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'92 STS still overheats...argh...


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1992 4.9L, 146k miles, new everything, radiator, heater core, all hoses, pump, thermostat, etc... I do have an intermittent PCM problem, where some of the digital readout blank out with --- instead of actual numbers. The defroster kicks on in A/C mode, temp ind. blanks out, and hitting the "off" button doesn't work until the computer comes back on line. So I cannot really tell how hot it is, around 212 to 235. Drove it today 20 miles, when I got back it was spitting coolant down the driveway. Radiator was FULL when I left this morning, and it has been burped. New water pump was the last item installed, and I used the "Bars Leak" GM fix also. It acts like a head gacket, but runs cool and fine for 20 miles or so, but seems when it does get hot, due to traffic, or stop and go, it cannot cool down. Fans are working ok, and kick in at 235 I believe...other than acting like a head gasket or similar, it has NO coolant in the oil, no water out the tail pipe, or similar. Runs smooth, hits on all 8. It does get a little pre-ignition when hot...I am at my wits end. Getting ready to scrap the whole car. It is the nice White Pearl, with Sunroof, and Bose Gold Stereo. If the plugs on the rear bank weren't so hard to pull I would pull a compression test or so. Can a Head or Head Gasket if ruptured, stay closed and not affect the engine, until it gets hot?? If so, that's probably it, unless the PCM is causing the overheating... I went through the codes earlier today, looks like an intermittent connection type codes only...any help would be appreciated, Thanks Guys.

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It seems like a few different problems are happening here but you don't mention if you recently installed a new radiator cap.

I have a 92 SLS which also has the 4.9 engine and my fans kick on at 223F while its "normal" operating temperature seems to range around 203 to 212, which is why I'm wondering about the radiator cap or even the thermostat now that I think of it. (Maybe these were included in your reference to "etc." in which case I apologize for asking about them).

Are you seeing any steam or heavy smoke from the exhaust pipe other than the normal condensation of a cold morning?

If you got codes, please post them.

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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3 Radiator caps, 3 thermostats, even ran it without a thermostat for awhile...

No Steam, no real indication of head leak or similar, darn thing just gets hot...enough to boil over. I just checked it now, coolant level is way down, overflow tank is virtually empty.

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3 Radiator caps, 3 thermostats, even ran it without a thermostat for awhile...

I apologize but I edited my message apparently while you were posting yours.

If you have codes, please post them.

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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I hate to say it but I believe you have a blown head gasket. When a head gasket blowes it doesn't always leak coolant into the oil or the coolant doesn't leak into the exhaust causing antifreeze to come out the tail pipe. I have had this happen to me too. I was confused also, but it turned out that I did have a blown head gasket and I had the same symptoms you are having now. What happend is the head gasket is blew between the cylinder and a water jacket. The water jacket is what allows the coolant to flow through the head and cool the engine. In your case since where it's blown its causing compression from the cylinder to enter the cooling system little by little until the radiator cap can't hold the pressure and most of the coolant leaks out of the over flow tank. I know this isn't what you want to hear, but I believe thats what your problem is.

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It makes sense, seems to be really hot scalding water when it starts coming thru the radiaror opening if I have the cap off checking it. I guess I am just used to seeing coolant in the oil or water out the tail pipe on other cars that have had a combustion chamber issue. I think you are right, just wanted to look at evrything else :( first...

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Here are the codes;

E047, E052, IO33,34,37,39,52, A037, R051, R061....

P047 (E047) ............................ IPC - PCM Data Problem

P052 (E052) ............................ PCM Memory Reset

I033 ....................................... Loss of Supplemental Inflatable Restraint Data

I034 ....................................... Loss of Powertrain Control Module Data

I037 ....................................... Loss of Air Conditioning Programmer Data

I039 ....................................... Loss of Road Sensing Suspension Data

I052 ....................................... Keep Alive Memory Error

A037 ....................................... Loss of Instrument Panel Cluster Data

R051 ...................................... Frontal Crash Detected

R061 ...................................... SIR Indicator Circuit Failure

Almost sounds like your battery went dead or something.

Try clearing the codes and restarting the car then post the codes.

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Here are the codes;

E047, E052, IO33,34,37,39,52, A037, R051, R061....

E047 = IPC-PCM Data Problem

E052 = PCM Memory Reset

I033 = Loss of SIR Data Communication

I034 = Loss of PCM Data Communication

I037 = Loss of ACP Data Communication

I039 = CCR System Problem

I052 = IPC Loss of Memory

A037 = Loss of IPC Data

R051 = Accident Detected

R061 = Force Low or "INFL REST" warning map circuit failure

Hope these help.

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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Yea, it really sucks when it comes down to that. If I was you I would fix it myself to keep away from the dealers HIGH labor rate. parts really shouldn't been to awful high, its usually the labor that gets ya. Its a long process, but its not that hard, if anything just aggrevating. Good luck.

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3 Radiator caps, 3 thermostats, even ran it without a thermostat for awhile...

No Steam, no real indication of head leak or similar, darn thing just gets hot...enough to boil over. I just checked it now, coolant level is way down, overflow tank is virtually empty.

Did you open the radiator cap and look down into the radiator and notice if the fluid is circulating while the engine is running?

