padgett Posted December 12, 2008 Share Posted December 12, 2008 I really miss the readouts from my 88 on the 90, the digital gauges seem somewhat vague.For example after changing to the 180F thermostat and reprogramming the fans, I compared the display to ED04 and found that each bar above would illiminate when it passed these temperatures:1 bar - 38C2 bar - 47C3 bars - 54C4 bars - 63C - TCC begins to operate5 bars - 74C6 bars - 82C (halfway)Even with the 195F thermostat, I never saw it get over six bars so it must go to at least 200F (93C) before the seventh bar illuminates.Now GM gauges have never been the most accurate but the coolant readings on the ALDL seem to be very close on all of my computer cars. Since it is critical for adjusting the a/f mixture and the advance, it must be accurate.Now I would really like to know if the temp ever goes over 185F but with 180-200 all in the same bar, that is unlikely. If I ever get the time to decode the BCM, I may fix that.In the meantime if I ever see that 7th bar (one past halfway) light up, I am going to be concerned. Now on a stock system with a 195F thermostat and fans that do not come on until 207F, the seventh and even the eighth are probably common. I just find that everything lasts longer and runs better if the engine is kept just a little cooler and there is still pleanty of heat at 0F (been there, don't like it) with a 180. Link to comment Share on other sites More sharing options...
Guest Richard D Posted June 27, 2011 Share Posted June 27, 2011 F@rd had a better idea as to the dim witted customers, the oil pressure gauge in my 94 T-Bird would would alway go to exactly center of normal. Idleing with cold oil, 3,500 RPM with cold oil, idleing at 650 RPM with hot oil it would never change. Found the schematic and the oil sender was a on/off switch with a fixed resistor in line with the "meter" When asked we were told that customers were complaining that at idle the gauge was showing 10 PSI which is in spec acording to Ford but customers were wanting new engines, bearings, etc. Nice fix, NAH! Link to comment Share on other sites More sharing options...
Ronnie Posted July 31, 2011 Share Posted July 31, 2011 I'm working on a chart for my website to give an approximate temperature (in degrees) of what the '90-'91 temperature gauge is showing with the blocks. If someone would continue where Padgett left off and give me the ED04 readout as the blocks go past half way for each block it would be helpful. The photo below shows what I have so far. I would like to continue on with the labels up to the hot mark if possible. Thanks Padgett for your contribution so far. Link to comment Share on other sites More sharing options...
NCReatta Posted July 31, 2011 Share Posted July 31, 2011 Ronnie, I expect this is just for cars with a 180* thermostat? Because, if you're running the stock thermo, then half way on the gauge would be about 202-208. Link to comment Share on other sites More sharing options...
padgett Posted July 31, 2011 Author Share Posted July 31, 2011 a) Thermostat has nothing to do with it. Those are the temps for each bar. Halfway could mean anything from 180F to 209F thought I did, just do not have it all the way.180F: half way210F - one bar over center217F - two bars over center221F - three bars over centerKeep in mind that this is not really a gauge, it is a digital display defined by a map. As each pre-programmed temperature is reached, the next segment lights. To know know the real sender reading, you need to look at ED04. Link to comment Share on other sites More sharing options...
Ronnie Posted July 31, 2011 Share Posted July 31, 2011 Marck, I was basing the chart I made on numbers posted by Padgett in his first post. I would think temp readings should be he same at half way regardless of the thermostat used but I don't know for certain. I don't have a '90 so I can't check the blocks versus the temp reading (ED04). Do you have something that suggests 6 blocks would be 202-208 degrees F? Link to comment Share on other sites More sharing options...
Ronnie Posted July 31, 2011 Share Posted July 31, 2011 a) Thermostat has nothing to do with it. Those are the temps for each bar. Halfway could mean anything from 180F to 209F thought I did, just do not have it all the way.180F: half way210F - one bar over center217F - two bars over center221F - three bars over centerKeep in mind that this is not really a gauge, it is a digital display defined by a map. As each pre-programmed temperature is reached, the next segment lights. To know know the real sender reading, you need to look at ED04. If I continue on with the graph will it be a useful tool to give a good approximation of the actual temp of the engine? Will this be a good rule of thumb for those who don't know how to check ED04? I don't want to post a chart that will mislead someone. Link to comment Share on other sites More sharing options...
