: Is this the beginning of the end for my STS?

06-27-08, 03:54 AM
Background first, 1997 Seville STS. Elderly owned since new, bought about 3 months ago with 52k miles. Now has 55k miles. Didn't have one problem with it, mechanic who checked it out seemed impressed how clean it was.

Fast forward to about a week ago. I drive it about 45 minutes, slow traffic sometimes, eat (round 30 mins) then drive again 45 minutes smooth driving. Runs a little hot. About 1:00 maybe a little colder. But its gradually getting hotter and hotter. I get scared park it, and leave it til yesterday. Take it to a local mechanic and he tells me this is whats wrong, and the cost

Water crossover gaskets are leaking. I also need the Thermostat replaced since he says "Its needs to be since it ran warm". Coolant system flush, Thermostat seals and gaskets, and of course the water cross over gaskets. All that he quotes is 1200. Im thinking no way, this seems like a ripoff. Tells me I need new spark plugs and wires. Says 700 for that. Again Im thinking wow WAY too expensive

Called a few shops and both of them said that 1100 was WAY too much. It was only about 600-650 parts and labor. Labor was 5 and half hours. 1100 guy said 10.5 hours. So I picked up my car and took it to my regular mechanic, who can now see me

He looks it over, does the same tests they did, and he says he found SMALL leaks around the water pump, radiator. But he says nothing so severe he sees a huge problem. He, and this may not make sense cause I dont understand, tested it 20lbs, should run at 12 so it makes it seem like he drove it two hours. Didn't get hot on it. He told me hes gonna flush the radiator tomorrow, re test it, drive and then depending on if it doesn't leak bad, or doesn't run hot, he will put thermaseal or something and thats it

My questions are, is what Im talking about a HUGE panic attack type thing here? Is my engine fixing to blow a gasket? Or could it be it ran hot ONE time, and the small little leaks are no big deal, keep adding fluids once a month. Im SUPER nervous and super scared but he saids he doesnt think at all the engine got hurt. He never EVER even got close to being in the red. Did I overreact? Not sure

Also, sometimes when I first start the car, I will hear a tapping noise. But it doesn't sound like its coming from the engine. 1100 dollar guy said it might be the idler, but it didn't do it to him so he doesn't know

That cant be a engine problem can it? I mean it barely taps and then it goes away. And half the time it doesn't even do it.

Other than that the car runs perfect. It seems like 1100 guy tried taking me to the cleaners, and maybe I migt not even need the damn stuff he tried selling me.

Any help would be SUPER appreciated. Also, I checked the codes about a week ago, no codes. Need any more info please post it, or email me

Worried in Houston,

06-27-08, 12:29 PM
The tapping sounds like "cold Carbon Rap". Just needs to be take out and given a little tender loving WOT (beat the hell out of it).

The other problem could be anything from a clogged purge line to a head gasket starting to fail. It will need a competent diagnosis.

06-27-08, 01:27 PM
First things first. How hot did it get? Where on the temperature gauge was the needle? If you never overheated, you may have no problem at all - maybe just some minor leaks at the crossover. If the head gasket goes, usually all the coolant will blow out the surge tank

06-27-08, 02:35 PM
It only got about a quarter past the middle mark of the heat gauge. But I believe if I kept driving it it would have gotten hotter. Just my opinion though. Im waiting on the mechanic to call me today. My girlfriend says im a weenie and shouldn't worry since the car NEVER even got in the red area of overheating and it only happened once. lol not sure though

06-27-08, 04:27 PM
Your girlfriend might be correct. It is normal for the temp gauge to get 1/2 way between 12:00 and red zone - it is that point that the fans kick in if you don't have the AC on.

06-27-08, 04:39 PM
The fans kick on at 224 degrees. You will have to get a LOT hotter than that to do any damage.

06-27-08, 08:13 PM
In fact, it is pretty much impossible to damage the engine by overheating - it will go into camel mode and start shutting down cylinders once it gets to around 260

The fans kick on at 224 degrees. You will have to get a LOT hotter than that to do any damage.

