Temp guage (again) Now what???????

Well if you followed my previous thread:
http://www.jalopyjournal.com/forum/showthread.php?t=424663

you know my electric guage was kicken my ***. Well I was 99.99% sure the guage was bad so I went with a mechanical guage. Now, with my first guage when I started it and it warmed up, the guage slowley rose to just under 150 and then dropped. I have a 145 t-stat so this all makes sense. My sending unit was in a block that mounts to the engine block and it was below the t-stat. The engine is a 250 straight six.
When I switched to the mecanical guage the sensing probe was to long to go there so I had to put it in the side of the head. This time when I started it the temp rose to almost 190 before the t-stat opened and the temp dropped. and then it only dropped to about 170.
I'm thinking it could be one of two things: I could have some air in the cooling system since I had to drian it down to change **** around. Or, I could be just getting a unusually high reading with the probe in the side of the head.
Any ideas? Thanks, Todd

 

I think you will get a higher reading in the head. While the temps don't sound bad, 45 degree's over the t-stat opening temp seems strange.

 

Running at 170 degrees is even considered low...Sounds like everything is fine, to me. It will be warmer from the head, to answer your question. Enjoy!

 

Those laser type heat readers are pretty nice for sorting this stuff out some.

 

Not traditional.

Damn now I need something I didn't need just a few minutes ago.

 

With the above responses in mind, I have a question. Do you have any sort of byp*** that allows the water to circulate when the Tstat is closed?

 

I don't believe there is any kind of byp***. Todd

 

When I switched to the mecanical guage the sensing probe was to long to go there so I had to put it in the side of the head.

go to the junk yard and pick up a 80's something gm 350 thermostate housing with the dual sensor inputs on it ...i got one out of a 80's elcamino i think it might have even been a 305 ..remove one of the old sensors and install from your guage kit the fittings and than install the temp probe it should give you a accurate reading at the thermostate..i have done this on my mustang and my 56 chevy and never have a problem ..if you cant figure this out pm me and ill post a picture of what im talking about ...

 

The closer to the thermostat you can get the sensor the more accurate the reading will be. You want to know the water temp as it leaves the engine going to the radiator.

Frank

 

That makes sense. I guess I could make up some sort of bushing so the probe doesn't go in as far. It only had like a 1/16" to go before it hit the t-stat. Todd

 

Your engine will run more efficiently at 170 or 180 or 190 than at 145.

 

i never heard of a 145 deg t-stat thats way too low 190 sound right or a 195 still, his temp is ok, you'll get different temps in different places

 

The reason you need at least 180 is to get rid of the moisture in the engine oil. Anything below that is not gona be hot enough to COOK the water out of the airand oil and you end up with condensation, and white stuff on cooler parts and rust. The other reason is for the heater to work if needed. Iceman

 

this is what i used and it works perfect..i used a 180 theremostat and have no problems ..

 

Lorodz thanks for the pics. Todd

 

ya welcome hope this works out for you ,,,