NCReatta Posted July 31, 2011 Share Posted July 31, 2011 Padgett and Ronnie,Padgett's post cleared things up for me. I didn't know that the center bar could be such a wide range in temps. I suppose it would be good to say that center is simply operating temp? Link to comment Share on other sites More sharing options...
Ronnie Posted July 31, 2011 Share Posted July 31, 2011 Should my labels be at the leading edge of the blocks instead of the trailing edge? Would that be a little more accurate? Maybe in the middle of the block? Link to comment Share on other sites More sharing options...
Guest Squire Tom Posted July 31, 2011 Share Posted July 31, 2011 center bar is obviously operating temperature , 3 bars past center means pull over before you have trouble. turning off the air is probably a bad thing as you would lose some fan operation. better to turn on the heater if you are running too hot and can't pull off the road.ormaybe not.is there a way to have the actual reading noticeable while driving? Link to comment Share on other sites More sharing options...
Guest Squire Tom Posted July 31, 2011 Share Posted July 31, 2011 forgot.. older engines had a tap in the block for a mechanical gauge - what about the series 1 ? Link to comment Share on other sites More sharing options...
Guest Richard D Posted July 31, 2011 Share Posted July 31, 2011 If it really gets hot it will shut off the A/C for you. On my first 1990 coupe I was in Fort Pierce (about 80 miles from home and my temp gauge ran all the way HOT. I pulled into a gas station, long story short thermostat was stuck closed. After it cooled I borrowed a wrench and removed it. I ran it for a few days without a thermostat and it would climb to one bar before center, sometimes going to center. Of course it was 90 degrees or so. Link to comment Share on other sites More sharing options...
padgett Posted August 1, 2011 Author Share Posted August 1, 2011 Well the temp sender is under the throttle body, probably one of the warmer places in the engine. If it follows conteporary gauges, all the segments is probaly 260Fish.It is posible to start a cold engine, go into diagnostics, and just note the ED04 reading as each segment lights. That is what I did.Mine are turned to run between 180F and 190F so had to have one I had not fiddled before I could get readings past the center. Link to comment Share on other sites More sharing options...
Ronnie Posted August 1, 2011 Share Posted August 1, 2011 i have one more question for '90-'91 owners. Would the chart be helpful on my website or should I drop this idea as something that is really not needed? I'm neutral on it myself. Link to comment Share on other sites More sharing options...
padgett Posted August 1, 2011 Author Share Posted August 1, 2011 For those used to idiot lights, it is probably best to think of it as low, normal, high. If you really want to know, see ED04 and understand centigrade. Link to comment Share on other sites More sharing options...
jonlabree Posted August 1, 2011 Share Posted August 1, 2011 My computer readout reads 88 degrees celsius at the center mark, which is 190.4 degrees fahrenheit. It has a 180' thermostst in it and runs normally on the center mark in the summer.The gauge on the dash is all but usless, as it's reading vary so much. Next step is a good water temp gauge. Link to comment Share on other sites More sharing options...
jonlabree Posted August 2, 2011 Share Posted August 2, 2011 According to the manual the top reading on the gauge is 303' F Link to comment Share on other sites More sharing options...
