1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Fluctuating Temp Gauge

Discussion in '80-Series Tech' started by LACRUISERGUY, Mar 5, 2007.

  1. LACRUISERGUY

    LACRUISERGUY

    Messages:
    34
    Likes Received:
    1
    Joined:
    Feb 9, 2007
    Location:
    Los Angeles/Encino
    How's it going. I am new to the Forum and a new owner of a 1995 FJ80 Land Cruiser with 149,000. Over all my LC is in excellent condition. Mechanically it's been strong and not problems until recently. I've noticed on two trips I've taken up the Angeles Crest Hwy to the mountains that my temp guage starts moving dangerously close to the red and only when going up the steep inclines. When going downhill the needle starts to move back to the middle and is fine. I open the hood and see no problems. On one day only driving 60 fwy towards Pomona, again my temp gauge started getting very close to the red. I pulled over allowed it to sit for a bit, started on the fwy again and nothing. The temp gauge remained in the middle. I've taken it to the dealer twice and they could not duplicate the problem, or find any problems with the sensor's. Any suggestion on what else I can check?? Thanks.
     
  2. Darwood

    Darwood

    Messages:
    1,957
    Likes Received:
    6
    Joined:
    Oct 8, 2003
    Location:
    Z.O.W.I.E. Headquarters
    When was the last time your cooling system was serviced? A moving needle is not good. I bet your AC was cutting out as well if you had it on.
     
  3. cary

    cary

    Messages:
    3,118
    Likes Received:
    40
    Joined:
    May 7, 2003
    You are going to need to do a search on the raventai gauge mod (see the FAQ). The stock gauge has a 50f flat spot and does not move until about 230f. Basically, your truck is overheating badly. The usual cause is a combination of the fan clutch going bad (if you have the original, it is bad), and the radiator being partially plugged after 10+ years of use.

    The easiest/safest/most expensive route is to call cruiserdan (a member here who is the parts manager at American Toyota in Alberquerque and sells parts at a significant discount) and order 1) a new fan clutch, 2) a new 1994 radiator, and 3) a thermostat. It will run you about $500 for all delivered. Then follow the radiator replacement (and coolant flush) procedures in the FAQ. Assuming you don't have a bad Head Gasket, this will fix your problem 99.9% of the time.
     
  4. LACRUISERGUY

    LACRUISERGUY

    Messages:
    34
    Likes Received:
    1
    Joined:
    Feb 9, 2007
    Location:
    Los Angeles/Encino
    Thank's for the responses. I did a search in the Forum, came across some past threads. I did what appeared to be a simple test for the fan clutch, which was to run the engine to normal temp, turn off the engine and try to spin the fan. If it spun very easily and quickly, I guess this is an indication of a bad fan clutch, but if it didn't spin easily, probably not the fan clutch. Thank goodness my fan did not spin easily. So I have dropped off my Cruiser at the mechanic to have them do a complete cooling system flush, and to change out the thermostat. I know I probably could have done this myself, but I am not much of a mechanic, and until I learn more about the cruiser's I don't want to take any risk. I'll see what happens after this, and keep my finger's crossed it will fix the problem.
     
  5. NorCalDoug

    NorCalDoug problems solved daily...

    Messages:
    6,289
    Likes Received:
    106
    Joined:
    Oct 27, 2003
    Location:
    uhhhh...duh...Northern CA
    I had the same problem for about a year until last July.

    I noticed the temp guage would climb close to the red on hill climbs and when towing on mild grades.

    To try to pinpoint the cause of the problem, I decided to take a 3-pronged attack...but never got to complete my experiment. :whoops:

    I first flushed the coolant...no change.

    I then decided to change the fan clutch...but while I was doing that, I broke the small nipple that returns coolant to the radiator -- you know...that little one at the top...

    luckily for me, I had been planning to replace my radiator with a 93/94 OEM model, so I had that in my garage ready to go. I ended up replacing the radiator and the fan clutch at the same time. I also replaced the thermostat and all the associated hoses, since I was in there. It was about 5 hour job for me...and maybe a 1 and a half :banana: level job to pull the radiator and replace it.

    Once all this was done, I no longer had problems with overheating...not during long climbs up steep grades, not while towing...nothing.