06-27-08, 10:34 PM
260 degs is plenty to warp an Aluminum Head....

Crown Vic Owner
06-28-08, 12:37 AM
260 degs is plenty to warp an Aluminum Head....

This man speaks the ****in truth.

Guy never even redzoned the old motor that was in my SLS. Than again, i have gotten 4 or 5 stories about my previous motor.

06-28-08, 01:10 AM
Ok, what if my mechanic tomorrow tells me car is fine, no seepage or anything like that into engine, just very SMALL leaks that shouldn't be a problem. The car is SUPER mint, not a stain in the interior or nothing. Should I sell it, for what I paid for it, and get something else. Since mine is a 97, its destined to happen right. Just thought Id throw that out there, sell the damn thing, get something alot more reliable. Yay or Nay

06-28-08, 06:21 AM
It doesn't seem like you might have the nerves required to own a Cadillac. If every hiccup is going to send you orbital then I'd say sell it. If you want A-to-B transportation with no worries an 11 year old GM product is not for you, there are lots of Corollas out there. If you want to drive a Cadillac, pop a Xanax and have your mechanic drain and refill the coolant using 50/50 Dexcool + distilled water plus the Bars leak tabs per manufacturers recommendations and change the thermostat while the coolant is out. Drive for a while and see what happens.

And yes, your headgaskets are out there right now secretly plotting an inopportune demise :hide:, but only after you've invested much more time and money than you have so far...

06-28-08, 11:22 AM
a car with only 55k miles should be mint. i figure you bought it for 5k based on miles/age. if you are worried about things failing, than why didn't you buy a newer rig? say 2k or up?

06-28-08, 04:21 PM
lol Im not too worried about small stuff, what I AM worried about is a head gasket blowing and having to throw the car away or put another 7 grand into it.

But I did get an update from my mechanic. Says he hooked it up to the machine, and it was running 192, but the gauge on my dash said it was running a little hot. Also, and this has happened twice now. When the car gets SUPER empty, and you kill the car, as soon as ya restart it the gauge will show full. So he says I need a new cluster. He doesn't even think my car has even ran hot. He thinks its all the cluster. But he mentioned something about miles. How a different cluster will have different miles. Not sure how that works, or even if that could solve the problem. Any input would be great

06-28-08, 04:36 PM
dealer only
there are 13 different resister possibilities and you must get the correct one for your car or else it wont start
and mileage is stored in the cluster and pcm they must match unless you want a mileage tamper on your title which youll never be able to sell the car...

06-28-08, 05:12 PM
Well you seem to be highly intelligent STS2003, can you maybe help me? What could be making my temp gauge appear hot, but really its not, and make my gas gauge appear full ONLY when its down to prolly the last gallon of gas. Maybe AIM or some kind of messenger if you have the time to spare.

06-28-08, 05:54 PM
If the car is running cool and your gauge is lying its the temperature sensor.

06-28-08, 06:19 PM
I thought about that. What if its NOT the Cluster, its a bad temp sensor and a bad fuel sensor. But the fuel thing I can live with, since it has only happened twice and it only happens when theres like NO gas in the car. Any other time its fine. Whats the temp sensor with labor gonna run if you know

06-28-08, 07:53 PM
I thought about that. What if its NOT the Cluster, its a bad temp sensor and a bad fuel sensor. But the fuel thing I can live with, since it has only happened twice and it only happens when theres like NO gas in the car. Any other time its fine. Whats the temp sensor with labor gonna run if you know

At my dealer than is an '02 Eldorado that does the exact same thing with the gas gauge. I think they are ordering a new cluster or sending the old one in to get fixed. From what they told me, it was pretty expensive.

06-28-08, 09:00 PM
The temp sensor, can I do that? Or is it one of those damn jobs that require tools and stuff I dont have. Also about what would that run? For the part and labor if I cant

06-28-08, 09:28 PM
The coolant temperature sensor is maybe $8. Labor is less than an hour @ $80. Fuel tank sensors, changes, and recalls have been in and out of here for years. Keep the tank above 1/4. Period.

