HomeForumsTechnical – GeneralEngine308 V8 Overheating, I Think ???

This topic contains 11 replies, has 5 voices, and was last updated by Profile photo of gtrboyy gtrboyy 2 years, 7 months ago.

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  • #20267
    Profile photo of VHSLE CRUISER
    VHSLE CRUISER
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    Member since: October 1, 2016
    Posts: 38

    My car is a VH 308 5ltr.
    Im not sure if my car is having heating issues of if im reading into it.

    My car has no power lose, oil level are fine, coolant level are fine although noted that near every time when I drive my car i notice coolant is dripping from the  radiator overflow hose.

    When I drive my car for say 15mins go through the gears up to 60kms…the temp gauge is reading about 1/4 and after a 1hr drive the temp gauge is reading at time 1/4 up to 1/2 but usual dropping off  to 1/4…

    On the last drive, when it was raining I noticed that my bonnet was semi steam a little but my temp gauge was only reading 1/4…

    Cheers,

    #20268
    Profile photo of cava454
    cava454
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    Member since: February 20, 2015
    Posts: 2 145
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    Re bleed the system and double check tstat is working correctly.

    #20269
    Profile photo of VHSLE CRUISER
    VHSLE CRUISER
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    Member since: October 1, 2016
    Posts: 38

    I know how to bleed my system but how do I test the thermostat ?

    I may end up replacing my thermostat but do I go for a 160 or 180,the factory VH Commodore was 160 ?

    Straight coolant or a 50/50 coolant/water mixture would b fine but what about just straight water ?

    Cheers,

    #20271
    Profile photo of cava454
    cava454
    Moderator
    Member since: February 20, 2015
    Posts: 2 145
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    Put in a running kettle and see if it opens.

    Run what the factory t/stat is. It should be 180

    #20274
    Profile photo of Immortality
    Immortality
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    Member since: August 31, 2015
    Posts: 512

    Standard thermostat for the 308 V8 in the early Commodores was a 190° F unit but I to would recommend a 180° F thermostat.  I would also consider changing the radiator cap.  Does your bonnet have the lining underneath?  I’ve had bonnets do something similar as it really does get fairly warm under there and without the lining it would be more noticeable.

    Been a long time since I drove a VH but those temps sound fairly reasonable.  When it gets hot can you hear the fan come on?   Those mechanical fans with the fluid coupling can wear out.  When they are working good you will definitely notice it as they get quiet loud when it starts pumping air.

    #20330
    Profile photo of VHSLE CRUISER
    VHSLE CRUISER
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    Member since: October 1, 2016
    Posts: 38

    I dont have and unboonet lining.

    I do a radiator flush out and see how the temps go, and then look at the thermostat after and possible replace with a 180f rated thermostat.

    Cheers,

     

    #20332
    Profile photo of gtrboyy
    gtrboyy
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    Member since: January 20, 2016
    Posts: 191

    Sounds fairly normal mine 1/4 driving also would creep up to 1/2 sitting in peak hour traffic on warm day.

     

    There is block-off plate under front apron to radiator tiebar helps seal off that section.

    Some people dont have water bypass hooked up when they should (hose from water pump to thermostat housing)

    seized thermostat always good to check

    cast round impellor instead of crap star shaped tin in water pumps helps stop cavitating.

     

    clutch fan worn out or tired can be another…some leave off radiator shroud is big no-no.

     

    Early commodores have really good cooling system particularly when in good shape.

     

    #20337
    Profile photo of SLE-881
    SLE-881
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    Member since: March 1, 2015
    Posts: 81

    Temp sounds normal to me too.

    I just changed the thermostat and water pump on the VH. The needle was getting all the way to the red at a standstill and just over 3/4’s when moving.

     

    At first I thought it may have been the temp sensor or the temp gauge because it was fine one week then overheating the next. I bought a laser temperature gun as a back up which confirmed it was the pump. Since changing it the car sits at a 1/4 temp and might go close to half on a hot day sitting in traffic.

    Daniel
    Instagram - @SLE881

    #20343
    Profile photo of VHSLE CRUISER
    VHSLE CRUISER
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    Member since: October 1, 2016
    Posts: 38

    what about cold/rainy days my car is still at 1/4 – 1/2 temp on the gauge.

    Cheers,

    #20344
    Profile photo of SLE-881
    SLE-881
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    Member since: March 1, 2015
    Posts: 81

    Sounds right. Shouldn’t matter if the temp outside is cold compared to it being warm. The colder outside the longer it may take the engine to get up to optimal operating temperature.

     

    I don’t think the car is overheating and I suggest checking that the radiator cap is ok and you’re not overfilling the overflow bottle.

     

    Daniel
    Instagram - @SLE881

    #20345
    Profile photo of VHSLE CRUISER
    VHSLE CRUISER
    Participant
    Member since: October 1, 2016
    Posts: 38

    The previous owners I brought my car off they removed the coolant res bottle,I fill up my radiator till it full to the radiator cap.

    How do I test my radiator cap?

    Cheers,

    #20347
    Profile photo of gtrboyy
    gtrboyy
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    Member since: January 20, 2016
    Posts: 191

    If it looks old just buy new cap & be done with it.

     

    These need overflow bottle as it’s recovery type coolant system..

     

    Last time mine was out on cool night was just on 1/4,assume that was where thermostat open/closed

    With most cars just ‘cos it says gauge says 1/4 or 1/2 could mean anything & vary from car to car or model

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