I have a 92 DeVille with 142k+ miles. I have had very few problems with it and still seems to run fine, although since last winter I noticed gradual coolant loss. It was quite noticeable in winter and had to add good bit in the reservoir tank. It wasn't as bad as weather got warmer and in the summer it was barely noticeable. But come the fall with lower temperature the coolant starts to disappear again. There is no temp gauge in these cars so I can't even check for coolant temp. The coolant loss for now is very gradual; about half inch increment lower in the reservoir tank since topped off about 3 weeks ago (And I read the coolant levels in the morning after the car has been sat overnight). Is there anyone experiencing similar problem? Having lost another 92 DeVille to blown head gaskets a few years back, I'm really concerned. Any inputs would be appreciated.

Check all hoses in first place. And do you noticed any coolant drops under the car?

Check all hoses in first place. And do you noticed any coolant drops under the car?


I did, and there isn't any leak. It has been about two summers ago since the last coolant flush; would it be worth doing it now or should I take it to a shop and find out what's wrong with it instead?

I did, and there isn't any leak. It has been about two summers ago since the last coolant flush; would it be worth doing it now or should I take it to a shop and find out what's wrong with it instead?
In My Eldo was little leak from termostat connection - it was so small leak, that i find it only, when i changed termostat.
And you cant really see it, because its dropping to the hot engine and vapours quickly.
Maybe you have same problem?

In My Eldo was little leak from termostat connection - it was so small leak, that i find it only, when i changed termostat.
And you cant really see it, because its dropping to the hot engine and vapours quickly.
Maybe you have same problem?


I never thought about that... I'll have my mechanic have a look at that once I take it in. And hopefully that is the problem, and not the head gaskets.

If there is no white smoke from tailpipe and engine oil is clean (not oil/coolant mixture), then it must be leak somewhere - its not head gaskets fault.

Had exactly the same problem with my 1991 Grand Marquis with 220,000kms. Anyway my dad has it now, but it is still running great. I never thought it was serious enough to fix.

Common place I see coolant leaking on cars at work is air bleeder screws. You'll see this dried whitish powder around the bleed screw. Although I see this less with cars using the old style silicated coolant (the green stuff) rather than the new Dex-Cool coolant (the silicate free orange crap). I do not know where it they would be though on a FWD deville however. I don't even know if they exist on your car.

Check the water pump too. It could be leaking from there too.

I agree with vanaisa, check all the hoses and clamps. If they've never been replaced, replace them for sure. I would also suggest a coolant flush. It wont solve the loss problem, but the way the old style coolant works, its a good idea to change it more frequently as the car ages, as the coolant bonds chemically w/ the metals in the system to prevent corrosion of the system. If you want to know more, check out some recent back issues of Car and Driver. Patrick Bedard had two great columns 2 months in a row about coolant technology.

Could the coolant be somehow leaking into the engine oil?? I would consider THAT to be a major problem worth fixing. I also never noticed any leaks and inspected with a maglite around all gaskets.

I have a 92 DeVille with 142k+ miles. I have had very few problems with it and still seems to run fine, although since last winter I noticed gradual coolant loss. It was quite noticeable in winter and had to add good bit in the reservoir tank. It wasn't as bad as weather got warmer and in the summer it was barely noticeable. But come the fall with lower temperature the coolant starts to disappear again. There is no temp gauge in these cars so I can't even check for coolant temp. The coolant loss for now is very gradual; about half inch increment lower in the reservoir tank since topped off about 3 weeks ago (And I read the coolant levels in the morning after the car has been sat overnight). Is there anyone experiencing similar problem? Having lost another 92 DeVille to blown head gaskets a few years back, I'm really concerned. Any inputs would be appreciated.

Hi,

You can see the coolant temperature if you depress engine data on your driver information center. It shows RPM etc, push until it shows the temperature.

I have noticed a little crack at upper radiatore body. I have noticed the leak only after filling the radiatore and the reservour with additional coolant. I suppose I hea the same crack for a few years, just it did not let know becouse the coolant level was below the crack level. So I had some 9-10 quarts instead of 12.1. Not a big deal. My car is Sevillle 91 with 4.9 motor.

Armen

Remember, there are many hoses going over the engine where you wont notice the leak....... Hoses that leak over the V will make a puddle and will evaporate as it gets to operating temp......

Only way to find out is to go in there and go nuts.... And Id say, if it hasnt been done, the hoses are shot.....