Prop_Washer2 Posted June 5, 2004 Report Share Posted June 5, 2004 I just borrowed a cooling system pressure tester from a mechanic friend, I have pumped it up to 16 lbs., I see a few drips underneath the car, behind the front crossmember, perhaps 1 drop every 15 seconds. Is there anything else I need to know on doing this pressure check. I suspect I am loosing coolant somewhere while driving... Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 5, 2004 Author Report Share Posted June 5, 2004 OK got under there, looks like it is dripping from the rear area of the AC compressor , argh...is there a cooling system interface on the AC compressor??? 4.9 Liter, old school V-8, 146K miles... Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 5, 2004 Author Report Share Posted June 5, 2004 Hi Guru, I ran the system up to 20 psi, it holds real well. I pressure checked the cap, it breaks into vent mode at about 15 psi. I went and bought a new Stant Lever Model 16 psi, put it on road tested it and it was worse, she is running hotter. I came back home, put the tester on it, it breaks at about 13-14 psi. I exchanged it for another one, I tested it, it breaks at about 13-14 psi as well. So I put the pressure guage on the radiator, after topping off the coolant, and ran the engine to see what kind of pressure are we dealing with. The fans kick on at 232, and kick off at 205-207. The pressure low is 6 psi, goes up to 11 psi, when the fans kick on, and bring the temp down. Now, I decided to run it up say about 3500 to 4000 rpm for 4-5 minutes, holding the throttle arm, while watching the pressure guage, it took awhile but went to 17-18 psi, temp was 234, fans just kicked in. It appears the the cap needs to be rated higher than the standard 16 psi, and all of them I pull off the shelf (Stant Lever Types) break pressure at 15 or lessm and appear to hold pressure at 11-12 psi. She really boils off into the coolant tank when at 220 degrees or better... I see High Pergormance caps from Moroso and a few others up to 25 psi, but I really feel if the darn cap would hold, she would be allright...Guru your the expert... Also does the coolant overflow tank need to hold 16 psi as well, it just fills up and flows out the top... Link to comment Share on other sites More sharing options...
Dan Posted June 6, 2004 Report Share Posted June 6, 2004 You most likely have a leaking water pump. It is the only area where this isn coolant near the ac comp. Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 6, 2004 Author Report Share Posted June 6, 2004 Pretty close to 50/50 on the mix. I usually run 70/30 as this is the maximum boil over protection, and maximum (lowest) freeze point. I agree with the millions of cars out there running standard 14-16 psi systems, and yes the combustion chamber leakage is a possibility. I have an entire new cooling system. Funny, I can take it out and run 100 miles on the freeway and temp stays at around 194-198 a good temp, I hit city traffic and she'll come up to 223-225, get on the road, 65-70 and it will ease back down to the 190's. I just got back from a 50 mile run to test another brand of radiator cap I just installed, a (CST brand), it was 101-102 earlier today same run when it was boiling over when I stopped to check it, now it was 98-100 with the sun down (but it is a dry heat ) anyway same route pulled back in the driveway 223 on the button (Fans run at slow speed kicking on at 223) I turned on the A/C which kicks the fans into high speed, and it cooled down to 219 or so. No boil over at 223 or 219. My mechanic buddy (don't we all have one) thinks the fans should kick in a little earlier like 210 or so...I cannot find anything in the crapy Clymer's book that I have on the temp that they should turn on. I think that if I had a combustion leak, it would not run at 190's on the highway. In the morning at 6:30 am, when it is cool, I drive to work 20 miles or so, and it stays at 185 ish. Idle is smooth, acceleration is smooth. I did place two Bar's leaks little tubes when I originally thought I had a head gasket issue, plus when I installed the new radiator last summer I put a can of Bar's leak in as well. Prob most has boiled out. If the fans are within spec coming on at 223, then I prob should flush the system with a light prestone backflush kit, then refill at 50/50 to 70/30 mix on the coolant. I have read your insistance on the Bar's leak type sealer as per GM recommendations. I'll pop one of the little tubes in as well...I respect your opinion and expertise, but this one is a lttle funny but I am sure it can be resolved. It has gotten a lot better since last summer... doesn't get nearly as hot, bad hoses then...Thanks Guru! Link to comment Share on other sites More sharing options...
