tjenkins

To me anyway, it's vitially important that I now where the short is/was. Can you provide the location of the electrical short?<P>--Tom

Best of luck - I went through 2 months of this, and while I never did find the problem, mine does cool back down at 'speed'.<P>Please keep us all apprised of exactly what you do and the results you obtain.<P>--Tom

My nozzles are starting to clog up (please, no Viagra jokes .<P>I called the dealer and found out that there is a complete/total kit for $30 per side that I can order. However, it also apparently includes all the tubing and clips etc.<P>I just need the middle and end nozzle assembles, times two for both blade assemblies. Does anyone have a part number for just the nozzle part? Note that the middle and end nozzles are different.<P>--Tom

Go to <A HREF="http://www.reatta.net" TARGET=_blank>www.reatta.net</A> for a radio connector schematic. Specifically, <A HREF="http://www.reatta.net/faq.html#CDPLAYERS" TARGET=_blank>http://www.reatta.net/faq.html#CDPLAYERS</A> and go down a few pages.<P>--Tom

Seen in a local paper:<P>90 Black Coupe. (724-593-6297, ask for Rick Smith).<P>I've not seen it, but did talk to the owner. Last 6 of VIN=904204.<P>Black external, Blue internal, black moulding. 195,000 miles, at 165,000 a factory rebuilt engine was installed.<P>No, CD or Sunroof, bought near new in 1990 in Greensburg, PA.<P>Again, I just talked to Rick - I have not seen the car, and am just relaying what he provided over the phone.<P>--Tom

As of today, 25 July 01, I've made a decision.<P>Based on both the outstanding, and learned comments above, coupled with my first hand experience, I've decided to 'turn up the radio'.<P>In other words, I'll reinstall the Stant 82C/180F thermostat, and call it a day. Why am I doing this? Simply because at a certain point, the law of diminishing returns applies. I've either changed, replaced, or confirmed just about every electronic/electrical, in addition to mechanical device in my cooling system. If indeed it is 'factory' to "heat-soak" the engine at no speed (stopped traffic - with or without the AC on - I confirmed this yesterday, temp rose without AC), I accept the apparent fact that the design engineers knew and/or fashioned all the parameters into the final cooling sytem product.<P>Even though I will state emphatically that my vehicle *NEVER* rose above the 12' bar position on my analog gauge, I will accept the group recommendation to leave as is.<P>However, if someone would like to sell me a reprogrammed EPROM that would enable my low-to-high speed fan operation at 98C (vice 109C), let me know <P>--Tom<p>[ 07-25-2001: Message edited by: tjenkins ]

Today, I confirmed that there are no exhaust gases in the coolant.<P>Quick and easy test. While warm, the mechanic turned on the engine, and used a fat syringe bulb device, half-filled with blue fluid. Opened up the pressure cap, and sucked in the gases from the green coolant.<P>Since the blue fluid did NOT turn yellow, a rather sure-fire test, apparently I do not have a head gasket leak.<P>I did email, and then call, the main Buick Technical Support team. Spoke to a Rick there, but after I had explained what I had done so far, he had no other suggestions.<P>I also asked him about a flushing methodology, but apparently Buick doesn't recommend anything more than the fluid flush.<P>I'll watch and record the above BD27 and 28 values over the next day or so, however, I'm running out of ideas.<P>An afterthought - can I coerce my AC hight side to go >65C earlier, causing my fans to go from low to high (and then recooling the engine back down)? Why would the high side remain cooler than 65C, even with hot weather outside?<P>--Tom

