Engine Temp question?

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Mar 2, 2011 | 07:14 PM

trainor

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From: Bishop CA

Engine Temp question?

Changed thermostat in my 75 350 today. Went with a 180 deg. just like what I took out. Now the engine is running about one needle width above 200 deg. Before it was running about 2 needle widths below 200. Is this good enough or should I change it out. I'm going to be hooking up the AC in a month or so and I wanted to get the engine running cool for that. Any Suggestions or am I OK where its at? Correct me if I'm wrong but doesn't the thermostat have nothing to do with the engine run temp, does it only have to do with when the water is released? Thanks guys.

Mar 2, 2011 | 07:25 PM

7T1vette

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From: Crossville TN

Sounds like you have an air pocket in the coolant. You need to 'burp' the system to get trapped air out of it. Then it will flow properly and cool as it should. Your temp should not be over 200F with a 180F stat.

Mar 2, 2011 | 07:29 PM

trainor

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From: Bishop CA

Quote:

Originally Posted by 7T1vette

Iv'e got several kids and knew how to burp them, but how do I burp the system.

Mar 2, 2011 | 07:31 PM

Chromie69

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From: York Pa.

Yup sounds like a pocket in there..make sure you have heat..that's funny..I got kids too and they burp on their own now! Turn the heat on and make sure coolant is flowing thru the heater core..feel the hoses going to it ..if they are cold or only one is hot that's where the pocket is..if you have a driveway that is up hill you can point the front of the car uphill and run the car..make sure you leave the rad cap off..don't fill the rad all the way..leave it about 6 inches down as it will rise when the air pops out..or jack the front end up in the garage safely and burp it out..

Last edited by Chromie69; Mar 2, 2011 at 07:36 PM.

Mar 2, 2011 | 07:32 PM

trainor

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From: Bishop CA

Quote:

Originally Posted by Chromie69

Yup sounds like a pocket in there..make sure you have heat..

How do I burp the system?

Mar 3, 2011 | 07:31 PM

caribbee

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From: Coolidge, Antigua , West Indies

First make sure the engine is cold and u have fluid in the rad reservoir. Remove the rad cap and leave it off. Start the engine and let it idle to operating temp. Watch the fluid in the rad, as the engine heats up the fluid might come out of the rad, dont mind this, let it do its thing. Continue to watch the fluid level in the rad, u will know when the thermostat opens when the rad fluid starts to go down and the temp needle gets to the thermostat temp. Let it flow for a bit and add fluid to the rad as its flowing. Once its full put the rad cap back on. That should do it.

Mar 4, 2011 | 09:40 AM

gcusmano74

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engine temp

Think about it. The temperature gauge in a '75 car is now some 35 years old. It may no longer be accurate.
Get an infrared thermometer from somebody like Harbor Freight and check the temperature of the top of the thermostat housing when the engine is fully warm. The temp should be somewhere between 180 and 200 degrees F.

Mar 4, 2011 | 09:51 AM

noonie

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From: Florida

I always measure the tstat housing and the radiator upper inlet and then the pass side rad tank as low as I can and the water pump at the inlet.
You should be getting anywhere from 20 to 30° difference there if the radiator is up to snuff. If it is then your inlet temp should be very close to the tstat rating.

Keep the reservoir tank (plastic on fender) full for a few heat/cold cycles (driving) and the level should eventually drop and the air expelled from the engine.