mercs have to do with a johnson forum? your reasoning, is why J/E moved their tale tell connection high up on the block. so that the block fills with water. tale tell is the last place water goes.

I don't know man. My comment was based upon the fact that regardless of all other things considered, if your block can't completely fill with water because you have decided to remove your stat, then your upper cylinders will suffer....unless your stat is in the very top of the block, like horizontal, not vertical. That's it; no more, no less. But I gave up on OMC back in the late '70's so what do I know??????????????, you're the Xpert.

Mark

 

[emdsapmgr]

Re: thermostat was missing

jcdsog, my response on the pressure relief valve was related to the question asked by red_chaser. Not all engines have the pressure relief valves. What engine model/hp are you working on?

 

[kenmyfam]

Re: thermostat was missing

Yes you need a functioning thermostat.
I will elaborate no further as to reasons.
My 2 cents.