2001 Deville 04 CTS Has me confused!

[cadman90]

I have two caddy's a 2001 Deville with 243,860 miles and a 2004 CTS with 185,211 miles, never had any major issues with any of them. Untill last week the nozzel where the radiator hose goes developed a crack so I had my neighbor (who was a former mechanic) install two new radiators I purchased. I did this on the deville even though the leak was minimal to save from a major repair resulting in this small crack and on the cts as a precaution. Now before hand this Deville and CTS had NO engine or overheating problem! the have taken us all over the country with out one complaint! Now two days ago comming back from a town 78 miles away ascending a long hill the darn thing overheated "engine hot/ac off" idle car" engine overheated" Because there is no cell coverage way out here on that highway we leap frogged home. The other sad part of this is I had the CTS radiator replaced as a preventative preccaution at the same time. I tried that same long hill with the CTS and WOW it started to overheat aswell,lucky I had my son with his tow dolly, so rather then risk damage I towed it home. We do have a newer ford fusion we are driving around just f.y.i. Now here is where I need help... WHY did they both start over heating after a radiator change, was work on these older caddy's cooling system just a cataylist for that problem? And why are there horrible gurgleing noises comming from both caddy's when started in the morning? I might point out that both cars exhibit no overheating or other issues while being driving around town even with the a/c on high, the heat does not get hot and only when we get on the highway and put them underload does the temp start climbing . There are no leaks of any kind,even though one says coolant level low it does not use it, oil is good,cooling system liquid is good,no smoke or steam out tail pipes no wierd noises except the gurgling noise from behind the dashes. I asked my neighbor what he may think about it and his response was he changed them refilled cooling should be good" Someone give me some advice before I throw a lot of cash into these two faithful companions of ours. R.I.P. Deville and CTS?

[waterzap]

I might be very wrong, but I did read somewhere, if you replace the radiators, make sure the insulation around the side of the radiators are installed properly as well.

Also, there is a small hole in the bolt that connects to one of the smaller bypass hoses on the right (if looking from front) side of engine. Make sure that hole is open, it can get clogged easily, and then the system won’t get the air out. Your neighbor probably does not know about the bolt, but it’s a well known problem. Just clean it out.

The horrible gurgling noises might be air in the system.

There are many posts about the air bleed system that gets clogged. Problems usually arise when you change the coolant and let air in. In your case, a new radiator would also do it.

[Göran W]

Yes! The "gurgeling" is definitly air!!!

[Cadillac Jim]

One thing that can cause what you are seeing is having less than 50-50 antifreeze in the radiator when you're done, or having a leaking or faulty radiator cap. Yes, it's spring, not winter, but antifreeze raises the boiling point of the water, as does pressure. Without 15 psi and 50-50 antifreeze, you will have steam pockets in the head when you stress the engine that will tend to collect around the thermostat. The bypass hose lets out a certain amount of these so if it gets clogged you will have the same overheating problem even with 50-50 antifreeze and a good radiator cap.