JBLODER Posted August 15, 2005 Report Share Posted August 15, 2005 HELLO, I HAVE A 92 ELDORADO WITH 4.9 ENGINE, EVERYTHING SEEMS TO WORK FINE WITH CAR EXCEPT THAT WHEN I AM IN TRAFFIC WITH AC ON THE CAR WILL OVERHEAT. WHEN IT STARTS TO OVERHEAT I HAVE TO TURN OFF THE AC AND THE CAR WILL COOL HERSELF DOWN WHILE STILL BEING IN TRAFFIC. COOLENT IS GOOD MIX AND ONLY 3 MONTHS OLD FANS SEEM TO RUN FINE, WITH CAR IN DRIVEWAY THEY CYCLE BETWEEN ABOUT 200-223 DEGREES. WITH AC ON THEY RUN ALL THE TIME. ANY HELP ANYBODY CAN OFFER WILL BE GREATLY APRESHATED JOEL Link to comment Share on other sites More sharing options...
Scotty Posted August 15, 2005 Report Share Posted August 15, 2005 Please explain what you mean by overheat. What temp does it go up to. In hot summer heat it should be OK at 235 degrees, even 240. In 95+ degree heat with my 91 (same engine), I would see 240 in traffic, but that is about as high as you want to go If your coolant mix is ok (50/50) and she is spitting coolant try changing the radiator cap, MAKE SURE its the correct type. The correct cap has a poppet valve in it that allows coolant to come in from the resouvior as the engine cools. Make sure you are filling the system correct. Fill the radiator to the top, fill the resouvior to the cold line, start the car let it run up to 220, then turn it off and let it cool, top off the resouvior again to the cold line, and drive it. Again 50/50 using distilled water. It is by design that the fans run with the AC is on. Make sure they run STRONG I had a fan in my 91 that was not running strong as it was burned out.. Clean all debris out of the radiator and condenser fins, if you have NOT changed your thermostat do so, eliminate that potential problem, maybe its not opening all the way If all else fails pressure test your cooling system to make sure it holds 16 PSI, the side tanks on the radiator are plastic and they can leak. DON'T FORGET to use the cooling supplement, do a search for it, use 6 tablets if you never used it, you will see a warning on your shock tower I believe. Here is a photo of the package Link to comment Share on other sites More sharing options...
Scotty Posted August 15, 2005 Report Share Posted August 15, 2005 One more thing, I hate to bring up internet etiquette, but typing in ALL CAPS is akin to SHOUTING. Link to comment Share on other sites More sharing options...
JBLODER Posted August 15, 2005 Author Report Share Posted August 15, 2005 Sorry have bad habit of not taking caps off ofter writing worksheets for students, will try to do better. Temp. of car keeps rising, usually by the time it hits 235-240 i will turn off AC, it takes about a minute and 2 degrees after i turn it off until it starts going back down. It has gone as high as 245 when I wasn't paying attention. The only time that i loose any coolent seems to be when i let it get too hot and turn off car, it will boil out of overflow tank. The fans seem to run fine, as far as i can tell, if needed i can replace them both but it seems more like something is keeping them from running full speed when AC is on. I can be sitting in same traffic jam and turn off AC and car will cool down fine and keep tempature between 205 and 225. I dont have any of the tablets in system, I will pick some up tomarrow and put them in. thank you for your help Joel Link to comment Share on other sites More sharing options...
adallak Posted August 15, 2005 Report Share Posted August 15, 2005 A proper mix would not boil at 245. I would just spare 13 years old car and turn the AC off. Remember you have a lot of old stuff under the hood which can go bad with that high tepms (connectors, sensors, wires, etc). My ABS started acting up then the temp. got 210... go figure. I would just sacrifice the comfort to avoid much bigger possible issues. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
JBLODER Posted August 15, 2005 Author Report Share Posted August 15, 2005 Perhaps that is part of problem. Then Temp. increases 10-15 degrees after I turn off car. Link to comment Share on other sites More sharing options...
adallak Posted August 15, 2005 Report Share Posted August 15, 2005 Perhaps that is part of problem. Then Temp. increases 10-15 degrees after I turn off car. Yep, when you stop the flow, local volumes of the coolant can still get wormer and eventually boil. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
JBLODER Posted August 15, 2005 Author Report Share Posted August 15, 2005 SUMMER WITHOUT AC, I WOULD RATHER BUY A HONDA!! Link to comment Share on other sites More sharing options...
