JimDeville

Hi Guys, Thanks Bruce you're right it's a balanced system, need to check each part. Yes, the cooling fans were out for about an hour, got the new relay & they're ok now. The surge tank has actual cracks in the plastic that are leaking steam, pressure, coolant. Definitely not holding pressure. That's why I was wondering if no pressure alone like leaving the pressure cap off & driving around in hot weather would cause overheating by itself. Thanks JD, yes, coolant leaking from overflow hose & tank. Tank has bad leak at both hose connects, plastic has failed. Going to test the system today for the head gasket leaking, hopefully it's not. The new tank comes next Monday, after that I will put in tank & new cap & pressure test to hold 16LBS is that correct? Just trying to keep her running good til I can get a newer one. Need it to be dependable for wife & kids. Wish I had joined this forum years ago!

Hi Bruce, thanks for the welcome. Haven't pulled codes, but I will and I'll check out the exhaust gases test kit tomorrow. The cooling fan relay was blown, replaced it & fans are fine. Motor runs great. No white smoke, no excess moisture in exhaust, plugs DO get black rather quickly like 1200 miles, I think because it burns some oil. It will hold at 251F in idle on hot day in Florida without thermostat. But if I drive around town it goes 260F & I shut it down. I guess best next test is should be for gases in coolant? Then after new tank arrives pressure test the system? Thanks again Bruce for your help I really appreciate it!!

Hi Folks, My name is Jim, I'm happy to be a new member of the Caddy lovers club! I'm 54, been a caddy lover since my teens when my dad got his 4th or 5th caddy. In my 20s He came across a beautiful late 60s red convertible with a white leather interior which he slapped some plates on & let me take her for a ride to have my tooth pulled. He neglected/forgot to tell me the brakes were non existent brakes (master cylinder) so I used the emergency brake, made it to the dentist & home! Ever since that & my dad's subsequent Cadillacs I've been hooked on em. I've had 3 or 4 Devilles & I currently own a 97 I've had for 3 years. It has 214,000 miles on it. It was not well maintained, unfortunately. Most Cadillacs are big, solid built cars that have great comfort, quality motors & I feel safe having my wife drive one with our kids in the car. That was a funny post about trading the Caddy in for a Daewoo! I have a 2002 Nubiro that's a piece of, you know. That topic post was from 2004 I think. Anyways here's my situation. My 97 Deville 4.6 Nothstar Y is bubbling over 251-260 degrees. I have leaks in the pressure tank & have ordered a new one. My question to you experts out there is the leaking tank enough to cause overheating due to loss of pressure? I am not a mechanic though I can remove & replace parts, swap motors, etc. but I'm not a cooling system guru! I am concerned it may be a head gasket issue. I checked the exauste pipe, no moisture. Oil & coolant are clean, purge pipe open, water pump ok(replaced last year & removed cover to check), new stat, good hoses. I have not been able to perform a pressure test not have I checked for combustion gases yet. I think it's the pressure tank leak (at the filler neck & at the purge hose) causing overheating & certainly loss of coolant? Can you guys help me out please? Thank you!!