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VK running hot

Discussion in 'VB - VK Holden Commodore (1978 - 1985)' started by 1985VK, Oct 5, 2018.

  1. 1985VK

    1985VK Active Member

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    There are lots of threads about commodores running hot or overheating and lots of ideas on how to deal with it from changing the thermostat to putting in electric fans etc. An often overlooked issue is a bad fan clutch not pushing enough air. It is easy and cheap to replace.

    Another thing that will make your ride run hot is a slipping harmonic balancer, especially if your volt meter is running low and are having battery problems as well ... if you are not sure put a bit of a mark on your balancer and line it up with another mark on the timing cover and crank the engine or take a drive ... if the marks have moved then the harmonic balancer is slipping on its mount and it is time to change it ...
     
  2. the_boozer

    the_boozer no more VK

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    Since I was 25 I've probably put more original fans back on vb-vk commodores than thermo fans on them. In the 15 years I drove the 1964 design of holden 6 only once did the harmonic balancer fly off of course I was 100 miles from home when it happened the water pump belt did stay on the aircon pulley for that drive home on the battery. I've had more water pumps fail than harmonic balancers . Maybe Im pretty lazy and only look under the bonnet once every couple of months now days why i can't drive a commodore anymore.
     
  3. 1985VK

    1985VK Active Member

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    It is amazing what bolting on a new fan clutch can do when the car has overheat issues. It can drop the temp back into the blue or near enough rather than having the car running well over 3/4 on the gauge. It is a simple fix.
     
  4. sire01TMK

    sire01TMK Member

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    What brand fan clutch do you use?
     
  5. 1985VK

    1985VK Active Member

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    It was just an aftermarket version and i got it on Ebay from a major car parts seller. I suppose you could try and get the best brand you can get. I don't remember the brand and i don't know how many different factories are churning them out. I did not think it would make such a difference but i was amazed at the difference it made.
     
  6. sire01TMK

    sire01TMK Member

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    I might check out the dayco ones.
     
  7. 1985VK

    1985VK Active Member

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    That rings a bell. I might have picked up a Dayco. Summer is coming fellas, so check your fan clutches.
     
  8. bfhoon

    bfhoon Member

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    My vk 308 runs about half on the guage sometime it creept to 3/4 on a hot day I was insanly worried about it. I got one of those digital laser temp thingos which put my mind at ease a bit. I cant remeber the exact reading but at about half temp I think the car was close up to 100 degrees the pipe coming back out of the radiator was generally 5-10 degrees cooler than the water coming into the radiator obviosuly I could only check while the car was idling. I always though the ideal spot was bang on the 2nd line but mine is usually over that it just fluctuates which annoys me but the laser temp sensor eased my mind a bit. Mine prolly runs a bit hot though since its m21 4 speed warm motor and 4.11 diff gears.


    A thread I started is below which will have the exact details of the digital laser temp reader.
    https://forums.justcommodores.com.au/threads/vk-v8-temp-gauge-anyo.270017/
     
  9. DerekP

    DerekP Member

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    The gauge if working properly in conjunction with the temp sender should read just below half way or half to just over under load and on a hot day. Check or just replace your clutch fan; do a full cooling system flush (properly!) with new good quality coolant, replace all hoses including heater hoses; replace thermostat. Ensure the auxiliary electric fan comes on when the A/C compressor kicks in, replace it with a bigger one as I did would be my advice (assuming you have A/C...).
     
  10. Lacksballs

    Lacksballs Active Member

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    What a number of people forget is that the poor old radiator has been out in the elements for years & years, collected mud, bugs, birds, leaves etc etc. And without fail the radiator nor condenser (if fitted) are removed regularly and cleaned. Without air passing though the radiators "fins" the engines coolant cannot cool efficiently. As a truck mechanic we had to remove cooling packages yearly & those vehicles that ran throughout the night more frequently, with out fail most were clogged with bugs mostly stuck between the intercooler & radiator. So don't under estimate the importance of having a clean & efficient radiator.
     
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  11. bfhoon

    bfhoon Member

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    Yep do 1000 kilometre journey through the country on a warm night absolutely incredible the amount of bugs and crap you catch on the fins Imagine a truck doing 5000 kilometres per week at night wouldnt take long.
     
