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Hi, looking for an opinion on my Oil Temp and Water Temp.
1990 L98, base coupe, 25,300 miles,
first pic is after cold start in garage, second pic after 55 minute drive over 25 miles with mix of traffic and highway back into garage.
New to me since July 2021, running smooth, no problems. My ESTIMATE of the oil Temp according to gauge scale is 120F and water Temp at 150F, which both are rather low, if my estimate is correct. I initially thought those gauges were not working because they didn’t appear to move for the longest time then when they did you could barely see it happening. So, is this something I need to run down and correct or am I wrong on reading the gauges?
Thanks for any ideas you might have.
Brad
I would inspect what the ECM is seeing with a scanner, and then the thermostat. It shouldn't be that low, even a 160F stat has a hard time keeping coolant at 160F unless its below freezing outside. PO may have taken the stat out entirely.
Thank you very much everyone, I do have the C68 so I'll check that and dig in and see if I actually have a working thermostat installed.
It seems to run pretty smooth but I haven't owned an older car in quite a while. I did forget one thing: it is usually very hard to start when cold, first time for the day. After that first try everytime, even after 4 or 5 hours of sitting.
Anyone will, if if they are subscribed to the thread. And a responder will if they have "automatically subscribe" enabled. And only if they have "email notification" enabled in their User Control Panel. I have none of these enabled, so I don't. So it depends on the individual's desires and his preference settings.
Just wanted to follow up on this temp issue. So I found my way thru the electronic air system and on #16 I was getting a dead cold reading of 44C, which is probably just the lower limit the gauge or sensor measures. After the engine was running for approx five minutes the temp would increase by one degree about every five or ten seconds to 48 or 49C and then in a rush jump 20 or 30 degrees at a time up to 115C and then slowly stabilize at 118C, which is 244F. This is stop and go traffic with a few minutes here and there at 55MPH and ambient air temp of 65F; everything I have found around the forum and net says that is normal for this car. The quick rush of temp from 49C to 115C tells me I do have a thermostat I just don't know which one. Also, once it makes it to this operating temp it never drops below 116C until it is off for a few hours. So with the picture of my water temp gauge reading low is it possible it is displaying a centigrade reading even though it is a fahrenheit gauge? Anyway, thanks for all your help with this.
I'm going to go out on a limb here and say that 244f is a bit on the high side...
As far as the display, I am not sure. I know factory calibrations incide most ECMs use Celsius vs Fahrenheit (which is why the data stream is in C perhaps) but I am unsure if the dash can simply be switched over to measuring that. I would guess not and that something else is going on potentially.
You need to use the digital display to see temps, those gauges won't tell you much other than a rough indication.
Yes. You need to look at the digital gauges for more accurate readings. There was a sticker on the dash, to be removed by owner only, that said the analog gauges were not linear and you should consult owners manual for info
Hi everyone, I'm still working on this water temp issue and have found there was a WORKING 195F thermostat installed so I took it out, sealed it back up and topped it up with water and a new radiator cap. I ran the engine while monitoring the temp readout (#16) on the electronic air conditioning. Before cranking, the temp was displaying 44C, for five minutes it worked it's way up to 50C and then like I previously wrote, it quickly shot up to 115C. I began to suspect the readout of the water temp going to the computer was not correct so I broke out my laser temp gun and took readings around the thermostat housing neck and other areas that were close to the circulating water. I was getting readings between 120 and 130F while the computer was seeing 230 to 245F from the sensor in the front of the intake manifold.
So I ordered a new sensor and installed it along with a new water temp switch between #6 and #8 in the head (for the dash gauge). I again topped up with water but left off the radiator cap and let it come up to the max temp it was going to get without the cap on. The temp readout on the AC display went to 115C (240F) while my laser temp gun was getting 120 to 140F and I put a BBQ meat probe into the open radiator cap and was getting 128F in the coolant liquid. I put the cap on and drove around for about 25 minutes. When I checked the temps with my laser I was getting around 160F around the thermostat housing neck and along the top radiator hose while the readout on the AC display was at 119C.
SO, does anybody have ideas of why my old and new water temp sensor is giving way way off temp readings, oh yeh, my dash gauge read just as low as before, even with the new switch. Could something be wrong with the engine control module? The car runs good except for hard to start when cold for the first time in the morning but then starts first crank throughout the day, even after sitting for four or five hours. I thought when I put in the new front temp sensor it was going to solve my hard cold starts and high temp readings but now I'm at a loss for what to do. I forgot to mention, I put the new radiator cap on because nothing was moving into or out of the coolant overflow tank since I got the car last July.
Oil and Water Temp