Today, with the ambiant temperature around ~92F, the ED04 coolant temperature rose steadily.<P>Sure enough, the AC high side TEMPERATURE reading (BD27) hovered around 30-40C. After 20-30 minutes this afternoon, in traffic, the AC high side temp rose to 64C, one degree shy of the factory low-high fan turn on. I would have let the engine idle to check, but really didn't have the time. At this point, the ED04 temp was at ~109C.<P>To simulate turning the fan(s) on from low to high, I pulled the two wires to the AC high side temperature sensor. Sure enough, the temp rapidly lowered to 93C. I drove with the fans on high for 3 miles, at 10-15 MPH, and the temperature hovered around 93C. So, lesson learned is that if I could enable the low-high fan transition below 109C, or lower than 65C AC high side temperature, my problem would be solved.<P>I'll attempt to repeat this tomorrow, and let the engine idle up to, and hopefully passing, the 65C AC high side temperature. If this circuit is acting normall, I should be able to see the low to high transition at that temperature.<P>I'm also going to verify exhaust/no exhaust gases in the coolant tomorrow.<P>--Tom<p>[ 07-23-2001: Message edited by: tjenkins ]

Did you have the A/C on? I am beginning to wonder if in fact the high side temperature sensor doesn't contribute to the low --> high fan speed, albeit without higher than (what you would expect) normal temperatures in the coolant.<P>In other words, even with a non-hot engine (~105C?), with hot ambiant weather outside, the AC high side would rise above the predetermined threshold of 65C and turn the fans from low to high.<P>--Tom

Anonymous,<P>Could you pass on the details here? I'm EXTREMELY interested in how and why the dealer (?) downloaded a new program into your computer.<P>Please *REPLY* via here or via email to:<P>tjenkins@hawaii.rr.com<P>Thanks in advance.<P>--Tom

Yes... bought a K-Mart kit, and made a wooden mount. Glued and held it for 3 hours in the sunlight. Seems to work like a champ.<P>Thanks!<P>--Tom

I need confirmation and the location of AC high-pressure temperature switch.<P>Per the 1990 FSM, page 1B1-5, Figure 3, the *HIGH* side temperature switch is located by/at item 3, toward the middle portion of the dual row of AC piping underneath the black plastic cowl on the top of the firewall.<P>My car has 3 sensors and two sizes of piping.<P>The right side sensor (drivers side), attached to the smaller of the two pipes, has BLUE and BLACK wires out of the connector.<P>The middle sensor is connected to the larger diameter pipe, and has WHITE and BROWN wires from the connector.<P>The left hand side is also connected to the smaller pipe, and (hard to see) has black and white (?) wiring.<P>Could someone confirm that the FSM is wrong? Is the larger pipe the high side of the AC system? If so, then the above and manual do not match. If the small size, then my car matches.<P>Note page 8A-31-2 for wire colors.<P>In fact, I opened the right hand side (drivers side) sensor and checked ED27 - sure enough, it was a -34C (or some close value). When I shorted the sensor with the BLACK and PINK wires, the temp rose to 240C (or close). At this point, both fans turned on to HIGH. However, the sensor was on the smaller of the two pipes.<P>If true, and both opening and shorting of this right hand side sensor (drivers side) causes ED27 to go low and high, with the resultant fan operation changing from low to high, this would account for the stabilization of the motor coolant temperature.<P>In other words, if the above is true, my problem may indeed be a lower-than-normal AC high side temperature. As the temperature increases outside, if the AC high side also does not increase, my fans would never go from low to high in hot weather.<P>I'll watch ED27 over the next week.<P>Again, can someone confirm the exact location (smaller or larger pipe) for the AC high side temperature sensor?<P>Thanks VERY much in advance.<P>--Tom

Good idea on checking the AC high side temp. I'll watch it over this week.<P>Btw, is there a way to manually switch both fans from low to high?<P>--Tom

Outstanding...Stan, please tell me on what page did you find that info?<P>--Tom

Ok, so per the 1990 FSM, the fans go from low to high with either condition being met:<P> 1) Coolant temperature exceeds 108C/226F, or,<BR> 2) High side AC temp exceeds 65C/147F.<P>Since I run the AC on all the time, I wonder if the fans were at high over the last three years, and somehow, the fans are now on low speed?<P>My AC doesn't seem REALLY cold, but it's no warmer than it used to be...<P>--Tom

Help...<P>Car in warm weather today, sun beating down on the windshield. When I wasn't looking , the rear view mirror just dropped off.<P>Seems the glue that holds the small thick metal mounting plate gave way.<P>I'm set to go to NAPA or Checkers - does anyone know if what they have works, and if so, do I need to 'prep' the area somehow?<P>--Tom

