BodybyFisher

Another update. 
I have ruled out the recently replaced thermostat, but IT was the problem. It gradually failed within a few months. 
Will keep the new radiator anyway. 
On the side note. I am in Pittsfield, MA now and for some reason people of this town are particularly in love with 1993-1996 Fleetwoods. People stop by and ask if it is for sale quite often. It will be for sale eventually within a year, but not right now. 

The car is fixed. The new radiator did it. All the temps are back to normal. Have not taken it for a long ride, but I do hope everything will be fine. 
Is it okay to keep only distilled water in the system for a few more days? I want to drain as much of rusty old coolant out of the system. 
I am still thinking of removing those stupid knock sensors/drain plugs to do a proper flush and drain. 
If I do break them (most likely I will), can I use broken sensors to fool the computer? 

Are you using Dexcool or traditional green coolant?
Dexcool can cause rusting in the air pockets on iron blocks. Long known problem. 
Personally I use the good old fashion green stuff in everything. 

Update. I have replaced the radiator. Pieces of rusted junk came out of the system. Cannot flush it, unfortunately. This time coolant looks reddish, rusty... Nothing seems to be wrong with the water pump. At least the (steel) impeller does not spin 9b the shaft. Nevertheless, I am planning to replace the pump, stat, radiator cap, and the temperature sensor.
If it was indeed the rust, it will build up sooner or later. Need to get out of friend's place. Probably will have to take to a shop for a flush if the problem persists. 
 

Never worked on a LT1 pump. I think the cover comes right off and uses a o-ring. But I think the impeller is pressed on. But it may allow you to at least see if anything looks amiss.
Lot's on Google and Google Images. Corvette...z28 etc..
 
It is a reverse flow pump.....so you might have to think about what the flow is doing...
 
https://www.corvetteactioncenter.com/tech/knowledgebase/article/1992-1996-corvette-technical-article-lt1-reverse-flow-cooling-system-526.html
  How does a lt1 water pump work?     Coolant flows from the lower radiator hose into the water pump at the thermostat through the heads on the way to the block. The reverse flow pump acts as a vacuum pump in drawing the water out of the block. It then passes the thermostat and returns it to the radiator via the upper hose.

I don't think the pump is doing anything.....saw one of LT1 post where the impeller was just spinning on the shaft. 

I would take a close look at the water pump impeller. Some pumps are actually using plastic ones. The pump could also be a counterfeit Gates.  
https://www.impalassforum.com/threads/water-pump-impeller.341985/

😂😂😂. Tablets were BIG on this board! No, for the last 12 years there were no tablets in the system. It is the rust, I believe. We will see. 

Yes, a change in operating temps is suspect.  That said, 10 degrees above thermostat temp for cruise is expected.  If thermostat at 185F it should always have operated at least at that level?
Are the fans both coming on?  Does it get hotter than normal at idle as well?  Is the radiator clear?  Could it be time to flush or replace the radiator?

You have no misfire or vapor out of the exhaust, so my initial feeling is no blown headgasket.  You can use the block tester to test for hydrocarbons in the cooling system, I recently saw the block tester kit at Harbor Freight at a good price compared to the $50 balkamp make.  
You have checked to make sure all air is out and you aren't getting cavitation?
Intermittent fans, might be difficult to diagnose if a fan motor is stopping when it should run.  
Check the lower hose for collapsing
How old is the radiator?
I don't think 195 is anything to panic over, even though you saw lower temps yesterday.  AC is operative? 
Check for "tar paper" material blowing over the radiator partially restricting the air flow through the radiator. 
Are you getting any transmission codes?  A slipping torque convertor clutch might generate more heat. 
Just brain storming here.

Thanks Göran

Hallo,ich weiß der Betrag ist alt.
Aber könnte mir jemand die Software per E-Mail schicken?
Das wäre super 👍

FYI. US version does not work in Europa.

Thank you, gentlemen. I'll update if/when I find the problem. Nice to be  back to the board. 

I completely agree on the delco tstat. The quality of so many things has been so bad that words cannot describe, and what's worse is nobody seems to care. I have been trying to find and use old stock whenever I can

Welcome Back.
I suggest replacing the coolant temp sensor. I say this in reading the original thread and replies that followed. Hot and cold swings over time, bumps and bangs, etc... can have an effect on a sensors ability to be accurate. Ie resistance value slightly off. Do not go with aftermarket if at all possible. I have not had good luck with them being accurate

Hi Armen, I got your PM.  I initially felt that your stat was open till I read this thread.   I tend to agree with cdgrinci, I would pull the connector off the engine temp sensor and check its resistance.  If the sensor resistance drifted it would be reported wrong to the PCM and the PCM would report the temp wrong to you.  Even a little corrosion on the contacts could increase resistance.  If you have the service manual the resistance number should be in there, get your ohm meter out and test it at the proper temp shown in the manual.  Also test it at operating temp.  Mike
Hello everyone I hope all are doing fine.  I am eying an XTS/CTS coupe, so I may be back one day soon.  

Hi BbF. Don´t be a stranger!

is it possible the radiator fans are coming on too soon, or  running on high all the time?