TDK Posted August 15, 2005 Report Share Posted August 15, 2005 JBLODER, How long have you had the car? Has the A/C ever worked OK? If yes, then under what conditions? Aside from hot weather, where any other vehicle changes - like engine work? I reall one post had an really odd problem with a 4.9 A/C fan control. It turned the fans backwards!! This was not as noticeable as you think. The A/C was OK until the car was in traffic, other wise the air flow through the grill at speed overcame the backasswards fans! Good luck Add power to leave problems behind. Most braking is just - poor planning. Link to comment Share on other sites More sharing options...
Scotty Posted August 15, 2005 Report Share Posted August 15, 2005 Sorry have bad habit of not taking caps off ofter writing worksheets for students, will try to do better. Temp. of car keeps rising, usually by the time it hits 235-240 i will turn off AC, it takes about a minute and 2 degrees after i turn it off until it starts going back down. It has gone as high as 245 when I wasn't paying attention. The only time that i loose any coolent seems to be when i let it get too hot and turn off car, it will boil out of overflow tank. The fans seem to run fine, as far as i can tell, if needed i can replace them both but it seems more like something is keeping them from running full speed when AC is on. I can be sitting in same traffic jam and turn off AC and car will cool down fine and keep tempature between 205 and 225. I dont have any of the tablets in system, I will pick some up tomarrow and put them in. thank you for your help Joel No problem, ok first as Adallak said, if she is boiling you don't have a 50/50 mix, 50/50 should take you up to 260 or 265 degrees before it boils, UNLESS your system is not holding at least 15 PSI it will boil at a lower temp. EIther have your coolant checked or buy a checker and check it, they are cheap. Adjust your coolant till its 50/50. Change your radiator cap and thermostat and try it again.. The weather has been hot, so you have to expect your car will run hotter, just make sure your hoses are good and that she is capable of holding 15 PSI, if not find the pressure leak and fix it, and you will be fine. The fans should run at high speed you may need to diagnose them, there could be a bad relay, there are three relays, do you have a factory service manual? Believe it or not the car SHOULD run cooler with the AC on because the fans run at high speed, before I fixed my AC my temps would cycle and down more reacting to the fan cycling on at 226/228... With the fans running on HIGH with the AC on, the temps are more stable.. The temps increasing after you shut the car off is normal, mine read 240 degrees the other day after I turned it off Link to comment Share on other sites More sharing options...
bigjayzway Posted August 15, 2005 Report Share Posted August 15, 2005 SUMMER WITHOUT AC, I WOULD RATHER BUY A HONDA!! Slowly take your prominant hand, and slap yourself in the back of the head! I too have an older 4.9 in my Deville. The coolant doesn't boil, but does get up there in temps.(about 225-235) when it is really hot out. It sound like you need to change the thermostat(easy job) becuse it is not functioning properly. Don't think you need to shut it off, no matter how old it is! Change the fluid, and the thermostat, add the tablets, and you will see the problem will be fixed! I would just spare 13 years old car and turn the AC off. Remember you have a lot of old stuff under the hood which can go bad with that high tepms (connectors, sensors, wires, etc). adallak, rubber gets dry and brittle over years, but a couple of bucks will replace these, and you can get them almost anywhere. Thats like saying "your leather is getting old, so don't sit on it"....No you condition it, and enjoy!. Same as the rubber, replace or lube them, and it will be fine. Big Jay Life is too short to grow up! Link to comment Share on other sites More sharing options...
Scotty Posted August 15, 2005 Report Share Posted August 15, 2005 Not being critical Adallak, but my mother in law and wife have this approach to life. There attitude is that AT MY AGE I should not go to the gym to work out as I will hurt my joints and in their words, I AM TRYING TO BE 18 AGAIN...how negative could you be?.. To make matters worse my mother in law was a full time nurse for 20 years and not NOW she can't open a jar or pick up a case of water and wonders why! DUH you do nothing to maintain your muscle tone, thats why! Pretty obvious to me! But she will be quick to criticize me for making the effort, amazingly stupid. I think that is an assinine approach to life, I tell them to CLIMB in your CASKET and be done with it.... Neither one of them can run a block! Its a fatalistic approach to life. In their case they are LAZY..... Staying in shape is HARD WORK, most people make excuses and criticize it... seeing someone else do it makes them feel inadequate and lazy..but they don't see that... Me, I HATE being out of shape and NOTHING and NO ONE will change that, it comes from playing basketball through college and having always been in good shape since I was a kid.. It tends to be easy for me to return to 90% of that level, the other 10%, IS NOT EASY.... I don't like fatalistic, negative, safe belt and suspenders people. Good things and good results take lots of effort. Again this is not directed at you Adallak, Big Jay got me going.... The car is old so don't use the AC is a similar slant on this... Link to comment Share on other sites More sharing options...
