It may be that your in the never ending cycle of over filling your radiator or you possibly have a faulty radiator cap.

 

CutlassSupremer, I would have your radiator pressure tested to check for possible head gasket failure. Many videos on YouTube. The coolant may not be contacting the sensor at all if it's low on fluid. Happens in race cars when they overheat and loose fluid


Oldssupreme, the thermostat should be a quality high flow unit, every component of your cooling system should be evaluated. there is a great book you can e-download (out of print). Also consider waterless coolant, it doesn't boil below 300 degrees. Good luck.


https://www.amazon.com/Engine-Coolin...ooling+systems

 

Thank you to all who have replied ! My next step is getting a radiator pressure testing unit .......
I believe with all the comments made ... it must be a bad head gasket over-pressurizing the cooling system.
Although there is no white or gray exhaust .... and no water in the oil.
I'm going to bet that there IS pressure in the cooling system BEFORE the engine gets warmed-up. The pressure testing device will confirm.
The CAP is new and it's a Standt brand so I will bet that's not the problem.
I haven't been filling above the "Fill-Level" for a while BUT It still pukes out coolant.
The coolant seems to have way too much air bubbles in it.
With only 1/2 of the Radiator filled .... it doesn't seem to puke much OR it won't overheat (according to my S-W gauge) ..... but this can't be good for the engine or cooling system.
I will report the results of the Pressure Test, soon. Thanks everybody!

 

A mere $174.60 on Amazon, and a number of reviews describe it as a long advertisement for Evans Cooling.

- Eric

 

Sorry, wasn't trying to make a sales pitch. The basic information in the book is very good, and helps in troubleshooting cooling system problems. I picked the book up at a swap meet for $8. As a matter of fact it's the only cooling system book I've read that concentrates on cooling system design.

 

Didn't mean to knock it, I just wanted to add the details, since all you posted was a mention and a link.

It's good to know that it's got good information on cooling systems. I'll keep an eye out for it, but not on Amazon.

- Eric

 

I wanted to say this since it may not have already been said explicitly, but it is antifreeze that causes white exhaust. If you don't have antifreeze, the exhaust won't have white smoke.

I say this because when I was in high school my engine was losing coolant and folks would ask if there was white smoke out the exhaust. I said no, so the reply was always then it's not a head gasket. No one ever asked if I had antifreeze in the system - I did not at the time; I was running plain water. I eventually found that the head gasket was indeed leaking.

 

My 5.9 magnum had the heads cracked in the cooling jackets. The magnum heads always crack, just most of the time the owner doesn't know. With a 7 pound cap, it would just push past the cap and all over everywhere. With a 14 pound cap, into the oil. The head gaskets weren't blown this time. If you are running factory steel head gaskets, I have seen them rot out due to bad coolant but that usually puts coolant in the cylinders and it starts like it is under load due to a cylinder full of coolant.

 

Yes, the typical failure mode is that they rust between two (or more) cylinders.
If you look at a gasket, that's a thin point.

- Eric

 

Agree, that is where mine rotted out.