Three things:<P>How did you get the PROM reprogrammed to enable both fans (on high speed?) at 175F?<P>I went to NAPA today - sure enough, they offer a $50 kit that can test for exhaust gases via coolant. However, this NAPA also has a motor shop, and for $17, they'll do the same one-time test. I'll let you all know how it turns out.<P>And, someone please confirm 90 fan rotation. My two fans, on slow speed, seem to turn in opposite directions from each other. The blades for both fans do seem to 'pull' and 'push' correctly, but it's odd that both fans turn in different directions???<P>In the meantime, Stant's 82C/180F thermostat is going in tomorrow.<P>--Tom<p>[ 07-20-2001: Message edited by: tjenkins ]

Outstanding... this is one of the things that I still need to check.<P>In fact, after 3 days at the dealer, I had asked him about a cylinder head leak. His response "yeah, I was thinking about that".<P>Gosh, if he WAS THINKING ABOUT IT, WHY DIDN'T HE INITIATE IT? Oh well, film at 11.<P>I'm going to R/R the thermostat back to a 82C/180F Stant unit - will ask about the test kit when I get to NAPA.<P>--Tom

Thank you ALL for the various recommendations. It seems that this is not a 'normal' problem in one sense, but rather common for the 3800.<P>In light of that, after having the dealer now re-replacing the thermostat with a factory OEM 195F unit, and the R/R of the lower hose to factory as well, I'm going to watch the temp over the next 2-3 weeks to gather data.<P>The dealer also confirmed good pump pressure as well as non-leaking water pump.<P>In the meantime, I'll R/R the 3 relays for preventive measure. I've also looked at, and am convinced that there is no blockage on/near the A/C condensor coil(s).<P>In short, the vehicle experiences this symptom:<P>In cold/warm weather (for what that's worth in Hawaii , the temp is 90C/195F +/-10C.<P>In hot weather, the temp slowly jumps to 25-30C higher than the nominal 90C/195F temp. Symptom is exacerbated by in-town and stop light driving, yet drops back to normal with a 5-10 minute 60MPH speed.<P>Confirmed yesterday at the dealer than the FSM does *NOT* indicate when the fans go from low to high, but lead mechanic indicates normal threshold is (get this) 240F!!!<P>I've have yet to see the high speed fan relay kick in.<P>I'll take the above comments to my non-Dealer mechanic and have him concentrate on engine internals (leaking head gasket etc).<P>"You can lead a horse to water, but you can't make him float on his back."<P>--Tom

