how to check real temp.

[cooter9]

On my 49 Standard 8 how can I check to see what the actual real temp. is when up to operating temp. I want to see if my temp. gauge is really accurate or off a little or whatever. Is there any kind of device to check the actual water temp. or the actual temp. in the radiator. That was too many uses of the word actual, sorry.

[Guest JT]

Thermometer. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

[cooter9]

Seriously, I have never done this. Just take off radiator cap evern when hot and stick it down in there?

[WCraigH]

Do NOT remove the rad cap when hot!!!

Besides spewing hot coolant all over you, the engine and all the front body parts, it will NOT give an accurate reading. I don't know what pressure rad cap is used on a 49 (maybe 6psi?), but whatever it is, reducing the pressure to atmospheric changes the boiling point and probably the temp if over 212F at sea level.

The best way is to purchase an aftermarket mechanical temp gauge and install the sender some convenient location in the cooling system. I don't know enough about the straight 8 to make a specific recommendation on location.

[Guest imported_Speedster]

I had a boat with 500ci Caddy engine and I got to thinking it may not be getting to the best operating temp since it had cold lake water going thru engine. So, I made a special freeze plug that went in side of engine block, by using a removable type plug and drilling a small hole in it and epoxying a thermocouple wire into hole. That way I could monitor the water temp at block. Even tho the water also went thru the exhaust manifolds I found that I needed to restrict water flow at outlet valve to get temp up to 180deg, since the cold water was being pumped in by Jet-pump.

I was thinking that someone could use another radiator cap, drill a hole in it and epoxy in a temp gauge wire to temporarily or permanently monitor temp.

[Guest Snopack]

Cooter9:

Your car came out of the factory with a 150 degree thermostat or the optional 160 degree and a 7 lb cap.

You can get a fairly accurate temp. reading with a candy thermometer in the top of the radiator, remove cap cold run the engine until hot and stick the thermometer in the fill neck.

Or if you know someone with a infared temp. gun you can aim it at the the thermostat housing and get a reading.

Keep in mind that the thermostat is on the front of the engine and the temp. sender on the back and depending on the condition of the water jacket and the water distribution tube there can be difference between the front and back, the infared works best as you can read the temp. at varios parts of the engine as an indication of the internal water flow. The price of infared temp. guns has come down and an adaquite one is about $50.

John

[Guest CaptainBristol]

I agree that an infrared temperature gun is a great asset in determining engine temperature. I have used one to look for hot spots on my 288 straight eight, and it made the job easy. I was able to rent a gun at a tool rental place, and you may be able to do so, too. Cost to me was $15 for 24 hours, which was all the time I needed.

You can get an idea of how many of these guns are available by looking here:

http://www.professionalequipment.com/xq/ASP/Infrared-Thermometer/id.22/subID.177/qx/default.htm

All the best,

Mark in Alaska

[Guest imported_Speedster]

I tryed my Idea of the radiator cap with thermocoupe wire installed and it worked Great! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> I had an extra cap that fit my truck so I drilled a #40 hole and sealed it first with RTV and then with epoxy over the RTV. That way it will be easier to remove the wire when I need it for something else. I drove it to hardware store with modified cap installed, then when I got back I plugged it into my digital thermometer and found that my dash mount gauge is very accurate. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> That also tells me that the temp at top of radiator is very close to temp in head where the dash gauge sender is installed.

[cooter9]

I got my laser thermometer gun today and will post the results I get. What temp. is too hot for my 49 with a 288?