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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I'll see if I can clear the codes and re-group, but I tend to agree with CaddyDaddy, it's prob the head issue.... and yes it did replace the battery as well. The intermittent computer prob has something to do with the error codes as well...thanks for the code info! Boy when the computer makes the temp display go to dashed lines --- it's hard to tell what temp it is at. Before I replaced the waterpump, and radiator I saw it go to 252 at a stoplight...so it is probably the same. I think I'll start preparing to get the head work done. Then have to find the pesky intermittent computer connection...my Hayes manual isn't really clear on where the computer (s) are located...

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Dont know on the head gasket issue. 4.9L engine. Huh...mine went 202K fine before I sold it.

I do know about your other problem. The 'loss of data' codes.

First if the PO52 is showing up repeatally. Check the battery cables for corrosion inside the cable at the battery. Common GM problem.

All the computers are connected on a UART data line. All the computers 'talk' to each other on the tan circuit 800. Circuit 800 is wired in a loop...so the signal is bidirectional. This greatly reduces the chances of a wiring issue causing the codes.

If one of the computers goes bad. It can corrupt the data signal on circuit 800. And you will see the pattern.....display goes '--' on the IPC, then the AC goes into defrost, mega warning messages start displaying. etc.... Sound familiar?

Also clean the front engine ground on the engine block near the starter. Common problem. GM has a TSB on it.

If the battery cables and grond are ok. It would sound like one of the computers has gone bad. Plus the problem is almost always intermittant. Yeah!!!

The bad computer could be one of these....

PCM- powertrain control module (called ECM in '92)

IPC- cluster

RSS- road sensing

DERM- airbag module

ACP- a/c controller

ABS- anti lock

Now.....finding the bad one can be a *smurf*. If your lucky you can catch it. You messure pin M on the ALDL. You should see 3.0v - about 4.2v AND flucuating all the time. When the problem happens.....the voltage will either freeze at say .5v or high at 4.4v kind of thing. You can often 'see' the problem with a DVOM about 15 seconds before the cluster will mess up.

On my '93 SLS the problem was a bad IPC cluster. The problem was intermittant about every 100-500 miles. A rebuilt IPC are available from Delco radio/speeometer repair shops for $300 exchange.

Please be aware. It appears the GM Delco cluster diagnostic terminal is unable to detect internal circuit 800 failures in the IPC. When testing the cluster. A normal test mode IS '--' in the data display. So...in some cases....its taking 3-4 new IPC clusters to fix the problem.

Have fun....these are a *smurf*.

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Hey, read on page 3 "overheating problem 92 eldorado" there are alot of great ideas.

Jim

http://www.geocities.com/girlperson2/

Go to the above site. If the link doesn't work, COPY and PASTE it into your browser.

Scroll down a bit and click the link for COOLING AND RADIATOR. You will need Adobe Acrobat Reader to view the document. I scanned the entire chapter from the '92 Seville/Eldorado Service Manual.

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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Let me add my two-cents. Please make sure that you have the correct radiator cap, the cap for the 4.9, had a poppet valve in the center that faces the coolant that you can pull down gently with your fingers, if you have the wrong cap, you will not be able to pull coolant from the reservoir and your system will not purge the air out and you will overheat as the system will not stabilize.

Secondly, make sure that you fill the system properly, filling the system improperly will not completely fill the radiator, that combined with a less than 50/50 mix will boil. I fill my 4.9 by filling the radiator, leave the cap off or loose, and allowing the car to warm up to about 195 so the thermostat opens and the coolant circulates into the engine, you will see the coolant drop, be carefull that you do not allow it to get too hot so that it spits coolant out as soon as the thermo opens shut the engine down. Be careful, coolant less than a 50/50 mix can spontaineously explode/boiling. Top off the radiator, tighten the cap, fill the reservoir to the hot line and restart engine allow to warm up fully and then shut it off to fully cool....it will suck coolant in AS IT COOLS.

Third, make sure you have a 50/50 mix of coolant, otherwise you are boiling it out, buy a coolant tester and check it. Its also possible that your PCM problem is retarding your engine causing it to over heat (just a stab in the dark, but i doubt it). Also, check your LOWER radiator hose to see if it is collapsing when you rev the engine up. The replacment hoses come with out the spring if the hose gets soft I have seen them suck closed and starve the radiator of coolant. Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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  • 1 month later...

Looks like it is fixed now! Runs 170-185 on a cool morning, 196-205 normal highway, and 235 or less in stop and go. Apparantly I had the overflow bottle too full, and it would boil over and spit out, when doing the normal expansion. I adjusted the level, and seems to be ok. Thanks guys....!!!

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Here are the codes;

E047, E052, IO33,34,37,39,52, A037, R051, R061....

Well here are the latest codes,

IO 33

IO 34

IO 37

NO ACP

NO SIR

NO ECM

IPC DATA

Apparantly 2 guys on the board here had identical problems with the defroster, one was a bad IPC, the other a bad PCM, (why can't this be simple), anyway, just want to pick the experts brains here once again, I found this place on the Web

http://www.mrwhizard.com/index.cfm for IPC repairs. He indicated that usually the components are ok, just the solder connections are bad...anybody out there try to fix theirs? Apparantly Surface Mount Technology (SMT) I work in an Aerospace Electronic Circuit Card Manufacturer, and that's all they do here. I may try to reflow some solder myself. Anybody pulled their IPC out on a '92-95 Eldorado or Seville, I believe these years have the same IPC? Thanks in advance for all of your help!

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