You can change the temp sensor if you're willing to get dirty. 6" down and under the right of the throttlebody. PITA.

In your first post: water crossover gaskets. Common source of leaks. Unholy bitch to do. Temp sensor in crossover. Bite the $850 bullet and have the dealer/shop do it all. Then you have someone to fall back on..........

Can't you program your DIC to display coolant temps ?? '97 ?

06-28-08, 09:38 PM
Im not sure about the Display, I haven't really played with it. Im just not sold on the whole cluster replace thing. If my car isn't overheating, then replace the sensor and if I am wrong im out 90 bucks? Makes more sense to me. What he did today was change the coolant, and it hasn't leaked hardly at all yet. Again, the first shop is the one that advised me about the temp sensor and replacing all the gaskets and Crossover stuff. But they wanted 1100 bucks to do it. Did seem kinda high. But I dont know anything about tweaking or programming my Display

Mark C
06-28-08, 11:30 PM
96-02 Eldorado, ETC, ESC
96-97 Seville, STS, SLS
96-99 Deville, Concourse, DeElegance

1) Press the OFF and PASS WARMER (referred to from here as WARMER) buttons simultaneously to enter diagnostic mode.

2) Let the system read any codes it has stored. You will ultimately be presented with "PCM?". You will answer with the fan speed control button. UP = yes and DOWN = no.

3) Press DOWN until you are presented with "IPC?". On mine, it's the very next prompt. When you get to the "IPC?" prompt, press UP to enter the IPC area (Instrument Panel Cluster).

4) Press DOWN until you are presented with "IPC OVERRIDE?". Press UP to enter the override area.

5) Scroll down (with the DOWN button) until you get to Option E. Wait a second or two, and the override value will appear to the right where the TRIP ODOMETER normally reads. Yours will probably read "43". That's what mine read when I first did this.

Below are the Option E values:

- Coolant Temp message (64)
- Battery Volts message (32)
- Engine RPM message (16)
- Avg Mph message (8)
- Mph message (4)
- Fuel Used message (2)
- Inst Mpg message (1)

The stock displays (for analog E/K displays) are Battery Volts, Avg Mph, Fuel Used, and Inst Mpg, for a total value of "43".

6) Use the WARMER button to increment the value of the override. In this case, we want to add Coolant Temp, so we're going to add "64" to "43", or "107". Press the WARMER button repeatedly to increment the value from "43" to "107".

If you make a mistake, you can decrement the value by pressing the COOLER button.

7) To permanently save the new value, hold the FRONT DEFROST and the A/C buttons simultaneously until the new override value flashes once.

8) You're done. Press OFF repeatedly to "back out" of the diagnostic system. You'll probably need to press OFF 5 or 6 times to get out of the deep "menu structure" you're in now.

Now, the coolant temp (in units specified) should be one "stop" along the revolving door we call the DIC. If you are in metric units, the coolant temp will read in *C. If you are in standard units, it'll read in *F.

This will get you the temperture displayed under your tach and speedometer, but it comes from the same sensor that drives the analog gauge on the dash so if your sensor is bad the reading here will jump around, just like your gauge is doing.

Your gas gauge problem is a problem with the sender in the tank. Its a 20 dollar part, BUT the tank has to come out to get at the fuel pump with the sender on it so its a major undertaking. Probably best just to keep your tank level above 1/4 and reset your gallons used display to zero on every tank fillup.

06-29-08, 05:53 PM
Yeah thanks so much, will do that Monday. I think Im going to just tell them to put in a new temp sensor, leave the gas problem alone and go from there. Since its not overheating Ill just replace that and then drive the car for a while. BTW, what the hell does WOT mean :|

06-29-08, 06:41 PM
WOT = Wide Open Throttle.

