I am having an issue with my daily driver with the famous overheating and water disappearing trick. I have verified the below

Water is not leaking anywhere
When coolant is full. Verified that the raditor is flowing
Both fans are cycling as should.
Changed Thermostat

I can feel the radiator and car runs fine for about a week and then the temp hand starts to creep back up. Let the car cool down and add coolant and runs for another week or so fine.

I know what this is leading to (Head Gasket replacement) but wanted to see if anyone else had any ideas before tearing into. Any insight is appreciated.

 

If you suspect a head gasket, I would do a 'leakdown' test on the cylinders and look for air bubbles in the radiator. All that means is you pressurize the cylinders, one at a time, then look in the radiator neck for bubbles. If you see them.....at least you know for sure what's causing it.

I guess you can do a compression test too, but I think the leakdown/bubbles would be proof positive for me.

 

Alright thanks, I will go some research on how to do.

 

you replaced the radiator anytime?

 

No have not replaced the radiator. There are no visible leaks before or after driving the car or after it has set for a long period of time. I can also see the coolant flowing across the coils after the system is up to temp.

Something specfic or experience you had with the radiator causing these symptoms?

 

Head gasket. You can use a combustion leak tester if you want. Ir just observe if there is pressurized gas in the cooling system. Sorry dude.

 

What I was thinking as well, but was trying to lie to myself. Even though this is just a daily driver. I have had this happen a couple of times on force induction applications. I will still go ahead and do a compress test since it is a pretty simple process. Thanks to everyone for their insight.

 

Depending on how much you drive and given it takes a week, there is a chance that you have a hole in the radiator that is so small you can't see the water coming out. It has happened to me before. Also, you can pull the radiator cap and start the car and look for air bubbles shooting up. If you have a small leak in the cooling system only, you will see very slight air bubbles which could be the air getting into the leak in the radiator/hoses/etc and coming through the top of the radiator, however if you rev the engine via the throttle and it gets proportionally worse then it's the head gasket.

 

Any chance the WP is weeping? Try letting it sit with the rad cap off....trust me, I've found some of those mystery leaks by removing the cap and letting it sit.

Or the other choices after the comp test. Trusty cooling system pressure test, UV dye...seen those getting pretty cheap these days.

What part of the TN sticks are you in? Former resident of Hickman and Shelby county...I know, Shebly county is no where near the sticks.

 

Thanks will keep that in mind. I am in the little town of Cleveland. About an hour south of Knox.