  12. Mia's vh ss

    Mia's vh ss New Member

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    The fan should always be the first place to look and thermostat, i drilled a couple of small holes in the outer rim of the thermostat making the car run cooler but only if there is no other cooling problems
     
  13. commy vk

    commy vk Active Member

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    I have to agree with this 100% that's why I stayed away from thermos
    also being from the old school
    Heard too many stories of not cooling down at all.
    Get a new clutch fan or test the one that's on already and if there is a little resistance
    when turned by hand it is probably ok.

    Make sure there is coolant,not just water and water pump is all ok.
    To check the Wpump grab the blades at 9oclock and 3 oclock and try and wiggle it side to side
    and if there is side play then it's time for a new one.
    Another way to see if it's ok is to look from under the car to under pump and if it's leaking from the small hole
    it's cactus.
    Make sure the shroud is there and the plastic trim on top of radiator is also there.
    I fitted a trans cooler years ago and even when I tow the gauge is just off the blue.

    Hoses should not be overlooked and changed regularly,including heater hoses.
    Thermostat should be also checked using the boiling water in pot method.
    NEVER drive the car any further if the gauge ever in the red as it can become critical
    and causing severe engine damage as a result.
     
    Last edited: Dec 6, 2018
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  14. vc commodore

    vc commodore Well-Known Member

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    Late reply, but I have a warm 202 red....I'm running a 3 core radiator, a 75 degree thermo stat (from memory), 1X 16" davies craig thermo fan and 1X 12" unknown brand thermo fan....I run a davies craig thermo fan control unit, set to turn the fans on at 90 degrees and off at 85 degrees....There is no shroud....I have a brock style grill, which has the air flow impeded by 2 spot lights and a light bar....On a stinking hot (35+ degree day), in stop start traffic, the fans turn on and off at the prescribed temperature set. I have had it in this configuration for 4 or so years so far and happy to report the only time it got over 90 degrees was when the radiator developed a leak in 5 cores, due to a thermo fan rubbing. Other wise, no problems...

    Out on the highway, the temperature sits between 75 and 80 degrees, depending on the outside temperature and whether I'm climbing a hill...So needless to say, the fans don't turn on..

    I have had the radiator repaired (wasn't coughing up close to $700 for a new one) about a month ago....Since it's been repaired, there have been a few hot days (around 32 degrees) and I am happy to report, it's still staying in the correct temperature range....The fans themselves were 2nd hand when I bought them and had them fitted to another motor for over 10 years , prior to fitting them to the current motor....

    So I'll leave it upto you which direction you head
     
  15. the_boozer

    the_boozer no more VK

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    Using the air-con in traffic was where the people complained the temp went to high put it back to the factory fan made their problem go away the next owner of the car that didn't care about a bit more power maybe, just service it once a year, its the only car i have so i don't want it to break down I guess all those cars and 1/2 of the owners are dead by now. old thinking maybe hotrod blokes use the newest stuff they can get their hands on because its better and love cars so are prepaid to spend the money on good gear.Not cheap **** speed shop crap boy racers buy. Ever had a shitty when the you beaut 8000rpm speed shop special fan went thru the bonnet
     
    Last edited: Dec 4, 2018
  16. figjam

    figjam Donating Member

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    Reading this reminded me that I always used a Craig Davies thermo fans on my old agricultural Holden engines, 186, 202 and 253. Blowing from in front of the radiator.
    No overheating ever, I did not use the sensor, I had them wired to a on/off switch on the dash.
    The engine noise generated by the old fans was considerable, and taking the fan off made a huge difference. You could safely put your hands in around a running engine without losing a finger.
    And the removal unleashed more HP than any Chevy badge.
     
  17. vc commodore

    vc commodore Well-Known Member

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    My Davies craig fan is at the grill side of the radiator, whilst the 12" one is engine side of the radiator...The car was aircon when I bought it, but I didn't have all the bits, so didn't bother chasing it up....got 4 windows, so that's plenty for me

    I have seen the u-beaut alloy flex fans let go with nice results on bonnets...That's the ones with the blue centre and alloy fins

    I also believe factory aircon cars had a small thermo fan at the front of the air con radiator.....It was so small,(I reckon it was about 6" across) I doubt it'd blow your hair out of place....

    And another thermo fan plus....Inlaw has a 304 powered VK burnout car....All he is using is a VN thermo fan mounted engine side of the radiator....He spins it at 6,500 RPM for 3 minutes in top and has no cooling issues...He is also running an electric water pump.
     

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