Perhaps a bad temp sensor?  Your thermostat has tested correctly so it should warm your engine to the set reading of, pretty close to, 180.

A picture of my "new" Fleetline

This catch-up post was a lovely Christmas present for the Forum; thank you for posting.  I would love to have a roadster to tinker with along with my ATS-V, but will have to wait for the right one to come along.  Good luck in your Garage search.

Hi! 
I just wanted to re-introduce myself since it was a long time ago.
I'm a male, 46 years old, with wife and a daughter, nine years old. I don't really consider myself to be one of the lucky guys in the world but I'm not a very social kind of person and that goes hand in hand. I have been unemployed the latest two recessions for a couple of years (in Sweden it is the last guy employed who is the first guy who gets sacked when a company needs to shrink their employee force) and have moved around quite a bit (in Sweden) just to keep myself occupied. You know the kind, the guy with few personal connections who has to take the job no one else in their right minds will take. Some organization theorists believe that there are three kinds of people, the guy who just tags along, the guy who likes to be in charge and me, the guy who likes to be the specialist.
I'm working as a mechanical engineer (currently on a company producing labels and my department is manufacturing labeling machines with me as the head engineer). I develop all new equipment even if the whole department take credit from my achievements, especially if they weren’t involved in the process at all, like sales people, my boss etc. My wife is a nurse specialized in cancer treatment (half boss too). Anyway we had to commute so the time to do fun things like working on cars, write on forums etc. was limited. We live in a small town because we really don't want to live in a violent and criminal town like Malmoe (where I am working). The Covid-19 outbreak forced me to work from home which by the way suits me just fine since I can't stand half of the people on my department (not to mention being in Malmoe) I've been working as a mechanical engineer in almost 25 years and have NEVER been surrounded by so many freeloaders. I swear that if the management kicked half of the employees we couldn't tell the difference! As an example we had an inventory of the stock the other day, on guy was "sick", a girl aged about 25 complained about that she was not supposed to be there because it wasn't her job, and also complained about her nails being damaged from counting O-rings and washers. I told her to shut up and count how many spring turns there are on the spring and work instead of complaining. 😉 
I've been on the Caddy info forum since 2002 and have owned an Eldorado (1988 year model with about 150k miles on in when sold, 50 k miles from my driving) a 1993 STS (with about 150 k on it when sold, 50 k miles from my driving) a 2002 STS (about 210 k miles on in when sold, 190 k from my driving) and am the happy owner of a 2012 CTS-V. The V currently has about 100 k on the odometer (70 k miles from me). Our family (daughter, wife and me) also like Jeeps. We have owned a 1990 Cherokee, a 2004 Wrangler and the latest one was bought last year. A 1999 Grand Cherokee. Of course people think that we are insane when we buy a 20 year old car with almost 200k on the odometer but I saw it as a recreational project. 
I always try to do as much as possible by myself when I work on our cars. No need to pay someone to damage or mistreat the car, I can do a better work for free. I only have access to a very small garage. Just enough space to change oil, brake pads and other small stuff. On the Jeep I've replaced all cooler lines and hoses, alternator, AC-compressor, radiators, brake pads and discs, brake booster, rear exhaust system, fan coupling, some sensors and electrical motors too. Payed the local shop to do the brake lines and rusted out door sills and some other small stuff. Now we have a 4wd in “daily drive condition” and a car that we use in terrain and all year around costing $0 in financing. Just got to fix the leaking valve gaskets and some minor stuff. We used it on a 3000 mile drive this vacation without the slightest problem. Now I thought it was the time to buy an older car. I bought a 1949 Chevrolet Fleetline in "daily driver" condition and I am planning to keep it in OEM condition. Unfortunately it is hard to get access to garages in Sweden and I'm searching for a garage to store it and work on it. I have the car stored by the seller at the moment and can go there to do minor work on the car but it is always better to have the car in the near vicinity than 30 miles away. I think it is in need of only smaller work. Adjusting valves, ignition and carburetor, get the clock and speedometer to work and other small stuff like that. Great car, but it is not a Cadillac. I figured that I already have a performance driver so it will be fun driving a Chevrolet anyway
The car has an inline overhead valve six with about 90 bhp, three on a tree (first gear unsynchronized), no oil filter (option in the day) and an AM-radio, 6 Volt electrical system and vacuum wipers, no servo steering or servo brakes but it is solid running, no mechanical noises and reasonable rust free. I just love it

 

Hi Guys, sorry was abroad for 2 weeks for work but now here the news:
I disconnected the vacuum tube started car and moved out of neutral and there was solid vacuum!
So i ordered the diaphragm! will keep you updated
best regards from the Cadillac front
 

I don't think the PCV hose vacuum leak was related but, perhaps the damaged MAP was. The MAP on that car tells the ECU what load is on the engine. If MAP thinks the load is higher, the ECU would adjust shift points and RPM accordingly. When the car reached 41 MPH, the ECU turned on the TCC but, the engine speed was improperly elevated due to misreporting by the MAP.  Maybe this tricked the ECU to think the elevated RPM was due to slippage. That's my theory anyway.
Didn't touch TCU connections or grounds.