06-30-08, 11:42 AM
Talked to the Mechanic, still thinks its a bad cluster, but he will do what I tell him, but I havea question. Can a bad cluster only mess with my temp gauge? It wouldn't mess with my RPMs or Speedometer or anything like that? I just find it hard to believe that the cluster is bad when A)I dont think the gas gauge problem is actually a problem with the cluster, so that only leaves the wrong Temp Gauge. I can't fathom a wrong cluster only affecting one point of it. Seems more logical that it would be the Temp Sensor. But if I'm wrong, I'm out 150 bucks. Hrmmm....Decisions...

Mark C
06-30-08, 12:43 PM
I don't know how senders can go bad like you described, they are just varisters that vary resistance thru themselves due to temperature changes. They obviously will fail, but they usually fail open or closed causing the dash gauge to indicate either full cold, or full hot. A signal from a device like a varistor (fuel tank sender is actually a potentiometer and it has moving parts that wear out) that jumps around randomly is much more likely to be a wiring problem (loose connection, chafed wires, etc) than a bad sensor. Don't know what the failure rate of the dash cluster is as opposed to anything else in the circuit.

If you were mechanically (electrically) inclined you could buy a potentiometer disconnect the temperature sender and place the pot into the circuit in its place, set the resistance of the pot to equal some standard reading on your dash and drive around for a while. If the guage continues to bounce around, you know its not the sender, and the problem is either in the wiring or the dash itself. Probably cost you about 5 bucks for a pot and a couple of 6" wire leads.

07-02-08, 11:10 PM
Well got my final update, and boy did the mechanic **** me over HUGE. Called me yesterday said Yep bad cluster. CPU board is fried or some crap. Cost...1600 bucks.. and 2 weeks without my car. I say no thank you. First off is that even possible? Everything works fine on it, except the fuel gauge but thats cause of the bad sendor. I thought if the CPU board was fried the thing wouldn't work. Not sure. Anyways thats that, go to pick up the car, and I be a sumbitch if I dont have deep scratches on my trunk. :| Gunk on my left tire guard, and black gunk on my left mirror. Get inside and the cover that goes over the dash where the Headlamps suggested sensor is is gone. In my back seat, so they put it on and I notice my damn sensors are gone :| Told me to leave the car they would fix the scratches on the trunk and find my sensors, says they must be inside the dash somewhere :| I brought the car home tonight I am seriously scared to leave my car there anymore. I 100% think there is nothing wrong with my cluster. I think at the most its a temp sensor. I think 1600 bucks was outrageously high. And I think they treated my car like it was a pile of junk. ive taken photos and Im going to upload them tomorrow, but im at a loss of words

Do I risk them fixing it, but potentially screwing something inside my car up? Other than that, car ran fine. Not hot, I even did the WOT thing like somebody told me to do. Ive just never been so damn mad in all my life. I would NEVER do that to another persons vehicle. I durno. Anyways I still think 1600 bucks to repair a Cluster is way too much when the dealership and the auto shop they outsource too said like 350-500 Max...

07-03-08, 06:23 AM
Here's another thread on cluster replacement for comparison:

As for your mechanic - do not have them fix it, get the car back and never go there again. Sounds like they know jack about Cadillac and would be happy to take your cash.

07-03-08, 09:01 AM
There was a thread or two some time ago concerning light sensors - it seems they are not really tight in their snap mounts and tend to fall down in the dash. You have some fishing to do.

Personally, I would stay away from whoever this mechanic/shop is........

07-03-08, 09:38 AM
On most Cads the twilight sensor is straight in front of the driver pointing up. If there are two domes sticking up on either side of the defrost vent those are sun-load sensors for the climate control.

Mark C
07-03-08, 11:55 AM
A new IPC on Ebay is about 50 bucks, You might need to get it reprogrammed for your mileage and possibly your anti theft transponders, but that will only cost you 250 bucks or so, it might even be plug and play (except for mileage). Might take 2 to 3 hours for a rookie to replace, 1600 bucks is a huge ripoff.