Sunday drive travails: tips for diagnosis please
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  1. #1
    Fellow Frogger!
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    Default Sunday drive travails: tips for diagnosis please

    Fun and games today on a drive of th D Special into regional Victoria. All going well until on the way home, 120km short of Mebourne, when 10 year old son draws driver's attention to "clacking" sound from engine bay. Increasingly worried driver pulls over, lifts bonnet and met by definite clack (and breathing) sound.

    Initially I was concerned about the water pump, especially when some coolant emeged on the pavement underneath. My other concern was HP pump. Or maybe a head gasket, I began to think when a couple of friendly locals starting offering their advice (we had stopped outside the pub).

    It soon transpired, however, that there had been no loss of either coolant (my car tends to lose a little from the overflow after turning the engine off from a run) or LHM. The oil of the dipstick looked fine. And when I listened, it seems that I may have developed a leak at the exhaust manifold. The sond has that "breathy" quality about it, and certainly much more pronounced at idle or under acceleratin, and not on deceleration.

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    I took a gamble and nursed the car to my sister's property some 30km away. Certainly there seems to be less power, but not any apparent missing/knocking and no overheating or further loss of coolant. I have played it on the safeside and borrowed her VW Eos (now there's quite a nippy little beast) and left the D Special to xcontemplate what to do. I have no intention of stupidly cooking the engine or further wrecking a water pump etc.

    Any ideas from this rather cursory description about what to do next?

    AM

  2. #2
    Contented Peugeot Driver addo's Avatar
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    Compression test?

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    Too many posts! JohnW's Avatar
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    Exhaust manifold leak at gasket? It can be a very sharp sound.

    I'd do the compression test cold then start the car and, while it is cold and you won't burn yourself, listen very carefully around the manifold.

    Is it really less power or imagination? If it is less power, I'd start to be worried. Are all the spark plugs tight and/or in their holes?

    Good luck.
    JohnW

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    Fellow Frogger! marc61's Avatar
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    The exhaust manifold stud that's nearest the water pump end of the engine can work loose. Suggest checking tightness of each nut on exhaust manifold. If the stud is loose, or the thread in the head has gone, it's a case of fitting a helicoil or making a stepped stud and tapping the head accordingly. I did the latter when it happened to my Safari, no problems since.

    Cheers

    Marc
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    Fellow Frogger!
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    Thanks. You're right. Follow the basic diagnostics. Next task when I get back to central Victoria to retrieve the car.

    On reflection, I am reasonably confident it is a blown exhaust manifold gasket. Further examination will reveal all, hopefully.

    Trip was otherwise fun. 10 year old boys love these cars.

    Sunday drive travails: tips for diagnosis please-yarck.jpg
    Last edited by ajaxvte; 13th October 2014 at 10:32 AM.

  6. #6
    Fellow Frogger! ScotFrog's Avatar
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    Quote Originally Posted by JohnW View Post
    Exhaust manifold leak at gasket? It can be a very sharp sound.

    I'd do the compression test cold then start the car and, while it is cold and you won't burn yourself, listen very carefully around the manifold.

    Is it really less power or imagination? If it is less power, I'd start to be worried. Are all the spark plugs tight and/or in their holes?

    Good luck.
    I had almost the identical symptoms which turned out to be number 3 spark plug just slightly loose.

    SF

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    BVH Roger Wilkinson's Avatar
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    Exhaust leaks can cause power loss. I once had the flexible pipe on a DSuper let go on the way down the Crown Range road in New Zealand. The car became as gutless as a 2CV. Temporary repair with exhaust putty, a fruit tin and some hose clamps lasted for months before I got around to fitting a new flexible pipe.

    Roger

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    JBN
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    I blew a piston ring in a 2CV and it was as gutless as..as...as... a donkey.

    It is very difficult to compare a damaged 2CV engine to anything.

    John
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  9. #9
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    Finally got back to the car today. Compression test good. No. 2 plug was not tight. And definitely an exhaust manifold leak. Got it home without any problems. Repairs next week...

  10. #10
    Too many posts! JohnW's Avatar
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    Quote Originally Posted by ajaxvte View Post
    Finally got back to the car today. Compression test good. No. 2 plug was not tight. And definitely an exhaust manifold leak. Got it home without any problems. Repairs next week...
    Excellent! You were right to play the cautious driver though.

    Cheers
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

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