Wow this is an old thread! I guess I forgot to comment on what happened. I did get my thermostat replaced but it didn't change one thing. The temp gauge still never goes above 2.25/6. The only thing I can think of is to replace my O2 sensors. Something that has been on my to buy list for a while . All I can say is that having your temp gauge low does not necessarilly mean something is wrong. My car runs perfectly, who knows, maybe changing the O2 sensors will fix it. No worries.

 

How is your fan clutch?
If it's stuck, then your fan will cool all the time. This will usually be felt right away as loss of power, unless you've been driving like this forever. In that case, it's pretty hard to tell.

 

my temp runs between that mark and the next one up. According to the owners manual ( 1990) , it states that it should be right where yours is.

 

Change the thermostat yourself, don't go to the mechanic. remember to buy the aluminum washer for the fill bolt on to of the thermostat housing.

 

I was under the impression that these cars had clutch fans, rather than electric fans?

 

I have two Zirgo 16" electric fans and its running all the time. My temp is in the middle like most people stated. Earl!, u should get a water temp gauge and test out the true temperature. Auto Meter have few nice one. I would be suprise if your temp gauge is broken.

When I took out my cluster, i noticed the temp needle move up and down. Few times i noticed it got stuck. Get an after market water gauge and test out the system.

 

my 92 also runs right at half way, regardless of how I have been driving. As for the electric fans in the front of the car, they are for the air conditioning. I got to replace them when I hit a deer!. Even when the plastic "air conditoning" fans were broken, my temp never went up when I drove the car home.

 

My 95 LS has been showing temperature variations all over the range of the gauge, mostly high. I changed the thermostat and nothing happened, as the variation was still there. It runs at normal temp when I am moving but when I get in slow bumper to bumper Cali traffic, it starts to go high and approach the red area. I try to turn my heater to full blast, and sometimes it works, and other times it does not, and it even blows cold air when the gauge is showing a high temperature. Any ideas?? Fan Clutch? How much to repair?

 

When the car is cold from just starting up, the ECU sets the A/F ratio to about 8:1. This is called open loop because the O2 sensors are not up to operating temperatures, hence the open in open loop. The O2 sensors are not sending a signal back to the ECU and not closing the loop. This would account for the terrible gas milege during cold engine startups, the rich fuel smell in the exhaust, and the horrible emmisions. When the engine is warmed up, the O2 sensors are at operating temperature and are relaying a signal to the ECU. The ECU is finally able to correct A/F ratios for the maximum fuel efficiency thus entering closed loop.

The thing about the temp gauges is that even though the temperture flucuates within the recommended operating temperature, the gauge will not show it. This is purposely designed so that worried owners would not be running to the dealers everytime the gauge jumps to almost 3/4 or dropps to 1/4. The needle is meant to stay around the middle until the temperature skyrockets to the red.

petrojeff, Im not sure if the 95 LS's had a shroud for the radiator or not but the shroud helps direct air throughout the whole radiator when the car is not moving because there is no wind blowing through the parts of the radiator where the fan is not blowing. this causes the car to overheat when it is not moving such as in traffic as you described and to be perfectly normal when moving because of the air running through it. If the fan clutch is not working, the same problems would arise because of the same concept, no air moving through the radiator to cool it down when in bumper to bumper traffic. As for your heater problem, try having the heater core looked at because the hot radiator coolant is what heats up the heater core, thus heating up the air. Does the car leak any coolant? Did you change the termostat yourself? If so, did you put it in backwards or did you put so much gasket seal that it might of clogged the passage or blocked the thermostat from moving? If not, make sure the mechanic didn't. Well thats all I can tell you now because I am not aware of the details of your problem. Good luck. LS_4Will

 

Thanks for the reply LS_4 it sounds like I may have two problems. First the fan clutch and then some kind of restriction or failure of a valve to open during the heater demand process. I have a very good independent Lexus mechanic that put in the new thermostat, and I know he put it in right. I spoke with him on my cell phone when I was driving my 95 LS yesterday and it was still doing the same thing with the temp fluctuations and the heat would come on and off. During our conversation my mechanic said we should check for some sort of blockage in the cooling/heating system, although I think I will have him check the fan clutch first, replace it if necessary and then see if this alleviates the problem in the heating system. I also noticed that when I initially start the car,sometimes it idles low and very roughly unitl I get up to speed, it is as if there is a load initially on the engine(possibly bad fan clutch putting increased load on engine?) and the symptom goes away upon getting to traveling speed ,as I said. Any further observations or ideas from you experts would be appreciated.

 

Fan clutch is a known problem on the LS. However, when it fails, 99% of the time it gets "locked", meaning that it does not slip any more. Instead, it turns at engine speed all the time. This results in significant power loss and increased noize from the engine bay. Once the clutch is locked, it usually stays that way forever. When this happens, engine will only run cooler due to the fact that the fan is always on. What you have does sound like some kind of blockage in the cooling system that gets wedged in some passage. On the other hand, that would have to be a large piece of debris and how in the world could it get into the system???
Before replasing fan clutch, I would check the actual coolant temp with an independent device. That will tell you whether your gage is telling the truth.

 

This sounds like the same troubleshooting path my mechanic is taking, and it does make sense. I do believe that I will not replace the fan clutch and try the temp measurement and maybe a flush first. Although the lack of the fluctuation at speed still puzzles me.

 

Rice,

So the fan clutch may be the problem. If I start the car on a cold day and immediately open the hood and see the engine fan running, then it's stuck, right? It sounds like you know a few things about this problem. Is this something you dealt with in the past?

My info is showing the fan clutch as a $224 part list. Is it hard to replace? It's listed as only .8 for labor but I have a feeling it may be tricky to replace. Does anyone know?

 

when I had to remove and re-install the fan in the incredibly cramped engine bay of the 300ZX, it took about an hour or maybe even less. I have never tried on the LS but I dont think its much longer, but still I have never tried . LS_4Will

 

Earl,
The fact that your fan turns when the engine is on, does not necessarily mean that your fan clutch is bad. Fan always turns, but not always at the same speed as the engine. If you idle your car long enough, and your fan clutch engages, you will hear the difference. Fan makes no sound when the car is cold and the clutch is disengaged. As soon as the clutch engages, you hear how engine begins to struggle and the air starts pumping.
It is an expensive part, but it is very easy to replace. All you need is a 10cm wrench and 20 minutes of your time. No tricks there.