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Motors Changing the coolant in a car?

Discussion in 'General' started by thelaw, 12 Mar 2012.

  1. thelaw

    thelaw What's a Dremel?

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    I bought a 91 2.0l primera today, just the standard model 4 sp auto.

    I am servicing it myself can see the previous owner was a bit of a cheap a$$ and just used water for coolant as it has that brown rusty look to it and in need of a change.

    I just wanted to confirm the below steps.

    i believe i empty the radiator out via the cock stop, refill the radiator with water, put all the caps back on, then run the engine with heater on hot/fans on, run it to norm temp, let it cool, them empty the radiator again of the water and that should help flush the system of any muck. (i may get a actual radiator flush fluid for this step tomorrow)

    Then I need to then refill it right up with 50/50 mix and run it again in the same manner ie heater on hot but this time with the radiator cap off to allow the air and gurgle to escape as it circulates?? and until the thermo/radiator fans kick in and that should avoid any air locks? Is that correct?

    I believe that is the process, i know this engine has the air bleed value near the thermostat that but i am not sure how to use it or if i can bleed/avoid any airlocks with just the rad cap off and running it up to temp until the fans kick in, before topping it up again?

    Thanks and i shall check back later to read your replies and other tips
     
  2. Picarro

    Picarro What's a Dremel?

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    I'd put at least some of the caps back on before you refill it - otherwise you'll end up with a very messy floor and not much coolant in the radiator.
     
  3. Smilodon

    Smilodon The Antagonist

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    The exact way of doing it depends on the make model of your car.

    In general though, the bleed valve sits on the highest point of the entire cooling loop. After draining it should be a matter of unscrewing the bleed valve, fill until coolant flow through the bleed hole.

    Running with the cap of the radiator would just introduce more air into the system (The fill point should be on the expansion reservoir.
     
  4. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    After you've emptied the coolant out (as much as you can) pull the hose off the bottom of the radiator, then the top hose coming out of the thermostat housing. Get your hosepipe and stick it straight into the thermostat housing (pull the stat out) and give it a good blast until the water runs clear. Repeat for the radiator.

    For refilling connect all the hoses back up, open up the bleed ports (there will probably be more than one), turn the heater on full hot (not always needed, but it varies across models). Then get a 2L bottle, cut the bottom off it, wrap the nozzle in duct tape until you get a good seal with it when you jam it into the radiator filler neck - this acts as an expansion tank, leave it connected when you run the car again.

    Slowly pour in your pre-mixed coolant (best off with blue for <98 cars) until it comes out of the bleed ports. Leave the rad cap off and start the car, run it until the rad fan kicks in, let it cool a bit and top up as necessary.

    As long as the temps seem alright run it again with the rad cap in place, sit inside and see if you can hear sloshing or running water, if you can you've got a bit of an airlock and need to try bleeding the system out again. If in doubt consult an owner's club/Haynes manual (or equivalent).

    :thumb:
     
  5. travisridesbikes

    travisridesbikes What's a Dremel?

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    While your at it, Replace the water pump & thermostat. It'll be worth it in the long run!
     
  6. Burnout21

    Burnout21 Mmmm biscuits

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    there is no reason to do that.

    Just a simple drain and fill as mentioned
     
  7. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    So cambelt, tensioner and idler pulleys as well? Because there's very few cars where the water pump's not cambelt-driven.

    Stats last so long that there's no reason to replace it unless there's a fault.
     
  8. RedFlames

    RedFlames ...is not a Belgian football team

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    After seeing 3 of my parents' cars go south because of them going... replace the timing belt/chain...
     
  9. Burnout21

    Burnout21 Mmmm biscuits

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    Im surprised at you Krikkit, you should know aux components are never on the cambelt, but the serpentine belt.

    Seriously unless the belts show sign of major wear just do them when required not 'just because'.
     
  10. Tomhyde1986

    Tomhyde1986 What's a Dremel?

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    If in doubt try to get a haynes manual or other workshop manual for the vehicle. That should give you the proper procedure.