Ronnie Posted August 2, 2011 Share Posted August 2, 2011 Thanks Jon for the information. I haven't decided if I should continue with the graph or not. Reading the blocks and trying to relate them to a temperature in degrees seems to be vague at best and there doesn't seem to be be much demand for such a chart. Link to comment Share on other sites More sharing options...
jonlabree Posted August 3, 2011 Share Posted August 3, 2011 The temp gauge readings have been bothering me for quite a while. It always seemed to me to be incorrect. So, I did a little research.According to the shop manual the gauge has a range from 40C = 104F to 151C =303.8F with a difference of 199.8 and 13 bars on the gauge. That means each bar on the gauge stands for 16.65 degrees. So bar 1= 104 degreesBar 2 = 120.65Bar 3 = 137.3 Bar 4 = 153.95Bar 5 = 170.6Bar 6 = 187.25Bar 7 = 203.9 Middle of gaugeBar 8 = 220.55Bar 9 = 237.1Bar 10 = 253.7Bar 11 = 270.4Bar 12 =287.05Bar 12 = 303..4This means to me, that the gauges are worth about as much as a bore pig with T--sNeedless to say I have ordered an external temp gauge and will get to the bottom of this. Link to comment Share on other sites More sharing options...
Ronnie Posted August 3, 2011 Share Posted August 3, 2011 Jon, whoever did the picture in your signature did a really good job. I find myself looking at it a while each time I read one of your posts. Link to comment Share on other sites More sharing options...
padgett Posted August 3, 2011 Author Share Posted August 3, 2011 Only one difficulty: that list is theoretical per the shop manual. Mine was by observation. The "guage" values are definately non-linear. Link to comment Share on other sites More sharing options...
jonlabree Posted August 3, 2011 Share Posted August 3, 2011 Are you saying the shop manual is wrong again?And it's not theoretical, it's mathematical. Link to comment Share on other sites More sharing options...
padgett Posted August 3, 2011 Author Share Posted August 3, 2011 Based on the theory that it is linear. I was not questioning the math, only the premise. Frankly I have never seen a GM dash gauge that was linear (except maybe the speedo) or even particularly accurate. Link to comment Share on other sites More sharing options...
jonlabree Posted August 3, 2011 Share Posted August 3, 2011 Never the less, the starting temp and ending temp are correct according to the manual.I find the ending temp to be ridiculous. By the time the engine reached 303 F the engine would have quit and melted or warped a valve or valves and god knows what else. Link to comment Share on other sites More sharing options...
padgett Posted August 3, 2011 Author Share Posted August 3, 2011 Where did you find that? I have a suspicion what it is but want to see it please. Link to comment Share on other sites More sharing options...
Guest Squire Tom Posted August 3, 2011 Share Posted August 3, 2011 according to the linear interpretation , 2 bars over center should be spitting fluid.i think padgett's are more realistic.again, is there a capped port in the block that could be utilized for a mechanical gauge? Link to comment Share on other sites More sharing options...
Ronnie Posted August 3, 2011 Share Posted August 3, 2011 According to the shop manual the gauge has a range from 40C = 104F to 151C =303.8F with a difference of 199.8 and 13 bars on the gauge. That means each bar on the gauge stands for 16.65 degrees. So bar 1= 104 degreesBar 2 = 120.65Bar 3 = 137.3 Bar 4 = 153.95Bar 5 = 170.6Bar 6 = 187.25Bar 7 = 203.9 Middle of gaugeBar 8 = 220.55Bar 9 = 237.1Bar 10 = 253.7Bar 11 = 270.4Bar 12 =287.05Bar 12 = 303..4Based on the theory that it is linear. I was not questioning the math, only the premise. Frankly I have never seen a GM dash gauge that was linear (except maybe the speedo) or even particularly accurate.Jon. wouldn't 6 bars lit be half way as I have marked on the chart I made? It seems it would be 6 instead of 7 since there are a total of 12 bars. Notice that my marker is between bars 6 and 7.Anyway, I could finish the chart using data observed by Padgett for bars 1- 9 and calculated data for bars 10,11 & 12. But my question is would the chart be useful to anyone if it was on ReattaOwner.com. I agree the chart is not going to be an accurate representation of the actual engine temperature. My intention is to give a non technical person a general idea of what the temp gauge is trying to tell him. What do you guys think? Link to comment Share on other sites More sharing options...
jonlabree Posted August 3, 2011 Share Posted August 3, 2011 If you start with the first line on your chart, there are 13 with the seventh one being the center. Link to comment Share on other sites More sharing options...
padgett Posted August 3, 2011 Author Share Posted August 3, 2011 If I ever get the time, replacing the sender with a pot is trivial, then we can match the bars to specific values and compare to the sender.I suspect that the 303F reading is simply what a value of FFh would be and 00h is -40h. I suspect the range of the sender is more like 0-260F so the limits should never be reached (and should trigger an error). Link to comment Share on other sites More sharing options...
