BodybyFisher

1991 Eldorado & Seville Service Manual

1994 Deville/Eldorado/Seville Service Manual

1996 Deville/Eldorado/Seville Service Manual

1988 Eldorado/Seville Service Information Manual

1988 Product Service Publications

Hydra-matic 4T80-E transmission technicians guide

110 years of Cadillac (Assouline) history 

Northstar waterpump socket (cast unit not stamped)

Northstar flexplate lock 

1996 Cadillac dealer brochure detailing all models

Cadillac 1950s (55/56 a guess) original bulb kit in box.

Tech 2 OBD 1 and 2 reader, bi-directional capability, live data  (knock off unit) no programming capability 

These items have served me well and should be with someone who needs them. 

If there is any interest direct message me for prices, condition and photos.  

Glad to hear it

First I have ever heard of anything like this.

Sounds like you have narrowed down the problem. 

Do this when you get a moment, tear off the end tank (bend the tabs/flange) on the intake side and look at the cross tubes, my gut tells me they are going to be gunked up.  

I would have the engine professionally reverse flushed if you are finding rust.  Dumb question I don't know the answer to >> does the LT1 have cast iron heads?

2 hours ago, adallak said:

 

You are so right. 

2 hours ago, adallak said:

The common failure of GM radiators of 90sn has been a crack in the plastic radiator side tank. I have replaced it 11 years ago (just the side tank) and hoped I would never have another issue with the cooling system.  Well the pump stated to leak 3 years an 11,000 miles ago and according to the records it was replaced some 50,000 miles ago by the original owner or his dealership.

The pump will arrive on July 7. Before that, it does not make sense to touch the cooling system. Will update, of course. 

July 7th, my birthday!  70!  I am hoping for a 70th edition C8, we will see 🙏😄

The learning never stops.  If this 11,000 mile waterpump is toast already things are worse than I thought.   Do you recall where it was made?  You can't even assume an 11K part is good anymore, amazing.  

Can't wait to see the result here 

You gotta stop winding that Fleetwood out to 9,000 RPM Adallak lol

PLASTIC?  I'm looking forward to the solution on this one, Armen 🍿🍿🍿

I would buy the Harbor freight block tester and test the coolant, to eliminate that from the potential list of problems.  

While at idle check that the upper hose is holding pressure.

If the upper hose were cold it would indicate that no coolant flowed through it.  

11,000 miles on the pump should eliminate that unless the impeller backed off but that would be a fluke.  

I can't help but think the radiator is plugged and gunked up.  

56 minutes ago, adallak said:

😂😂😂. 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. 

Keeping my fingers crossed you get back to a cool 181° 👌 good luck with that radiator swap

36 minutes ago, adallak said:

Ordered a new radiator. 

I think that is a smart thing to do.  It is very possible that years of cooling system tablets has built up and is clogging up the radiator.  

Looking forward to your results.

Don't forget to add more tablets 😉😀 I also didn't think the 5.7 needed the tablets, I know the 4.9 and NS needed them.

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

Yea the easiest thing to do would be to buy an ac Delco thermostat to eliminate that possibility.   

Air in the system will cause bad heat and overheating if anything.  

3 hours ago, adallak said:

The fans are fine, they turn on as they supposed to do if I let the temperatures climb. The cardboard is on the other side of the radiator. 

Ok, so you don't have a fan clutch.  You have electric fans.  Are they turning on 100%, because of a fault in say the AC compressor?  Some faults cause the fans to default on when they shouldn't be on at all for safety.   Can you pull codes? 

I just edited my comment reread it regarding the fan clutch

Yea, I hear ya, but you replaced the thermostat with a 180.  A 180° stat begins to open at 180°.  If you are getting 167, the stat should not be open, causing the temp to continue to climb.  Are you sure it doesn't take a 190° and not 180° stat and the old one was hanging open?

One other thing could be possible, is a locked fan clutch in combination with the cool ambient temps.   This might be supported by your temps increasing when you blocked radiator air flow.

So it seems that you feel that your temp is actually low based on heater output and the upper radiator hose.  You are in Massachusetts?

3 hours ago, adallak said:

Thank you, gentlemen. Checking out the sensors never hurts. I wish the one associated with the diagnostics display were easy to get to. I'll update if I find out something. 

The coolant temperature sensor is hard to get to?   It wouldn't need to drift much to throw you off 10-15 degrees. That small of a drift might be below the threshold to set a code.  I am not sure if increased resistance from corrosion would increase or decrease the indicated temperature maybe the service manual would provide some idea.  

I can't imagine anything else that would cause a legitimate drop in temperature, so it has to be a false reading.

3 hours ago, Göran W said:

Hi BbF. Don´t be a stranger!

Hello Göran, I am currently driving a Jeep Library and it's painful need to get a Cadillac asap.  I have become an F1 racing fan and am thrilled Cadillac is planning to get involved.  I better stop by more, the system has me tagged as a rookie 😉🤣 , thanks

This sounds awesome >>

Explain what you mean by, your mass air flow sensor 'went out'. 

What code were you getting?

What symptoms were you getting?

What was the full 'idle air' message?  What code were you getting?

It sounds to me that you are parts replacing.

What codes are you getting currently?   You should do nothing without checking for codes first.

Have you disconnected the battery to let the system go through a relearn?

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.  

I haven't been around for awhile.  The board looks different.  

I don't see the profile and message areas for my screen name what am I missing, was it eliminated or in a different spot?  It used to be at the top of the screen on the right.  

Thanks

23 hours ago, Chris Pranis said:

This is what im looking at doing....i tried sending you a message but it says you dont recieve them. Sorry to revive an old thread

I do get messages not sure what you did.   What is your question.  What is your year and model

32 minutes ago, SteveW said:

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.

That is interesting.  Ill go into the manual and see if there are any related codes associated with a P0741, thanks

This should be unrelated to a P0741.  If it were due to leakage it wouldn't have been affected for sure.  But maybe its possible during your investigation of the P0101 code you accidently reset or disturbed (in a good way) the main transmission plug improving its connection.  

The P0741 sets when the computer detects a greater than 250 rpm slip in the lock up torque converter.  

Within that main plug are connections for the TCC solenoid.

Did you clean any grounds maybe?

Keep us updated as to whether or not it comes back

I can't help to think that this is resistance in the power side and not the ground side.  

Gonna watch your progress.