adallak Posted August 15, 2005 Report Share Posted August 15, 2005 Not being critical Adallak, but my mother in law and wife have this approach to life. There attitude is that AT MY AGE I should not go to the gym to work out as I will hurt my joints and in their words, I AM TRYING TO BE 18 AGAIN...how negative could you be?.. To make matters worse my mother in law was a full time nurse for 20 years and not NOW she can't open a jar or pick up a case of water and wonders why! DUH you do nothing to maintain your muscle tone, thats why! Pretty obvious to me! But she will be quick to criticize me for making the effort, amazingly stupid. I think that is an assinine approach to life, I tell them to CLIMB in your CASKET and be done with it.... Neither one of them can run a block! Its a fatalistic approach to life. In their case they are LAZY..... Staying in shape is HARD WORK, most people make excuses and criticize it... seeing someone else do it makes them feel inadequate and lazy..but they don't see that... Me, I HATE being out of shape and NOTHING and NO ONE will change that, it comes from playing basketball through college and having always been in good shape since I was a kid.. It tends to be easy for me to return to 90% of that level, the other 10%, IS NOT EASY.... I don't like fatalistic, negative, safe belt and suspenders people. Good things and good results take lots of effort. Again this is not directed at you Adallak, Big Jay got me going.... The car is old so don't use the AC is a similar slant on this... Scotty, I 100% agree with you - I am VERY hard on myself. In my 46 I climb mountains just like I did 20 years ago, hike at least three times a week for 4-5 hours and never choose an easy terrain. My car is a different story though. It changed me in five years so drastically. I used to be a perfectionist with respect to things which belonged to me...I just see all the time people spending literally thousands and plenty of their time on their cars right before they go to junkyard anyway...But you know looks like I am changing... Every time I fix something I did not care about for 3-5 years I think heck why I did not do that 5 years ago!!! JBLODER, fix your cooling system and enjoy the rest of this cool summer! The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
CDRSAVAGE Posted August 16, 2005 Report Share Posted August 16, 2005 My 94 DeVille did that and it turned out to be a blocked radiator, only the top to tubes were working. you can verify this by starting the care up cold and when you feel hot water in the top radiator hose, place your hand on the front of the radiator and feel for heat from top to bottom and the car warns up if you never get good heat in the lower coils, just change it. I have yet to see a modern radiator worth repairing as they are made from practically nothing and that is whats left in about 5 years............luck P.S. Someone told me there was an outfit in CA that sells any radiator cheap. He said he bought one for $40.00 dollaras for a ford truck. Search the net........luck Link to comment Share on other sites More sharing options...
KevinW Posted August 16, 2005 Report Share Posted August 16, 2005 Verify that the cooling fans run at both low and high speeds. In the first stage, the fans are run in series (half voltage); high works via a relay that connects them in parallel. It is possible the high speed relay or associated wiring is defective. Modern radiator cores last far longer than the older copper/brass equivalent; only the tanks need periodic (10-15 years) replacement. Recently, I replaced a radiator tank on a 1991 STS for a coolant seepage issue (the gasket around the oil cooler inlet had deteriorated). The core was 100% clear, and there was no noticeable fin corrosion. ___________________________________________________ Link to comment Share on other sites More sharing options...