Guest steveskyhawk Posted August 3, 2011 Share Posted August 3, 2011 Could the use of a digital infra red thermometer at least verify some of the normal operating numbers? Link to comment Share on other sites More sharing options...
jonlabree Posted August 3, 2011 Share Posted August 3, 2011 I suppose it could, but where do you take the temp. It varies greatly under to hood.Thermostat housing would be a place to start. If you could get your infra red gauge to point at the temp sender it would reflect the temp there. Link to comment Share on other sites More sharing options...
Guest steveskyhawk Posted August 3, 2011 Share Posted August 3, 2011 Exactly. You could at least determine the near exact temperature that your thermostat opened Link to comment Share on other sites More sharing options...
jonlabree Posted August 5, 2011 Share Posted August 5, 2011 OK, with a reliable new temp gauge hooked up. Idling. Reatta gauge at center, Gauge reads 179'. Sending unit is right above the thermostat. Link to comment Share on other sites More sharing options...
Guest steveskyhawk Posted August 5, 2011 Share Posted August 5, 2011 Sounds perfect. Rather than opt for expensive and complicated "fixes" for some mechanical issues I go for the simple. I have put a new radiator in a car and it eliminated those "excursions" above half way on the temperature gage. New Radiator is only about a hundred bucks. Link to comment Share on other sites More sharing options...
padgett Posted August 5, 2011 Author Share Posted August 5, 2011 I usually just flush radiators and cooling systems with a garden hose until clear, let drain, then add a gallon of pure antifreeze and enough distilled water (78 cents a gallon) to top off. Repeat every few years. Case of antifreeze does the herd. Link to comment Share on other sites More sharing options...
Guest steveskyhawk Posted August 5, 2011 Share Posted August 5, 2011 I suspect that a radiator on a car that has 100,00 miles or more has lost some of its ability to exchange heat as it was designed to do. Road debris (be it microscopic) contaminates the outside and there is a certain amount of scale inside any used radiator. If this combined contamination reduces efficiency as much as 15% is the radiator adaquate at say 100+ degrees with the air on? How much was it over built to begin with? Under these conditions have we exceeded the margins? We all know that the bean counters ruled in the 80s and 90s. I dont suspect the radiator was too big the day the car was built. I'm just sayin. Link to comment Share on other sites More sharing options...
padgett Posted August 5, 2011 Author Share Posted August 5, 2011 Do know the Reatta radiator is about 10% smaller than the one in a 90 Bonneville with 3800. OTOH I have never had any problem running my cars around 180F with a proper SuperStat and reprogrammed fans at 95 degrees ambient/100F at the hood inlet.. Link to comment Share on other sites More sharing options...
jonlabree Posted August 5, 2011 Share Posted August 5, 2011 Previously I posted the fact that I installed a new oversized "ALL" Aluminum radiator, larger fan units, and a 180 thermostat. I also power flushed the system and am running 50/50 antifreeze.The car ran at the center mark at highway speeds and above, but after it went down to street speeds it would move up notch. I haven run it at street speeds long enough to find out if it would cool down to the center mark yet.The new gauge will tell me the truth now. Link to comment Share on other sites More sharing options...
Blue90 Posted August 6, 2011 Share Posted August 6, 2011 Jon,I'm considering a new radiator; the car still has the original with almost 209,000 miles.Would you elaborate more on your oversize replacement?Thanks. Link to comment Share on other sites More sharing options...
padgett Posted August 6, 2011 Author Share Posted August 6, 2011 Portland ? Personally, I have never had an overheating issue with the stock radiator if everything else is right. NP holding 80F over ambient. Link to comment Share on other sites More sharing options...
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