Ranger Posted June 6, 2004 Report Share Posted June 6, 2004 Just a thought. Check the radiator fins. May be clogged with bugs and dirt over the years reducing cooling. Flush it out with compressed air and water. Maybe it will help. Link to comment Share on other sites More sharing options...
Poobah Posted June 6, 2004 Report Share Posted June 6, 2004 If you've changed radiator caps and are still having problems, make sure you have the correct, i.e. vented or non-vented, cap for your application. Your parts counter person can check this for you. I got the wrong cap on mine a while back and it kept "boiling over". Once I realized what the problem was and got the correct cap, the problem was solved. Sounds like you might be having the same dilfficulty. Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 6, 2004 Author Report Share Posted June 6, 2004 Thanks guys, all great ideas...the radiator is 4 months old, still real clean, and I'll go with the 50/50 mix on the coolant, now the venting cap could be a problem. I believe, everything I am pulling off the shelf is vented for that model. After it cooled down last evening, she was low on coolant...I started it with the cap off, threw in some AF and water...temp guage said 209 idleing with the cap off, water is flowing good, but as the level was coming uo, I was seeing white foam, just like the head of a good mug of beer. Once I got the foam cleared out, to see the coolant, I am see little bubbles while it is running. I don't mean to sound like a hypochondriac or anything, just trying to pass on what I see to you guys. Looks like she blew off 1/2 gallon or so on the last 50 mile run... I guess we can eliminate the radiator, (new and clean), radiator cap defective (4 diff ones all perform the same), new water pump, 300 miles ago, Vented or Non-vented could be an issue, fans coming on at 223 or so seems ok. Runs cooler with the A/C on as the fans run at a higher speed earlier, as a note, it appears that even below the boiling point of water 212, the coolant still wants to get out of there, and jump into the tank...combustion chamber leak issues, possible, BUT, it is 9:00 in the morning here, I can prob jump in it, drive 100 miles down the I-10, and it will not get over 190-195...I was hopeing this will rule the combustion chamber leak out. It does appear though, (maybe). I have noticed that once it gets hot, that it probably looses coolant, and it exacerbates te problem, THEN it has trouble cooling down. Wasn't there a GM recall on welding a steel plate onto the radiator opening in place of the cap?? I really appreciate the input guys... Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 7, 2004 Author Report Share Posted June 7, 2004 Just got back from a little run say 30 miles one way, went to a water part for 6 hours...used the A/C all the way, it ran at 195-198 for the first 15 miles then wased up to 205 for awhile, then 210 back to 207-208 for the remainder, pulled into the parking lot there it was at 223 with a few blocks of city traffic or so...not bad, came home ran at 195 for awhile, then eased up to 205-210, hit a little traffic close to home, it was 232 when I hit the driveway, all numbers that are workable. I just checked the overflow after sitting 10 minutes turned off, it is full to the brim, temp says 239, no boiling or bubbleing. 232 seems to be the new high now with the A/C running, last summer I saw 250-260, as there was a leak somewhere blowing it out. I'll check later to see if it drains back. (In looking at the neck of the radiator, vs the rubber-gasket seal on the end of the spring that holds pressure, that a positive pressure needs to exist to allow the coolant to come back in. If there is zero pressure in the system, then the seal and maybe always, seals the opening) I guess they work somehow. That could be the issue...concerning the cap, all radiator caps off the shelf, (Stant, CST, etc...) are all configured the same. I topped of the coolant last night, and it will be interesting to check the level when it cools. I know where the levels were last night and in the bottle, as long as they are not boiling off, or blowing out while driving it should be the same today...thanks for the support! Link to comment Share on other sites More sharing options...
Prop_Washer2 Posted June 7, 2004 Author Report Share Posted June 7, 2004 Well I checked last night, the bottle went down, about 3 inches, and I opened the radiator cap, it looked topped off. Ya know, I may have too much coolant in this puppy, as when cool, the bottle is a the "Hot Level", and when Hot it is at the brim, sooo.... I am gonna take a little out via the connecting tube. I am gonna drop it to the levels specified on the bottle... Link to comment Share on other sites More sharing options...
