1994 eldorado overheating/ coolant leak, badly need expertise.

[Jaymefromseattle]

Hello, I greatly appreciate any input on the issue. I recently purchased an 1994 Eldorado with only 72,000 miles, I obtained it threw my mothers BF Grandma, yes, very akward...but one he'll of a deal. Interior and exterior immaculate. The first week of owning the car I never drove it hard only locally though I could feel that it had a strong punch to it, 4.6 l. Then I started driving on the freeway and such..the car would gradually over heat at higher rpms or thrust, going up long hills, etc. The dashboard electronics would tell me it's overheating, otherwise no other indications. Either the car would say 'shut off' or it would go in limp mode. Or both. After the first time in limp mode I realized this couldn't be healthy so I pulled over and noticed coolant leaking only after the coolant temp was above 150, a buddy said it appeared to only exit the overflow..this happened a few more times with me constantly putting dex into it.

I took the car into the shop and they did an engine compression test and it came back fine. But he said they pressurized the radiator and it has a slight leak..I've never observed this, the only leak I have seen is passengers side. So tommarow we are replacing the radiator and cap, hopefully flushing the system and changing the thermostat , I checked the computer and the only codes came back is too hot fluid. I'm just a bit skeptical..also two mechanics 'said they could not find one coolant leak, as though I'm crazy" but the 4 or 5 times vie pulled over after overheating I've seen orange antifreeze, also after letting the car sit and putting cold dex in, the overheating seems to stay at bay a little longer. ANY HELP please.

[lothos]

one quick thing to check is the "bolt with a hole". There's a coolant line that runs across the top of the engine and goes to the overflow tank. Coming out of the engine there's a hollow bolt that sometimes gets plugged. Pull the hose off and make sure coolant flows from that line.

[MAC]

It's possible the radiator cap is bad. I had this happen with my '05 STS. Replaced the cap and no more coolant leaking out the overflow tube. A bad cap can be one of those things that you wouldn't look for initially, which is exactly what happened in my situation. I was looking for the leak one day and pulled the overflow hose and saw it dripping coolant. Sometimes I would see a lot of coolant on the pavement and other times very little to nothing. Eventually it became worse and then I finally realized the cap could be bad.

[Jaymefromseattle]

I noticed that when I got my car back yesterday and there was a new radiator but not a new cap, I thought it was sloppy...so we sent it back this morning, but what u described is almost exactly what is playing out..

[Cadillac Jim]

There is more than one kind of radiator cap. The old style was intended for use with a non-pressurized surge tank, where the overflow tube fed the resivoir and coolant was sucked back into the car when the engine cooled. The new style, with a pressurized surge tank as used in Cadillacs for over 20 years now, does not have the same check valve, and seals better. Get the cap either by a catalog for your car, or from the dealer.