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Engine Coolant Sensor problem reveals oil in intercooler

Discussion in 'A4/S4 forum(B5 Chassis)' started by alanmclean1974, Oct 5, 2006.

  1. alanmclean1974
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    alanmclean1974 New Member

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    [Oct 5, 2006]
    For the 1st time since owning it for two years, my 2000 plate 1.8TQ is giving me occasional starting problems. I looked at the forum and it's been suggested that the engine coolant sensor is changed. I've not noticed a problem with the gauge at the dashboard.

    Anyway, I went to Euro Car Parts and they had two different types. So I left it and went to look at the sensor last night, which on my car is on the radiator inlet pipe at the bottom of the radiator. Needless to say as it was getting darker I couldn't get the cable off the sensor. Should it come off when pulling it, or is there a clip underneath to release it?

    To make access easier I took the intercooler to throttle body air hose off, at the intercooler outlet and found some oil there, enough to run into the hose when I pulled it up for a better look.

    I would expect some condensation as the compressed air is cooled but didn't expect oil. Do I have a problem with the turbo?

    Any experts out there that can advise?

    Cheers

    Alan
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  3. JayB5UK
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    JayB5UK Member

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    [Oct 5, 2006]
    I wouldn't really worry mate, on all the turbo cars i've owned there is always some oily residue, or enough to run out of the hose. If it's been like a year or 2 since the hose was last off then really don't worry, it's just that the turbo oil seals are no longer perfect - it'll keep things all lubed up nicely! Unless you are a perfectionist or start seeing clouds of blue smoke on overrun then don't worry about it mate.
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  4. VaulterTim
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    VaulterTim In a world of my own...

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    [Oct 5, 2006]
    Alan,

    Don't worry about a little oil in the intake etc., it is normal since the crankcase breather vents back into the intake after the MAF and gets sucked/blown through the system by the turbo.

    One other thing, there are usually two coolant temp. senders, one for the fan control and one for the dash indication... the one in the radiator hose is for the fans, the other is located at the back of the engine bay in a union on the coolant pipe that runs past the back of the block... it will have a multiplug in the top of it and will be secured with a push-on 'jesus' clip that inserts through two cutouts in the body of the union and locates in two recesses on the body of the sender. I'm guessing (because I have never removed mine) that the other sender is a similar arrangemnt... if I'm wrong I am sure someone will be along to correct me!

    Be careful if you are going to remove either of the senders as they will (obviously) release coolant when removed.

    Have you tried cleaning your MAF sensor to eliminate your starting problems? It is surprising how many niggling faults with these cars can be attributed to the MAF...

    Hope that helps for now...

    Cheers

    T
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  5. alanmclean1974
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    alanmclean1974 New Member

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    [Oct 5, 2006]
    T

    OK thanks for this. Will look for the "other" sender tonight.

    And I'll stop worrying about the oil. Will look for a procedure on cleaning the MAF, aren't they temperamental?

    Cheers

    Alan
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  6. VaulterTim
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    VaulterTim In a world of my own...

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    [Oct 5, 2006]
    Alan,

    Yes MAF's can be temperemental and are especially susceptible to contamination since they are such a delicate instrument. The fact that you have oil in your inlet tract is not, as I previously said, a major problem but if for some reason there is a little more than usual or the MAF has actually never been cleaned before then this could lead to all sorts of problems with erratic signals and readings from it. Cleaning it will, if nothing else, eliminate it as the cause of your problems... you could also try starting the car with the MAF disconnected to see if that makes any difference. If it does then you're onto a winner, if it doesn't then your problem is eleswhere.

    I am by no means saying that the MAF is the root to all problems but it is a starting point since there could be any number of reasons that may cause starting issues... the other thing you obviously will need to do is eliminate the temp. sender from the equation but if the dash indication works correctly then I am sure it will be fine since it is this sender that is used for the dash readout. Either way there is no harm in checking it...

    Let us know what you find.

    Cheers

    Tim
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