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Thread: Coolant and pas issues

  1. #1
    Dorset & Hants Rep pointz's Avatar
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    Coolant and pas issues

    I've built and had my forged ca mapped running 1.4bar low boost and 1.8bar high boost, took it on a trackday and noticed it pushing coolant out the expansion, not massive amounts.

    I have pressure tested each cylinder and with 100+ psi in cylinder 4 the coolant level is rising slowly.

    It is not mixing coolant and oil.

    Anyone experienced this? I have a cometic 1.6mm headgasket fitted and arp head studs and head and block both skimmed to cometics recommended 40 ra finish.

    The gasket was fitted dry with no sealer or copper spray.
    I have since retorqued the head and this has reduced the pressure leak into the coolant.

    I need to remove the head to inspect and also make sure the locating dowels are both inserted, has anyone ever installed a metal headgasket with a sealer if so what sealer?



    I have also fitted an aftermarket pas reservoir fitted on the slam panel (tubbed arches) and this also is pushing fluid out, a fair amount too.
    Originally I figured I overfilled it but once cool the level was well low.

    I am going to try and modify the stock reservoir to fit but are there any other known reasons as to why I am pushing pas fluid out?
    Last edited by pointz; 11-12-2020 at 00:25.

  2. #2
    Guest R3K1355's Avatar
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    Hylomor springs to mind for headgasket sealing. While the head is off get it pressure tested if you didn't already.

    Is the PAS getting hot and belching out? If some maybe you need a little cooler for it?
    or you could try what the MX5 owners do and just run it on minimum, that way it doesn't gush out when it gets hot

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    100NX has a neat little PAS cooler, finned section of tube is about 10cm long, fins 2cm square and overall length about 15cm. Otherwise strip an autobox cooler out of a 2nd hand rad.

    For small head gasket leaks or head cracks try K-seal.

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    Guest Asht_200's Avatar
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    Rich,

    Was this my old engine? Not sure if it has any bearing, but when I had it built, it was supposed to have a wire ringed block


    Sent from my iPhone using Tapatalk Pro

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    Dorset & Hants Rep pointz's Avatar
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    Quote Originally Posted by Asht_200 View Post
    Rich,

    Was this my old engine? Not sure if it has any bearing, but when I had it built, it was supposed to have a wire ringed block


    Sent from my iPhone using Tapatalk Pro
    Its your old head which had a cleaning skim to achieve the correct finish that cometic specify but my block.

    R3k1355 it seems to do it while street driving too.

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    Guest stoofer's Avatar
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    I've used "wellseal" when slapping an engine together (i.e. not skimming any surfaces) to keep the car going whilst properly rebuilding another engine and not had any leaks.

    If you've tubbed the arches, are you running an aftermarket expansion tank and does it have enough room for the... well... expansion that you will get?

  7. #7
    Dorset & Hants Rep pointz's Avatar
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    Quote Originally Posted by stoofer View Post
    I've used "wellseal" when slapping an engine together (i.e. not skimming any surfaces) to keep the car going whilst properly rebuilding another engine and not had any leaks.

    If you've tubbed the arches, are you running an aftermarket expansion tank and does it have enough room for the... well... expansion that you will get?
    Yes as stated aftermarket reservoir which is the same size as stock one.

    I have been looking at well seal

  8. #8
    Dorset & Hants Rep pointz's Avatar
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    Removed the head and looks as though it has blowby on all 4 at some point.

    Opinions?

    Bad gasket, headlift, stud torque.......

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  9. #9
    Dorset & Hants Rep pointz's Avatar
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    Any opinions on this?

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    Go with a fibre gasket ?

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    Is it worth emailing some pictures over to Cometic and see what they say?
    If you've used ARP head studs, I've heard of people having issues when using the ARP torque specs on SRs. I've seen advice from someone to start of with 30 then 60ftlbs following the nissan torturing pattern, then back them all of loose and do 30, 60 and 75-80ftlbs but you have to use their moly lube.

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    Guest R3K1355's Avatar
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    Quote Originally Posted by Mike41288 View Post
    Is it worth emailing some pictures over to Cometic and see what they say?
    Would imagine they'll say the same old thing, surface issues, blame the machining or assembly process, didn't follow our recomendations, blah blah blah.
    The gaskets are notorious for this problem.

    Quote Originally Posted by Jonny Wilkinson View Post
    Go with a fibre gasket ?
    This, go with a stock Nissan gasket.


    Quote Originally Posted by pointz View Post
    R3k1355 it seems to do it while street driving too.
    Maybe go with the standard res and see if that helps?

    Could the bearings in the PAS pump be shagged or something? Gotta be 25+ years old.

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    How much did they take off the faces and which thickness cometic gasket is it? A standard fibre gasket may not be thick enough.

  14. #14
    Dorset & Hants Rep pointz's Avatar
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    Quote Originally Posted by Jonny Wilkinson View Post
    How much did they take off the faces and which thickness cometic gasket is it? A standard fibre gasket may not be thick enough.
    I'm running a 1.6mm cometic so can't go back to oem unfortunately

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