92 deville-loveit Posted June 9, 2004 Report Share Posted June 9, 2004 HI guys ... check out some of my posts 92 deville-loveit on this site and 92deville-loveit on that other site that Mr. Bbobinski supports so well also. I see two things coming to mind ... the coolant temp is 185? To me that sounds like the wrong thermostat I think the factory one is 192 ... saw some stats brand at Walmart here in Connecticut today at $1.77 each I paid aboot $7 on the road and Autozone wanted about $12 for a crummy looking one. Also their's did not include the O-ring gasket. The other think I note is that you were having a low colant level in the radiator ... IF that hose from the overflow tank leaks air the coolant from the radiator only makes a one way trip. HTe connection at the radiator has to be very tight. As for my 100K fight with over heating ... I broke down in Coffee Springs Al miles form anywhere and no touch tone service and no cell phone service and finding a computer to use was a hassle but as My father said that chicken coop /shed became a fine Caddy garage as it kept the hood area of the car out of hte sun and rain. I replaced the head gaskets and I had to rethread the stripped threads in the block when I tried to retorque the new heads to specs on assembly. In all I spent $200 for new head bolts (at least one was somehow factory defective - check them very carefully) and about $300 for everything else. Here in Connecticut I replaced a few formed vacuum lines for $5 each and I am still fighting TPS problems that I brought under control by removing the ICS motor. Today for the first time my closed throttle angle was finally down to 1.3 after another readjustment and the TPS voltage at closed throttle was 0.570 volts still out of specs but tollerable. I am still looking for a magnetic timing light and would travel a hundred miles out of my way to get the use of one or to buy one as I head home to California. My Dad says I was stupid to start the trip with a car that overheated but I gently reminded him that when I came and got the car that I carried 70 pounds of tools on the plane as it was overheating when he gave up on the problem and "dumped" it on me. My engine timing is just by "feel" as I can not find a timing mark. My wife enjoys this car so much that now I am considering buying a whole second set of running gear and rebuilding it to keep this thing running until my Dad sells me his 98 deville ... not as pretty but it is a Northstar that does not leak oil with 60k (my cousin was the first owner) and surely 32 valves must be good for something. We have driven this 92 Deville about 50K every year we have had it. My Dad drove it 20k in 10 years buying if from the dealer as a "new demo" with 10k on it at purchase. Drop me a note and I will tell you all that I have learned playing with this car and its overheating problems. It and my youngest daughter's 91 Olds with an intermittent die anytime after the electronic dash loses data has been a car education for me and I was once a fully certified NAISE Master Mechanic. Both cars now run great. Now I am trying to get this one to run right ... I don't want any more codes 22, 26, 52, 55, 70, 85, 97. Most of those I have mastered, so now I am seeing only 22 and 70 on a regular basis. I just kill them while driving and continue on without stopping. Also disconnecting the battery helps drivability and resets the TPS values ... I don't understand all that I see about that issue. I was shocked to test my Dad's 98 Devilleand find 5 codes all OBD2 codes that I know nothing about. (I am looking for a manual paper or CD/DVD). He was a bit concerned too as I called them up in his speedometer. He thought it was running perfect. (-; All of my TPS problems started after I cleaned my throttle body as I reassembled my motor. Before my forced engine teardown, I only had an ABS pump code error. That error came with the car. After I install a new heater core then I will go after that code. The heater core is 100% plugged up with too much cooling tab goop as was the water jacket arond my cylinders which I now feel restricted the water flow and lead me to replacing 4 water pumps in the last two years. That job finally got easy with repitition but the first time was a real pain. Now you have my two cents ... by the way my 92 4.9L runs consistantly now at 97-98C as per the fuel data display and the onboard computer diagnostics. I figure that is 204-208F. When sitting still after a trip to the store the IAT is also about the same even though the outside air tem was 84 yesterday. I rarely use my air so I don't know how that affects it but when I get this car home to my wife she will surely tell me as she ALWAYS runs the air where we live in Sun City, CA ... one of those places that can have 100 days in a row over 100 degrees. I welcome feedback. My best wishes to you. ibmpro@ez2.net Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.