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Vx no radiator pressure

Discussion in 'General' started by Vxutehrt, Oct 2, 2019.

  1. Vxutehrt

    Vxutehrt New Member

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    Hi guys I've got a vu with an Ecotec and it has been dumping it's coolant/water once it hits 100c
    It has a lot of brown build up inside radiator but not oil. Oil looks ok, the digital engine temp says it's only about 100c but seems hotter to be honest.
    Also there is no pressure is Radiator hoses they seem soft?
    Any ideas I'm going to buy new radiator cap in morning but not sure
     
  2. Skylarking

    Skylarking Well-Known Member

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    Any brown buildup is usually indicative of rust within a system because the coolant hasn’t been changed as required. And rust residue for your alloy Ecotec block equates to the cast iron cylinder liners (if wiki can be trusted) corroding.

    So, it seems you need to consider flushing the system clear any of the brown residue to restore cooling efficiency. This usually means a chemical flush. BUT if an engine cooling system hasn’t been well maintained, such a flush could result in a number of new leaks developing and it depends how bad things actually are. Usually post chemical flush leaks occur within HVAC radiator behind dash, engine radiator and/or possibly hoses, etc...

    So I’d suggest pop by a decent mechanic you trust as they can test the radiator cap, the radiator top where the cap sits as well and the general system for coolant leak. They should also test the radiator water for combustion gasses. This should be a five to ten minute job and they shouldn’t charge much for this service but it will give you valuable information as to how big a problem you may have. They could then give you a price to service the cooling system should you desire.

    But, if it’s found it’s just the cap, you can do a clean water flush (with low pressure compressed air to agitate the water) and you should be able to get most of the crap out. Remember to have the heater on during the flush. Fill up with new “coolant” and pop on a new cap and hopefully all is good from then on.

    Be warned though, driving a car around which does not build up water pressure will lead to loss of water to the point the temp gauge wont work in some cars. This can and does killing engines. So don’t put it off and if you must do short trips, check water level before each drive.

    WARNING: on an engine, always check that the hose has no pressure by squeezing the radiator hose before opening the cap to its first stop. Wait for any pressure to be released, if any, then remove cap. If the hose is hard when squeezing, the cooling system has pressure and you should not take the radiator cap off until the coolant pressure drops as it cools. Taking the cap off a hot system can result in serious burns.
     
  3. Vxutehrt

    Vxutehrt New Member

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    Thanks I put a new radiator cap on and got pressure back in the hoses, went for a 30km drive both crusing and in traffic had temp mode on dash it never went over 91 so I hope it's all sorted but I bought new coolant and thermostat so will flush system and install thermostat and coolant in tomorrow.
    Never knew a radiator cap is so important.
     
  4. Skylarking

    Skylarking Well-Known Member

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    Relatively cheap outcome being just the cap.
    Good luck with the flush :)
     
  5. immortality

    immortality Home of the smoky breakfast Bacon! Staff Member

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    Yes, a radiator cap is critical to the performance of the cooling system. Monitor your coolant level, brown gunk in the cooling system is also a common sign of the intake gaskets failing as well a rust build up if you don't have the proper corrosion inhibitor protection in your coolant.
     
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  6. Vxutehrt

    Vxutehrt New Member

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    How do I get the overflow bottle out from behind my headlight do I have to take the bumper off?
    I've got no reserve tank it's weird I'll post a pic maybe previous owner removed it
     
  7. BarelyHoldenOnTogether

    BarelyHoldenOnTogether New Member

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    Why did you let the cooling system get so bad? You're obviously using water since there's brown rust build-up. Stop using water. Do a flush and use proper coolant. Cars this side of the 1972 202 red motor don't run well with water alone as it corrodes everything and doesn't cool the engine hardware properly. More modern cars cooling system parts rely on the lubricating and protecting properties of coolant to ensure water pumps dont seize up.

    You can flush it out at home and do a good job.
    I usually recommend firstly flushing the radiator by taking the hoses off and running the hose through the radiator until clean water comes through.
    Then remove the thermostat and give that a nice clean - test it open/closes by putting it in hot water if it opens, all good.
    Clean out the overflow bottle too.
    Then I'd fill a big 20L bucket with tap water and let it sit in the sun to warm up a bit. Reconnect the bottom radiator hose, but leave the top radiator hose disconnected. Fill the radiator with water, then run the engine with the heater running at full temp, and wait until you see water coming out of the top hose. As water comes out, keep filling up the radiator with the warm water in the bucket until you see clear water coming out of the top hose.
    Then reconnect the top hose, undo bottom hose to flush out the radiator and add 50/50 coolant/water mix to the radiator.
     
  8. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    Not all right, no lubricant in coolant.
     
  9. Vxutehrt

    Vxutehrt New Member

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    I'm still having overheating issue just found my tube going to pod filter is badly split would this be the cause??
     
  10. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    As long as there no air sucking in after the MAF as it will make it run crap, I say buy a new radiator yours is probably partly blocked if it was that bad, if it was me I would replace your water pump too.
     
  11. Skylarking

    Skylarking Well-Known Member

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    Have your cooling system tested for combustion gases. Then do a pressure test of your cooling system. This will give you good information about the condition of your head-gasket and/or any internal/external leaks. Such tests should be done with the system hot...

    Also, the cooling system is a sealed system which will over flow some coolant (via the radiator cap) into the overflow reservoir as the engine heats up and then such it back as it cools down. As such the overflow reservoir is critical to the system performance. If the overflow bottle is missing, you must get another overflow bottle to replace it. On a VF, the overflow reservoir is accesses from the drivers wheel (jack up, remove wheel and wheel liner to get to the reservoir)

    Lastly, the cooling system is very dependent on: coolant flow (created by water pump), on clear water passages within the engine and radiator, the correct volume of coolant without air locks in the system, and correctly functioning radiator fans. Any one of these parts not functioning as intended can can cause cooling issues.

    So, if you've had corrosion within the cooling system, don't discount the water pump paddles being shot and thus they can't efficiently push/pump the fluid around. You may have to pull out the water pump to visually check the paddles/fins.

    As to checking if a radiator is blocked, an old school test was to feel the front of the radiator where blockages would feel colder as compared to the parts where the hot coolant could flow through without issue. Obviously, this is more difficult to do in modern cars due to aircon condenser on the front and radiator fans and their ducting on the back. Maybe you can temporarily remove the fans and shrouds so you can feel the rear surface of the radiator for cold spots. Just be warned you don want to stick your fingers through the fan shroud with the fans connected as they can start at any time and you'd thus loose your fingers if/when the do start spinning. So best to remove the fans and shroud so you can feel for cold spots.

    If all things seem to check out OK, double check to ensure you have gotten all the air out of the system (which can be a real pain). An air lock will stop water from flowing where it needs to and things can't be cooled corrctly and engine damage can ensure.

    If it's too much for you, take it to a trusted mechanic...
     
  12. Trevor loves holden.

    Trevor loves holden. Well-Known Member

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    When my inlet manifold was leaking oil into the cooling system I had no issue with overheating or dumping water just slime milky crap at the radiator cap.
    If your intake gaskets never been done I would recommend doing it, around 80 bucks and say 3hr job to do 4 max, ( good time to replace injector filters and seals at the same time. ) When I replaced my radiator as it sprung a leak in the core 2 weeks latter heater tap gave up too, best to do it right than been stuck in summer under the hot sun on side of the road. Replace the lot if they never been done.
     

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