Cadillac Owners Forum banner

1 - 16 of 16 Posts

·
Registered
Cadillac
Joined
·
5 Posts
Discussion Starter #1
OK here's another overheat problem that I can't figure out. I know you're all going to tell me about HG probs, but I don't this time. Had a new waterpump and therm.and cap put in about 5 mos. ago because it was leaking out of the pump. Put the car back on the road and it has been better than great. 2 weeks ago it overheated and blew out all the coolant. I replaced the dex and it seemed fine. Now it overheats in stop and go but will hang at 196 on the freeway for 25 miles then go up to 206. Runs strong and smooth , no whitesmoke out the pipe at start up, no oil in the coolant. Had a mech do that exhaust gas test at the purge tank and he said it's a busted HG. How can this be..
PS it's been over a 108 degrees here lately.
 

·
Registered
1996 Deville (sold), 2000 Mustang GT
Joined
·
1,300 Posts
A blown headgasket will push all the coolant out the overflow.If a trust worthy mechanic did an exhaust gas test and found exhaust gases in the coolant than it is your headgasket. No if's, and's, or but's about it.
 
D

·
Guest
Joined
·
0 Posts
Oh and you may not see white smoke out the exhaust and probably will not see any oil/coolant mixing with a Northstar. Car would probably still make an ok short distance car, even with a blown headgasket. How many cars can do that?. :thumbsup:
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
87,074 Posts
Coolant in the oil is rare in the Northstar.

It is probably in the early stages. Overheating will slowly get worse. As will coolant usage and exhaust steam if left alone.
 

·
Registered
Cadillac
Joined
·
5 Posts
Discussion Starter #5
I still don't understand why it runs cool on the freeway at 75 or 80 , I just can't believe it would happen so suddenly.
 

·
Registered
Cadillac
Joined
·
5 Posts
Discussion Starter #6
Oh and that test, I thought the test fluid was supposed to turn bright green ? It was very light, also it sits all night with no steam in the AM start up. How long would it take to O/H after running? And last, how long do I have before it's undrivable.....
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
87,074 Posts
If you doubt the coolant gas test, do a cylinder pressure test. That is fool proof, one way or the other.
 

·
Registered
1997, 2003 deville
Joined
·
4 Posts
I agree with Destroyer, depending on where you live, it still makes a good short distance car. I have a 97 Deville with digital readout. (The readout probably saved my engine.) It overheated in the hills of West Virginia. Took it to Ohio and back through Tennessee on I-95. I kept the heater on all the way back to south Georgia. Currently overheats only on steep hills. At some point I may replace head gasket. What I found interesting is that I got 29 miles to the gallon coming back averaging 70 mph. The car has 180,000 miles of which I have put 140,000 on it and in all that time I never got 29 mpg! Any thoughts on that?
 
D

·
Guest
Joined
·
0 Posts
At some point I may replace head gasket. What I found interesting is that I got 29 miles to the gallon coming back averaging 70 mph. The car has 180,000 miles of which I have put 140,000 on it and in all that time I never got 29 mpg! Any thoughts on that?
Hmmm, well uhhh, no, no thoughts on that strange happening. :alchi:
 

·
Registered
94 ETC,97 STS
Joined
·
3,531 Posts
shadow765,

Many of us have gone through this scenario before you.

The N* is designed differently than old V8's. If you look at a picture of the block you will see why coolant doesn't readily mix with the oil.

Generally at the initial failure there is still some pressure on the gasket. Under light load it may not leak. Uphill or on hard acceleration it will blow past the gasket.

No one can tell you how long you can drive it as is but it can be a long time if you use it for short trips, live in a fairly level place and watch for the point that the oil gets contaminated.

Jahtem, you are concerned about it overheating so you are driving it conservatively...good for gas mileage!
 

·
Registered
Cadillac
Joined
·
5 Posts
Discussion Starter #12
Well I did park next to a Corvette awhile back....seriously, right now it seems I've got a grocery getter that I owe 6000 on , can I do something to make it last a few mo's till I can dump it at auction, 18lb tank cap, bigger radiator, any kind of stop leak, anything?
 

·
Registered
1996 Deville (sold), 2000 Mustang GT
Joined
·
1,300 Posts
There isn't any cheap fix, nothing. If you still owe money on the car, I would strongly suggest you DON'T drive it. The overheating will start to get worse and worse, and once it hits 250-265 you will fry all the oil in the engine, and really run the risk of cracking a block, or head, or warping a head, making the repair alot more expensive. Your best bet is to spend the 3000 to fix it, or pay it off, and trade it in before it starts overheating everytime you drive it.
 

·
Registered
Cadillac
Joined
·
5 Posts
Discussion Starter #14
OK, thanks to all for the input, I'm just very bummed, I have always been a product enthusiast, this will be my 4th starting with a Champagne 1970 De Ville convertable I drove in college. Has this problem been addressed in the later years ? Can any of you suggest a model/year that has a good record? I just can see me driving a f--king Toyota.....
 
D

·
Guest
Joined
·
0 Posts
OK, thanks to all for the input, I'm just very bummed, I have always been a product enthusiast, this will be my 4th starting with a Champagne 1970 De Ville convertable I drove in college. Has this problem been addressed in the later years ? Can any of you suggest a model/year that has a good record? I just can see me driving a f--king Toyota.....
Supposedly the head gasket issue was addressed for the '00 model year. You'd never know it hanging in here though as there are many '00-'02 models surfacing with the dreaded head gasket issue. If its got a Northstar, steer away from it like I do.
 

·
Registered
1996 Deville (sold), 2000 Mustang GT
Joined
·
1,300 Posts
Yea it is definetly a shitty thing to deal with. The repair will cost half of the payoff or more, definetly need to put some thought into what you want to do with it. The 93-96 Fleetwoods are far more reliable than the deville, and have an LT-1 (corvette motor). And a toyota isn't as bad as you think. There's currently 4 in my family, one was mine and i never had an issue with it,ever.
 
1 - 16 of 16 Posts
Top