Status as of today... Dealer indicates he's 'perplexed' and can't find anything wrong. Says water pump is good, with good output, and no orifice restrictions. Anyone have any ideas?<P>Note details:<P>Initial:<BR>Over last 3 years, temperature gauge has been solid straight up (84F-99F) during both cold and hot weather. Over last month, temperature rises steadily. Dealer can't find anything wrong.<P>Symptom:<BR>Measured ED04 computer readout, coolant temperature rises normally to ~90C/195F, then, either after 30 minutes or in hot(er) weather, the coolant temperature slowly but steadily rises to over 119C/246F (a differential of nearly 30C/50F). After >10 minutes on freeway, temperature slowly drops back to ~88C.<P>Background:<BR>1990 Buick Reatta (same as Riviera), 3800 engine, bought used at dealer in 1997 with 33K, presently 77K. Driven daily with AC on all the time. Routinely flushed and changed the coolant with Prestone every year. Water pump changed on 16 June 1998, at 41,869 miles.<P>Over these last three years, my analog temperature gauge has quickly warmed up and has always pointed straight up at 12 oclock (9 bars, with 4 on the left, one straight up, and 4 on the right). The temp gauge has ALWAYS exhibited this straight up condition during times of cooler as well as hotter weather, either on the highway or idling for long periods in town. Based on measure temperatures, a straight up analog condition ranges from 84C to 99C - well within the 90C +/-5C range.<P>I watch the instrument panel all the time.<P>Details:<BR>Since early May, while at a stop light downtown after running for 45 minutes, the temp gauge climbed to 1, then, 2 oclock.<P>I changed the existing thermostat (which I assumed was an OEM 90C/195F but cannot now confirm that) with an after market 90C/195F NAPA unit, but no change. Upon starting up in the morning to go to work, it quickly rises up to normal 12 oclock position, and stays there until 30 minutes later when I pull into the parking lot. However, in the afternoon, when the outside temperature is higher, upon arriving back home from both highway and city driving, the gauge reads 1 bar to the right at 1 oclock, then, 2 bars, etc.<P>Entering in the on-board computer readout (ED04), the temp bounced from 88C-93C or so during the first 30 minutes, then, in the afternoon going back home, the temp would rise to 95C, 100C, 105C and then, up to 119C. Fans have not gone to high-speed mode, since the temperature apparently didn't exceed a predetermined value.<P>This is/was a change in the normal operation for this particular car.<P>18 May 2001 - Brought into dealer:<BR> R/R Radiator cap<BR> R/R coolant<BR> R/R coolant sensor<BR> Checked/swapped the ECM and BCM computers<BR> Indicated that the Instrument Panel Cluster was bad (reading too high). I bought a used IPC from PA and had them send it to me. I installed the IPC and it provided the same temperature gauge readout as the original IPC.<BR> <BR>Wanting to prove the coolant sensor/ECM/BCM/IPC combo were good, I went to Radio Shack and bought a 5K ohm potentiometer. Warming up the car, I removed the plug on the coolant sensor, and took several measurements, substituting the potentiometer for the coolant sensor. Readings confirmed factory settings and values:<BR>Temp Ohms<BR> 85C 261<BR> 90C 233<BR> 95C 197<BR> 100C 178<BR> 105C 164<BR> 110C 126<P>Bar 'switch on analog gauge':<BR> 84C 12 oclock<BR> 99C 1 bar (1PM)<BR> 102C 2 bars (2PM)<BR> 105C 3 bars (3PM)<BR> 109C 4 bars (4PM) <BR>It does appear that the coolant sensor through both computers to the IPC is good. Subsequent trip to Kuroda Radiator confirms correct coolant temperature with infrared pyrometer aimed at the coolant elbow on engine block. See attached spreadsheet.<P>8 June 2001 - Thinking that the radiator was bad, or blocked, I had a radiator shop R/R the complete radiator assembly. Although the original aluminum core radiator was not plugged, it did have some cracks in the plastic tanks on the side. Good preventive maintenance I assume, but did not change the situation.<P>12 June 2001 - Changed the NAPA 90C/195F thermostat with a Stant Premium 82C/180F non-linear thermostat. Currently, the car quickly warms up to ~85C, then again, in warm weather slowly climbs to 109. Again, this is a temperature differential of nearly 30C.<P>Parts confirmed good by either replacement or testing:<BR> Radiator<BR> Radiator Cap<BR> Coolant sensor<BR> Thermostat<BR> Both pusher and puller fans (confirmed high speed when manually jumpering relay)<BR> BCM/ECM/IPC combination<BR> Wiring<P>13 July 2001 - brought into dealer, who says they confirmed no abnormalities. Coolant good, water pump pressure good, and can't find any restriction. Dealer is "perplexed".

VIN, Price?<P>--Tom

Barney, you mention it was 106 outside.<P>What was the ED04 reading when the temp gauge went from straight up to one bar to the right?<P>From one bar to two bars to the right?<P>--Tom

WAIT!!!!!!!!!!!!!!!!<P>Barney, please CONFIRM the above when you indicated:<P>" believe you will find the only way they will fit is with the pointy end down."<P>??? I swear that when I took mine out, and replaced it, that the pointed side was up toward the hose going to the radiator and the round copper sensor was down toward the engine block.<P>Please note an excerpt from my ALLDATA CD-ROM under Thermostat:<P> <A HREF="http://www.reatta.net/graphics/010621_thermostat.gif" TARGET=_blank>http://www.reatta.net/graphics/010621_thermostat.gif</A> <P>--Tom<p>[ 06-21-2001: Message edited by: tjenkins ]