    Personally I'm not that scientific. On my BMW 318 all I do is basically:

    1) Warm the beasty up and let it cool off. Personally I dont do anything with the heating.
    2) leave it running on the drive for a while.
    3) Undo the bottom radiator hose.
    4) Once water has stopped flowing out reconnect it.
    5) Pour water in while squeezing/releasing the bottom pipe to prevent really big air bubbles.
    6) Start the engine once thats done and leave it to run for a few minutes and re-check the water level as it's most likely dropped right down low.
    7) Add coolant to the radiator until it fills up to the required amount.
    Repeat step 6 and 7 until the level stops dropping

    Important:

    Do be gentle with it and check it over the next 2 or 3 days as it works out more and more bubbles. The water level might drop a bit. Just fill up as needed.

    It's an old car that got from London to Peterborough without any oil in it so it seems pretty hardy. If in doubt follow the proper procedure.

    In essence it's exactly the same as others have described just with a little less finesse :D. I'm not saying it's the right way I just know my vehicle doesn't seem to object. Once you know the vehicle quite well you kind of learn what you can and cannot get away with.
     
  11. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    In my experience the water pump is typically in the cambelt - I know it is on all the Peugeot TU/XU series engines I've got my hands dirty on as well as quite a few others including my Mrs' Focus.
     
  12. Burnout21

    Burnout21 Mmmm biscuits

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    Just found what your on about here, and it makes me sick! Any play in the pump bearing and the tensioner takes a pounding.

    My renault engined volvo ran everything on the serpentine belt, cambelt doing what it should do, and my saab uses two chains, one timing chain and the other powering the oil pump and water pump from the crank. Then a belt to power the aux components like PAS pump, alternator, etc.

    Genuinely shocked and sickened by a cambelt with all that load. After all if ambient temps drop below the rating of the coolant for a few days, then starting the engine will stall the belt as the pump will be frozen soilid.
     
  13. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    Well the compromise is for cost and space - chain cam is more expensive to fit to an engine and results in a longer block, because you always need an aux belt as well. The cambelt is already extremely strong and the extra load of a water pump is minimal.

    The water pumps are very reliable - good bearings and metal housings mean that it's extremely rare to see a slippage or jamming up, and if you've let the coolant freeze in the engine through a poor mix it's pretty poor maintenance anyway, especially with modern long-life coolant.
     
    Last edited: 28 Mar 2012
  14. mrlongbeard

    mrlongbeard Multimodder

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    Yep, you can add Vauxhalls to that list too.

    It's quite a common set up, and no real big deal, I only know of one failure of a water pump killing an engine set up this way in all of the people / cars I've known.
    And if you're a DIYer then for less than 50 quid a new pump, tensioner and pulleys isn't such a high price to pay to know everything is tip top.
     
  15. steveo_mcg

    steveo_mcg What's a Dremel?

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    Seized water pump killed the engine in my Vectra...

    I'm still annoyed at that, it was at Vauxuall the week before having the timing belt changed and the water pump was off any way, they noted it was leaking but didn't bother their arse to phone me and say. Instead they wanted to bill me to dismantle the set up and replace it at a later date. Lazy gits.
     
  16. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    I'll have to buy a vauxhall! Timing kit + water pump is about £150 on my 16v Pug.

    Bad luck steveo - not changing them at the specified intervals is usually the cause, did you seek any damages from the garage?
     
  17. steveo_mcg

    steveo_mcg What's a Dremel?

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    Probably should've done but it was a mate doing me a favor getting it booked in, he worked for the same group but at a different franchise.

    The car was dying of terminal neglect any way, she was quite old, but if it was going to go I'd have preferred not to spend £200 on the timing belt. Got £300 for the hulk from another mate of a mate (a mechanic) who dropped a V6 in it, I think he still drives it...
     
  18. mrlongbeard

    mrlongbeard Multimodder

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    It's been a while but yes my price is off :duh:, it looks like the 100 quid mark for a 16v Astra now a days.

    But then I purchased my current car for 2 very specific reasons, 1) it's a diesel and 2) it has a chain so no belt to change every 18 months :rock:
     
  19. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    High miles indeed mrlongbeard!
     

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