adallak Posted August 16, 2005 Report Share Posted August 16, 2005 Verify that the cooling fans run at both low and high speeds. In the first stage, the fans are run in series (half voltage); high works via a relay that connects them in parallel. It is possible the high speed relay or associated wiring is defective. Modern radiator cores last far longer than the older copper/brass equivalent; only the tanks need periodic (10-15 years) replacement. Recently, I replaced a radiator tank on a 1991 STS for a coolant seepage issue (the gasket around the oil cooler inlet had deteriorated). The core was 100% clear, and there was no noticeable fin corrosion. Last summer I replaced the both (plastic) tanks because of craks and the core was fine. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
jfreezn Posted August 17, 2005 Report Share Posted August 17, 2005 The radiator cap and thermostat should be replaced as a matter of maintenance every few years. A leaking radiator cap is often undetectable as small quanitities of vapor slip away until there is a shortage of coolant, then you get noticable overheating. I found that dirt that accumulates on the front of the radiator cannot be removed by any safe cleaning method while the radiator is installed. You have to remove the radiator and flush the fins clean. You cannot see this trash, which is behind the AC condenser. I have found large accumulations on both my 94 ETC, my 79 300SD, and my daughter's 95 Mustang. If your car has gone down the road 75 to a 100 thousand miles without removing the radiator, it is time! NOTE: Most radiator services, done by a shop, will never tell you about the external dirt found, you are paying for a rodding out or boiling out and who really knows which had the biggest benefit, cleaning the inside or the outside of the radiator. Apart from that, the plastic end tanks will crack and are very difficult to spot. Coolant will may not even hit the ground, initially. By the way, 1-800-RADIATOR provide OEM quality replacement radiators, delivered to your door in hours, and less than $200 for the biggest models. Good luck, Jim in Phoenix Jim in Phoenix Link to comment Share on other sites More sharing options...
Scotty Posted August 17, 2005 Report Share Posted August 17, 2005 Good advice Jim! Being that you are located in Phoenix (my favorite place but located 1/2 mile from the SUN), your advice is valuable! Thanks Link to comment Share on other sites More sharing options...
adallak Posted August 17, 2005 Report Share Posted August 17, 2005 A leaking radiator cap is often undetectable as small quanitities of vapor slip away until there is a shortage of coolant, then you get noticable overheating. Is not the cap designed to "leak vapor"? Where and how does a bad cap leak vapor? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted August 17, 2005 Report Share Posted August 17, 2005 The cap should leak nothing below what it is designed in terms of pressure, if it is suppose to hold 16 PSI, nothing should pass as long as the pressure is below 16 PSI, if the pressure is above 16 PSI, it will relieve, but that is rare unless the system boils due to less than a 50/50 mix The problem occurs when the cap is relieving below 16 PSI, say, 9 PSI because the pressure spring or seals are worn or defective or dirt clogs the poppet valve. Then you will leak coolant and she will boil at a lower temp due to the decreased pressure. I have begun replacing me cap every few years, it is overlooked easily. Link to comment Share on other sites More sharing options...
adallak Posted August 17, 2005 Report Share Posted August 17, 2005 The cap should leak nothing below what it is designed in terms of pressure, if it is suppose to hold 16 PSI, nothing should pass as long as the pressure is below 16 PSI, if the pressure is above 16 PSI, it will relieve, but that is rare unless the system boils due to less than a 50/50 mix The problem occurs when the cap is relieving below 16 PSI, say, 9 PSI because the pressure spring or seals are worn or defective or dirt clogs the poppet valve. Then you will leak coolant and she will boil at a lower temp due to the decreased pressure. I have begun replacing me cap every few years, it is overlooked easily. So "leaking vapor" means actually not holding the designed pressure? In this case as you mentioned the coolant may boil at say, 240 degrees and escape through the surge tank cap (in my case). This is something you really cannot overlook. I do not see how you can loose significant volumes of coolant by just "leaking vapor". The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted August 17, 2005 Report Share Posted August 17, 2005 I do not believe it would leak anything. No vapor should be in the radiator at all. If pressure exceeds the caps rated pressure it will leak coolant. Air is normally purged out. Maybe I am not sure what you mean by vapor, to me vapor mean steam, and STEAM is something you do not want in your cooling system as it results from boiling. AIR is expelled in the normal heating and cooling cycle as the system pulls in coolant (on your car) as is cools.. Link to comment Share on other sites More sharing options...
adallak Posted August 17, 2005 Report Share Posted August 17, 2005 Scotty, Vapor presents always if you have a liquid (and even solid state). Steam is ... a lot of vapor. Perhaps, the author of the original statement will explain to us what he means saying "vapor leak". The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted August 17, 2005 Report Share Posted August 17, 2005 "vapor slip away until there is a shortage of coolant" I think he is saying that its spraying under high pressure not unlike the fine spray on a garden hose at hot temps and as a result of the hot temps and radiator heat its immediatly vaporized, I have seen this, steam appearing to seep where the ribs meet the side tank area. I don't think he is saying there is vapor in the radiator. Link to comment Share on other sites More sharing options...
adallak Posted August 17, 2005 Report Share Posted August 17, 2005 Yeah, physics does not tolerate liberal definitions... The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
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