Thanks for the info and your situation Gary. Have you checked the temp via ED04 on the ECM readout?<P>I too have had this problem, albeit rather suddenly. Over the past 3 years, my analog temp gauge was solid (straight up). Over the past month, in warm wx, it started to climb after 30 minutes or so.<P>After several weeks of troublshooting, and replacement/checkout of components, I'm still not yet positive why the temp climbs.<P>My next step is to remove both heater hoses from the water pump and verify that there is adequate pressure from the water pump (like a garden hose vs trickling out).<P>So far, components checked good and/or replaced on my vehicle include:<P>thermostat<BR>pressure cap<BR>radiator (orig was not blocked)<BR>ECM<BR>BCM<BR>IPC<BR>hoses (does not collapse when hot)<BR>coolant sensor<BR>grounding and wiring<BR>both puller and pusher fan(s)<P>And, as of this week:<P>o I run the car *ALL* the time with auto/AC on. Ergo, both fans are running in the serial mode all the time, and therefore, are on slow speed. As I recall (Barney, correct me if I'm wrong) at 115C, the main fan relay switches, and energizes both fans in at parallel, effectively increasing both puller and pusher fans to high speed. I have yet to see this condition though.<P>o I have confirmed that the 'normal' temp now is 84-88C in the morning/on the highway, and 88-99C in the afternoon and in town. This is a differential of 15C.<P>o Now, with the Stant Premium 82C unit, the analog gauge always points straight up and niether shifts right nor left. This *WAS* the normal indication on this particular car over the last three years. Either the original 'stat was an 82C unit, or, indeed, I have a blockage of sorts - or some other obscure cause.<P>o The other day, I invoked the heater in 88F weather The temp lowered a bit from 88-85ish, but then rose right back up to where it was. Thinking that the heater core would act as a heat sink, if true, the temp would have remained low. However, the indication was that it bounced right back up. This seems to me that the thermostat compensated for the greater cooling capacity through the heater, and closed accordingly (making the temp rise back up).<P>o The more I think about this, the more I'm convinced that the coolant sensor, both computers, IPC, thermostat, radiator and pressure in the system is satisfactory. There are only a few other things that come to mind, the first being a tertiary blockage, or, some sort of blow back/by into the cylinder head area. And, of all things, sans pulling the water pump housing apart and confirming that the impeller blades are indeed good, at this point, I'm inclined to confirm the temp at the coolant sensor in the radiator shop and simply "turn up the radio".<P>And, just the other day, I confirmed three things:<P>o At the radiator shop, infrared pyrometer reading was 200F when the digital gauge indicted 91C, so if memory serves, 200F is 93C, so 2C differential is, I suspect, within tolerance from the coolant sensor over to the IPC. Of course, the IR reading can't be THAT accurate, but probably no more or less than the digital gauge driven by the $18 coolant sensor :0<P>o Yesterday was warm, at 92F. Temp gauge rose to 101C (one bar to the right - Padgett, there are actually 6 bars right and left, not 4 - I was mistaken). This would confirm more than a 15C variation in coolant temperature.<P>o When hot, I had my wife raise the rpm to 2K, and felt the lower hose (that was replaced 3 years ago at the dealer when replacing the water pump). It did not collapse, or withdraw, but it was very warm (hot) and rubbery to the touch. I'm not sure what 15pounds of pressure is supposed to feel like, so I couldn't tell you if there was pressure in the lower hose or not.<P>--Tom

Now that I've had it in for a few days, with the 82C/180F Stant Premium thermostat, normal morning temp is 84C-88C, highway or town.<P>Afternoon highway is also 84C-88C, occasional 92C. In town it rises from 88C to 98C.<P>As Padgett indicates, I suspect a 3-5C higher reading due to the 'off-reading' coolant sensor.<P>Even with my particular temperature rise problem, with the 8C lower Stant thermostat, at least I'm compensating for the higher [than normal] temps.<P>If you have the time, I would really appreciate if you folks could take your coolant temp, both in town and highway, and post herein. It would be interesting to see what 'normal' span of temperature ranges there are now with these 10 year old cars.<P>--Tom