Announcement

Collapse
No announcement yet.

Overheating Problem

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Overheating Problem

    Hi Everyone,
    This is the first time I've asked questions in a forum, hopefully I've done it right.
    I have a overheating problem I hope someone can help me with. I have a Toyota Prado, Diesel, Auto, Year 2000.

    The temperature rises dramaticaly on a long incline when the vehicle drops down a gear, this happens on the freeways. If I just slowly drive, without it kicking down, going about 60klm an hour it doesn't over heat, but if I put my foot down the temperature goes into the red. It doesn't overheat in normal driving or bumper to bumber traffic on hot days, only seems to be on long incline on freeways eg. (NSW) the m1 at Ourembah (heading south), the Hawksbury (heading south) and the high country (Hume hwy Victoria). No extra weight in the car and not towing anything.
    I replaced the Radiator (new) and thermostat, apparently the water pump is OK and had the head replaced (wasn't replaced because of the overheating problem).
    I've tried searching for answers, the only other thing I have come across is the "viscous fan hub", but I'm thinking this would cause overheating problems in more occasions than just the ones I'm having.

  • #2
    Mate I towed the camper down that way over Christmas and there's some good pulls, my old girl got hot.
    Viscous fan hub is worth a look.
    If the hub isn't working properly, it will cool the radiator OK in most conditions but on long inclines that fan has to be roaring.
    I have a diesel auto too and you get used to listening for the fan to cut in/out. When it cuts in, it might be just a gentle change in note but if the engine keeps getting hotter, the fan has to lock up and really make some noise.
    Another worry is that Toyota temp gauge. If it goes in the red the engine is REALLY hot.
    I have aftermarket gauges and the Toyota gauge will sit happily in the centre from about 70 to 90 deg C. Then it will start to rise but if it's red, you're looking at 110+ deg C which is too hot for these old girls.
    You can add silicon oil to the hub, costs about $20 a bottle from Toyota but it's a bit hit and miss.
    If you add too much the fan will be on 100% the whole time which really chews your fuel and robs power.
    Other option is an e-bay hub for around $120-$160.
    On the Mighty 90's Facebook page, a lot of guys have had a win with these cheap hubs. (I keep one for a spare)
    I've been down this road too, replacing radiators, cylinder head, recondition the auto, transmission cooler and so on. Viscous hub was the go for me.

    Comment


    • #3
      as carco said, check your viscous hub Bro. It should be the culprit by the content of what you say. As said above, even with a partially messed up hub it will be fine unless you floor or or inclines.
      VZJ95 Manual / DC5 Integra Type R / DC2 Integra Type R

      Comment


      • #4
        Thanks guys for your response, I hope this will fix it. This model is such a great 4wd. I looked on ebay and found a few, I looked on google and there were quite a few negative about viscous purchased on ebay.
        Would you think any of these would be ok, (just looking for opinions):
        1 - https://www.ebay.com.au/itm/Viscous-...wAAOSw8W5ai9p0
        2 - https://www.ebay.com.au/itm/TOYOTA-P...AAAOSwUKxYfWzj
        3 - https://www.ebay.com.au/itm/TRUFLOW-...gAAOSwn9VaX9Tl

        1 - Tora $115
        2 - from just 4x4 parts $159
        3 - Truflow $198

        Comment


        • #5
          Have seen all those mentioned on the Facebook page.
          mine came from online auto parts and was about $120.
          it's crazy cheap when compared to a Toyota one.
          they're quite complicated inside too

          Comment


          • #6
            For the cost of a couple of tubes of silicon oil from toyota (they were $10 - $20 when I did mine several years ago), you can follow this guide to fix your fan hub provided it doesn't have any evidence of leaks beforehand.

            https://offroad80s.com/how-to-top-up...an--t1160.html

            Silver '04 KZJ120~Manual~GXL~Dobinson/Kings lift~Custom valved Ironmans~Detroit Locker~Endless Air~X9 Superwinch~Madman EMS1~TJM Dual Battery~Rhino Roof Tray~120W solar panel~Foxwing awning~Bushskinz UVP~Long Ranger water tank~Bushman fridge~Steinbauer P-Box~Beaudesert 2 3/4"~Airtec Snorkel~TJM Sliders~Prico Boost Gauge~BFG-KO2s~TPMS~GME TX3420~Front and Rear Cameras~Ultimate Camper hanging off the back!

            Comment


            • #7
              Thanks carco, the first one (Tora) is from online auto parts $122.66 delivered. Ordered, now to test it out. I'll post the outcome, thanks again.

              Comment


              • #8
                Thanks adrian, I ordered one before I saw your post, thanks for that information, I'll still read up on that though.

                Comment


                • #9
                  Adding oil is the cheapest option by far, but it may take a few attempts to get it working correctly. There's no way of knowing the amount of oil still in the workings when you do a top up. Even if you empty the thing completely (and that oil takes days to all flow out) you'll find there's still some trapped inside !!!
                  You can also alter the cut in/out temperature just by loosening the 2-adjuster screws and rotating the valve, so it's a brilliant bit of gear but after 15+ years the oil quantity needs a top up.
                  As posted, if you add too much oil, the fan will never free wheel. That's great for cooling but the KZ loses a heap of power and fuel usage goes through the roof.
                  If you intend tweaking the old one, I'd recommend throwing away the PK head setscrews that hold the two halves together and replace them with Allen head bolts which will make it a lot easier to disassemble each time.
                  You'll need an impact driver to get the original setscrews out.
                  I take my fan/hub unit out through the bottom. I remove the bottom section of the cowl (2-clips) then the 4-12mm headed hub nuts and wriggle it all out between the transmission hoses.
                  On the bench, remove the fan then work on the hub.
                  When replacing, make DEAD sure those cowl clips are in properly. One of mine lost tension and the cowl came loose, got stuck between fan and radiator, chewed the fan to bits.
                  That was one brand new radiator too.

                  Comment


                  • #10
                    Update on Overheating Problem,
                    I received the viscous hub and installed it (very easy to do on the Prado). Took the Prado for a run to Coffs Harbour and back on the weekend, had NO problems with overheating, thanks guys for your input, this seems to have fixed the problem. Went up Ourimbah hill fine and the Hawksberry as well. Driving at approximately 2000 revs, kicked down a gear (automatic) and engine revs were about 3000 (revs don't seem to go over 3000, I suppose this is normal), temp guage never (noticably) moved.
                    Thanks again for your help.

                    Comment


                    • #11
                      That's good news.
                      Just a tip with the auto, she'll run cooler if you hit the button switching out of O/D rather than kicking her down.
                      Road speed in 3rd with converter locked is similar to O/D and converter unlocked.
                      Locked converter doesn't heat the trany oil, so that's also not heating your coolant.

                      Comment


                      • #12
                        Thanks carco, I'll try that. Good info, much appreciated.
                        Last edited by GrumpaR; 19-04-2018, 07:38 AM.

                        Comment

                        Working...
                        X