    I'm not sure if it was the new radiator or the fan clutch or a combination of the two...but I'd betcha a shiny new nickel that your problem is with the fan clutch or the radiator.
     
  6. cary

    cary

    Messages:
    3,118
    Likes Received:
    40
    Joined:
    May 7, 2003
    If your fan clutch has not been replaced, it is bad, period. Spinning it when shut off does not tell you if it is good or not. If you don't hear it roar when you first start the truck, it is bad. You radiator is probably partially plugged also. It happens over time and yours has given you 12 years. Flushing the cooling system and replacing the thermostat is going to accomplish nothing at this point but to take money out of your pocket.
     
  7. e9999

    e9999 You want to do what...? Moderator

    Messages:
    16,582
    Likes Received:
    479
    Joined:
    Sep 21, 2003
    Location:
    US
    if the gauge is functioning correctly, there is indeed very likely a serious overheating condition going on. You are probably living on borrowed time and may be jeopardizing your head gasket health if you let it overheat.
    Be aware that the gauge will only move under serious overheating conditions (Cary, I think it's much more than a 50F flat. Mine gets to the middle around 130 and has not moved even when I was at 225F).

    I would not drive it around any more until the problem is fixed.

    First easiest and cheapest thing to do yourself is a forceful flush of the coolant system with a hose in the hope that a crud blockage might be loosened up (not likely that would fully solve things, but may help a bit).



    oh, and Welcome to the Forum!
     
  8. JZenger

    JZenger

    Messages:
    91
    Likes Received:
    0
    Joined:
    Jun 13, 2005
    Location:
    Salt Lake City, Utah
    I wouldn't count out your fan clutch yet. If you cruiser has the original fan clutch it is likely that you need a new one. There are other tests for the fan clutch that you probably found in your search. In particular, do you hear a roar at start up from the fan clutch? It should last a few seconds after start up. You can also do the grab test, which is not as bad as it sounds.

    Good luck.
     
  9. LACRUISERGUY

    LACRUISERGUY

    Messages:
    34
    Likes Received:
    1
    Joined:
    Feb 9, 2007
    Location:
    Los Angeles/Encino
    well guys, I had my cooling system flushed and the thermostat replaced. I also bought a fan clutch and thermostat and was going to have these installed as well, but as I drove out of the dealer lot my cruiser started to overhead badly, this time steam and water coming from the top radiator lining. Needless to say I am pissed because it wasn't this bad until after I had it serviced. So I had it towed to a reputable toyota mechanic (which I should have done the first time) and after having it 2 days he tells me the radiator has a very bad crack and he has been unable to repair it in order to do a pressure test of the system. Today, he calls to tell me the radiator is beyone repair and I will need a new OEM one at the cost of $525, plus he will install a my new OEM fan clutch which I already bought for a grand total of $800. He also told me that he is 75% certain this will fix my overheating problem. He can only give me a 75% guarantee for now because he has been unable to pressure test the cooling system or the engine due to the bad radiator. Can anyone give me the number to cruiserdan in New Mexico, I called information but I haven't been able to get the right dealer. I want to try and buy the radiator in hopes of saving some money. I hope this will fix my problem.
     
  10. landtank

    landtank SILVER Star

    Messages:
    18,955
    Likes Received:
    1,097
    Joined:
    Mar 27, 2003
    Location:
    Groveland MA
    800.432.6668 ext 8
     
  11. cam75w/ls1

    cam75w/ls1

    Messages:
    258
    Likes Received:
    1
    Joined:
    Jan 23, 2007
    Location:
    Texas, of course.
    Sounds like the previous shop didn't get all the air out of your system when they flushed it causing the overheating or they didn't get it full of coolant. I hope they didn't hurt the head gasket.:eek:
     
  12. DIHRD9R

    DIHRD9R

    Messages:
    26
    Likes Received:
    0
    Joined:
    Aug 31, 2006
    Location:
    Arizona
    overheating i've heard is a big problem with the LC's, and can lead to even bigger problems. :doh:

    apparently a blown head gasket is the worst case scenario...this has been drilled into me, so the cooling system is the first thing i'm looking at tomorrow.