: 2003 Deville - exhaust steaming and coolant loss

05-11-14, 07:56 PM
Hello all - my 2003 Cadillac Deville has the following symptoms. The Cat kept getting clogged so I removed it until I could figure out the cause. Now I am seeing the white smoke coming out of my exhaust. The car misses very seldom but does "miss" once in a while. The car does not overheat at all. My coolant is disappearing but I'm not sure where it's going. I plan to have a block test done on it tomorrow - as it's strange that the temperature guage is right in the middle of where it should be. Any ideas ?

05-11-14, 09:41 PM
It don't sounds good, but see what the block test says. That said, seeing as you are NOT overheating I would expect the test to come back negative.

When exactly are you seeing steam from the exhaust? At start up? Idle?

05-12-14, 02:12 PM
most likely hg but like ranger said block test will confirm or not

05-13-14, 01:53 PM
Hi All - thanks for the reply , i will post again here in a couple of days. One interesting thing i read to is that when the Head Gasket starts to go , the exhaust vapors enter the cooling system and the cooling sensor gets a false reading thinking the coolant is low when it is not. Not sure if this happened to some of you that hhad block issues. I'm beginning to think alot of the issues reported for the Cadillac Northstar are due to head gasket leaks. I also noticed, if i drive the car nicely, i get minimal if no white smoke out the tailpipe. If i drive it aggressively, it starts pouring out the tailpipe. After Cat was removed, Car drove 100% better went from NO power to FULL power. I'm guess the contaminants like oil, coolant is clogging the Cat. I've heard the ol "floor it to blow crud out the engine" , honestly, i think all this is doing is blowing crud out of the Cat and freeing up blocked honeycombs in your Cat. As when the Cat was removed, 90% of the honeycombs were clogged with black exhaust stuff.

05-13-14, 02:47 PM
Don't hang your hat on your previous post. Please go to the stickys and read the threads on fans, cooling systems, gauge operation and head gasket failure.

A common sequence, in head gasket failure, is that exhaust gas enters the cooling system, thus raising system pressure, blowing off coolant, the water pump cavitates and the engine overheats. You may or may not ever see a "Check coolant level" message.

A broken water pump drive belt simply overheats the engine, blowing off coolant.

A clogged purge line (cooling system high point air/gas bleed) causes "air" pockets in the coolant - one gets to the centrifugal water pump, it stops pumping and the engine overheats exactly like a broken water pump belt would cause. A common symptom of a clogged purge line is no heat from the HVAC but an overheating engine - the heater core is airbound, and that circuit plays a BIG part in maintaining correct coolant flow to the water pump.

Your cat may have been clogged - coolant MIGHT have been the culprit - but you now have an illegal car with a slew more trouble codes being saved in memory. The car will never pass emissions or qualify for legal resale.

05-13-14, 08:21 PM
Good points but #1 my car is not overheating and is running cool as a cucumber. #2 i removed the clogged cat and put a straight pipe until i can figure out what is causing the Cat to clog. As after 1 month , it is clogged again and thus NO Power. I have a 5 year warranty on my old Cat, so i can install a new one anytime for free. For those of you wanting to know what happens on a Cat removed, here is my experience with it: Exhaust smell: Yes (but less than when the Cat was clogged), Generates Codes: No. Louder: No. More Emissions Pollution: No except for the white steam i think i am getting from the head (still trying to confirm). Honestly i was getting a worse smell before removing the Cat because the Cat was clogged and causing exhaust to backup in the engine and cabin of the car. Like some of you, the car also uses excessive oil - but dealer has no idea why (no leaks). And yes, the Cat will go back on very soon , again, i am troubleshooting it trying to figure out why it keeps clogging. As soon as the tests are complete and the cause is identified, the Cat will go back on. My Caddy tech told me if Dex coolant is leaking in the engine block and out the exhaust, Dex will clog up the Cat very quickly. This might be what is happening.

05-13-14, 09:35 PM
One interesting thing i read to is that when the Head Gasket starts to go , the exhaust vapors enter the cooling system and the cooling sensor gets a false reading thinking the coolant is low when it is not.
Not true. Any vapors entering the surge tank will vent out the overflow once the cap pressure is exceeded. When it overheats or gets over pressurized and blows coolant out the overflow, that's when you get a low coolant message and you can believe it is true. Occasionally you will have a bad sensor (as I do) and get that message erroneously. My tank will be getting replaced tomorrow.

If you are leaking and steaming coolant out of the pipes, eventually you will run low and overheat.

05-14-14, 08:23 AM
Not trying to be a "Debbie Downer", my sons 98 started with the 'coolant low' alarms, (coolant wasn't low), white smoke out of the exhaust, engine temp was still good, then more white smoke, the end....head gaskets, overheating, runs rough, coolant in the oil. Re-manufactured engine on the way.

05-14-14, 08:26 AM
FWIW, a false low coolant message is caused by a sticking float in the surge tank, not HG issues.

05-14-14, 08:31 AM
Ranger - pls post if your fill tank replacement / sensor replacement resolves your issue. I've read in previous threads that others felt the tank / sensor was the issue but was not. It's possible i may be having the same issue, but my tech sees no leaks at the tank (neither do i). Thanks.


jamie, will the reman engine be drill / tapped with new head gasket bolts to prevent the head gasket from leaking again?

05-14-14, 08:32 AM
Ranger has a stuck float in his tank causing a false low coolant warning.

If the tank isn't leaking, and you aren't getting false low coolant warnings, you don't need a new tank.

05-14-14, 09:53 AM
:yeah: I am 100% sure it is a sticky float and a false coolant level warning message. Going out to change it in a few minutes.

05-14-14, 08:25 PM
Well - i cheated. A forgot to mention a few days ago i bought K-Seal , poured it in the radiator fill tank but it didn't immediately work. I read another post where someone said it took a few days for it to "kick in". Well, looks like K-Seal just kicked in today prior to the Block Test. I did get the Block Test at Autozone, bought the test fluid, performed the test, and Wella - test came back negative (head gasket is fine). I did the test 3 times also - all negative. Then i noticed no more white smoke from my muffler and the coolant was no longer dropping. So K-Seal may have temp fixed the head gasket issue , but as we all know it may not last very long. I will just have to monitor it and see. Interestingly, it did turn my coolant a Pink color and my heater core still works fine. So I was planning to buy a new car at the end of summer (and trade this one) - so if it lasts thru the summer i will be happy. K-Seal was $12.99 at Advance Auto. Again, not sure how long it will last - when it fails i will post again here.

BTW - how do you replace the float in the coolant fill tank , as i believe mine is also bad. Is there a link for that please? Appreciate everyone's input also. Thanks.

05-14-14, 09:04 PM
You might get through the summer (if you're lucky).

05-15-14, 01:28 PM
You cannot replace the coolant level sensor (magnetic) float. Tank replacement. The float moves only about 3/4".

You can just see the green float and reed switch level sensor connector in this lens-distorted shot of a Seville surge tank .............