Temperature matter

[Marcel75]

Hi all,

I'm new on the forum, so short presentation: 62 y.o french american car enthusiast, I live in Paris and sometime in Alsace near german border. I use to drive in a nice 1970 Eldorado acquired new by an american doctor in California in November 1969.
Car running perfect so far but...
Last sunday, after some trip, back home and opening the hood when motor stopped for overall check, I noticed some boiling of liquid in the upper part of the right hand ramp of cylinders. Hum,  .
I let the motor cooling. It took 15' or so to stop boiling noise. Moreover, while cooling down, the upper hose got flattened for a while and then recovered normal shape.
No loss of liquid, temp. 70 C (160 F) while driving, climbing to 85 C (185 F) on idle waiting to park in my garage. Probably more when motor stopped?
Wonder what it could be, hope not a cylinder head gasket. I did not try to restart engine since I'd prefer to understand what the problem is before.
Anyone of hou have some idea regarding that?
Thanks,
Marcel

[James Landi]

Here are some suggestions:   When you turn off you engine after a long run, there is no water or cooling air flow, so residual heat is common and natural; however, boiling of the coolant is not a good sign...Your car is designed to suck coolant from the reserve tank when it first starts up after being cold.  A collapsed upper radiator hose MIGHT indicate that simply changing your radiator cap or (PERHAPS) cleaning the area where the cap screws into the radiator will allow coolant to enter the system.  I suggest that you remove the radiator cap, and start the engine when it is cold... using a focused light, look down into the radiator... and be prepared to add coolant, as you may find that you need quite a bit to fill the system IF your radiator cap is not functioning correctly. In any case, if you have not serviced the cooling system for many years, you may wish to consider flushing the system and adding new coolant.  You are correct to be concerned.   James 

[Marcel75]

Hi James,

Many thanks for prompt reply, bet it is night time in US... I agree coolant is about to be somewhat hot when engine stops but, as you mentionned, boiling is worrying.
Radiator is new from last year with a 16 psi cap (ca 1.1 bar) so coolant circuit was cleaned at that time, alu radiator, 7 blades fan standard Eldorado 500 cu.in.
I'll try to restart engine today and come back later on the topic for more input...
Thks again for your kind cooperation.
Marcel

[Bobby B]

Marcel,
Hi. First thing I would be doing at this point is a compression check, as you will be chasing your tail with intermittent problems that seem to come and go but never get resolved, if it is indeed a leak, or small leak within the head gasket sealing area. If that proves negative, you have a punch list of detective work you need to do, and I would start by taking temperature readings using and infra-red temperature gun at various points along the coolant path from the time the car is started, up to the point that it starts to act up. Shoot the radiator at different locations, the hoses, pump, and of course the cylinder heads at various locations. Surprisingly, I've had more than a few slipping impellers on brand new water pumps, new collapsed hoses, etc. "New" does not necessarily mean anything anymore in today's aftermarket parts world. Narrow it down starting with a compression check ASAP.  Good Luck and keep us posted with any little details you might notice.
                                                                                                                                                         Bobby

[James Landi]

Bobby,

With all due respect regarding your suggestion, if Marcel had a head gasket leak, he'd be blowing coolant out of his radiator or his engine oil would be polluted with coolant.  He did mention that he has a new radiator -- perhaps he has a clutch fan that might be causing an over heat condition, or his radiator might not yet be filled to capacity.  A collapsed upper hose suggests that his cooling system is not leaking-- has vacuum.  ALas, I own a 4100 Cadillac  that only had a leaky head gasket during start up... then it would push coolant out for a minute or two ... when warm, it had perfect compression, all this is to say, I would suggest Marcel take a careful look to make sure he has a filled cooling system--- he could run the engine with the radiator cap off and see if he has bubbles from escaping exhaust gas.. another approach.  What do you think?  James

[Scot Minesinger]

What does the boiling mean, just that the car is running too hot or the system fails to maintain pressure (ie. boils at 212'F)?  I have seen other Cadillacs run fine for hours with no known coolant leaks, stop, you hear the boiling, and the white tank fills to higher level, then an hour later no loss of fluid and reservoir is level it should be.

[Marcel75]

Back for some news.
First, thanks for your implication, I appreciate.
I eventually restart engine this afternoon and let motor warm up idle or with smooth pressure on gas pedal. No bubbling in coolant circuit, ~ equal heat at every point after thermostat opening, no hoose collapse and....no boiling. Found hooses quite hot but not overpressured. Fan ran well, continously. Level in reservoir went up to max and then lowered after engine stops.
Well, I do prefer that but still wonder what happened on sunday? Maybe Scot is right, and I should not worry in excess. To be noted that it is quite hot in France these days (up to 105 F) I have an additional electrical fan fitted in front of the condenser giving some strong additional air when needed but I dit not use it last sunday since I was not in traffic jam or so. Maybe I should have, taking in account outside temp.
Some pictures of my car: (Nottingham green firemist, medium red leather, no vinyl roof)

[James Landi]

Marcel,

It's good of you to provide us with an update and pcitures-- Merci...from all that you've reported, the car may be fine.  While it's not healthy to be overly anxious, your continuing concerns are justified, so checking and making sure that all is well is never a wasted effort with very old cars.  Best regards, James (Up here in Maine, where the temperatures are in the upper 70's!)

[Scot Minesinger]

Sorry to mislead, was more hi-jacking your post a little - sorry.  Just asking why does the car boil and what does that mean.  Boils when the car is shut off?  One Cadillac does and the other does not?  Not saying boiling is OK, just asking if it is OK?

[Marcel75]

No problem Scot, I caught the hidden face of your post. I realized that I just had to run engine again and test. Obviously, boil is not good and I must keep in mind, in line with James, that even if it seems to be ok today, that does not mean that problem is definitely over....
Thanks again for your help to a green horned french  in Cadillac world. 

[Bobby B]

Bobby,

With all due respect regarding your suggestion, if Marcel had a head gasket leak, he'd be blowing coolant out of his radiator or his engine oil would be polluted with coolant.  James

James, 
  With all due respect regarding your diagnosis, it is not necessarily true. I've seen it many times…….
                                                                                                                        Bobby

[Marcel75]

Bobby and James,

I think both of you are right: depending where the gasket failure is you can get either a problem with cooling liquid (vapour, loose of coolant, white smoke out of exhaust, bubbling in circuit) or with oil circuit (loose of oil, traces of oil in cooling liquid). You can get even a loose of compression for 2 cylinders (failure in circular part between 2 cylinders) and, the worst (failure between one cylinder and water circuit), water inside cylinder which blocks the piston due to incompressibility and bye bye connecting rod and more...
Regards,

Marcel

[Bill Young]

Marcel , Beautiful car! , Was the Nottingham green original?

[Marcel75]

Yes Bill, it was. 96 color code as well as 488B trim code on alu identification tag.
Unusual fitting with the red trim as Nottingham green appears usually with white interior.

[Bill Young]

Yes Marcel, The original Owner ordered Your Car for sure as the salesman had Data books supplied by Cadillac that had a grid showing suggested interior color trim codes with each color. Some were quite nice however not too adventurous . My Mother had such a Car as yours. A 1968 DeVille Convertible with a sandalwood interior and top which was reccomended to go with code 44 Chestnut Brown but Mom's Car was ordered with a code 30 Silverpine Green paint , Stunningly beautiful like Your Car.