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S4 Oil Temp high

Discussion in 'A4/S4 forum(B5 Chassis)' started by EnzoS4, Aug 9, 2008.

  1. EnzoS4
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    EnzoS4 Member

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    this is a bit long, but we need help...

    the oil temp seems high around 110 without driving hard or going over 3000 revs. normally for me the temp is around 90. this happen after a service from Audi who fixed it by replacing the oil. my next service was with non-audi garage and it happened again - oil temp between 110-120. I had the cam-belt, water pump and all the normal bits replaced and still oil temp running high around 110.

    normally with the oil temp at 90, it would rise to about 110 if I pushed it but I am not keen to push it at the moment. in fact I am not driving it.

    work so far:
    7 months ago
    --- Service - oil temp between 110-120
    --- replace oil - oil temp normal
    6 months ago
    --- replaced MAF - oil temp normal
    1 month ago
    --- Full service - oil temp between 110-120
    --- cam-belt changed / water pump - oil temp between 110-120
    --- replaced oil with Shell Oil - oil temp between 110-120
    --- replaced oil with VW Quantum Oil - oil temp between 110-120
    fortnight ago
    --- replaced the oil with Shell Ultra - oil temp around 110
    last week
    --- replaced water temp sensor - oil temp around 110
    --- replaced oil sensor - oil temp around 110 (dose anyone know how the oil temp is worked out..? I've been told the original S4 had the temp taken from the oil temp sensor, the facelift dosen't have this sensor just an oil sensor that the ECU uses to calculated the oil temp with other sensors, if so which ones..?) is this right...?

    --- replaced the water pump - oil temp around 110

    another thing I've noticed, when at the petrol station the water temp would normally be at 90.? (well 12 o'clock) but sinse this problem after I paid for the petrol adn returned to the car the water temp is near 100. I've never seen this go above 90 (12 o'clock).



    I have Audi service the S4 every 6 months and a full long life service every year.

    I've searched here and on RS246 and couldn't see any issues like this..?

    I use the misses little Astra at the moment which is only a few years old and great on fuel but so, so powerless... I had Mr DTi cut me up last week and had to let me go... HELP ME...!!!


    Audi are now not sure what to do next and now saying this is normal, but will look at this further if I want. The only other bits I can think of is the ECU or dash its self but both expensive to replace and not sure how to test them. Audi said these would show error codes if there was an issue with them...?

    Its got to be somthing the service causes... but what and why...?

    any ideas...?
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  2. bahnstorm.net
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    bahnstorm.net Member

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    could be numerous things...the spell of hot weather will cause it to run hotter,if the car is running very lean oil will get heated more,water cooled oil cooler may have seen better days,also low oil pressure will allow the oil to heat more due to slower circulation,adding an air cooled oil cooler will help if there is nothing wrong,mine often reaches 110 still on standard watercooled oil cooler
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  3. EnzoS4
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    EnzoS4 Member

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    thanks bahnstorm, didn't know these were water cooled oil coolers...

    mine still or did sit at around 90 in hot weather unless I was pushing it, other than that it would be around 90...

    in one day it was running OK, had a service then it run hot... I will get Audi to check them.

    any other suggestions..?
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  4. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    Thermostat i would think is the only thing i can think of ,assuming the water temp is also playing up.

    Otherwise
    I wonder if the oil temp sender is faulty? Cannot be much to swap it out
    #4
  5. EnzoS4
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    EnzoS4 Member

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    thanks for the reply, good point I will add this to the list to get Audi to confirm this is OK

    but unless I am getting very unluckly the thermostat was replace when the cam belt / water pump was done and again when the water pump was replaced recently.
    #5
  6. Blue_Thunder
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    Blue_Thunder Active Member

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    First thoughts are the oil temp sender, but as Bahnstorm has suggested, it may be running lean.

    Have you got Vagcom? I'd check the long term fuel trims in Block 32 to see if the ECU is having to alter the fuelling. Imagine Audi would have checked for any obvious fault codes (ie: EGT sensor failure, etc), but you never know.
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  7. EnzoS4
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    EnzoS4 Member

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    ...UPDATE....

    I passed on the suggestion from Byzan A4 and Blue_Thunder to Audi and was told all was running well, no errors and themostat OK. thanks anyway guys...

    Audi did a check on the dash cluster again and said the oil gauge was a bit slow moving when compared to the other gauges. £400+ to replace the cluster - NOP.

    Drove the car to work and back and still seems to be hi around 110. as I was going up the driveway the dash displayed the brake error (O). This is all I need - Front disc and pads replace.

    Audi check the oil temp and it is what he guage says, the next suggestion was to replace the sump sensor which was another load of oil. this was done and oil temp now around 105. to me this still seems high and thats driving 15 mins on b roads behind a trackor this morning.

    Audi Technical have said that the temp for the S4 should be between normal driving 80 and 120 push hard. mine still seems high at 105, normally for me it around 90.

    I so much enjoy this car but I think we have reached the end of the line, so maybe its time to pass the S4 on, unless anyone has any other suggestions...
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  8. Blue_Thunder
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    Blue_Thunder Active Member

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    Where are you based? Think you are wasting your time with Audi, you should take it to a specialist.

    The only other thing I can think is that there is a problem with the oil/water heat exchanger in the radiator. Perhaps a blockage?

    The fact the oil temp has slightly dropped after an oil change does perhaps point towards some kind of blockage.
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  9. EnzoS4
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    EnzoS4 Member

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    Thanks, I had this at a specialist originally who serviced the S4 and got stuck, do you have any suggestions..?

    How do you find a blockage...? I did raised this with Audi and it was suggested that blockage would cause low oil presure which the diag isn't detecting, or is it high presure, either way the diags show presure OK.

    its the oposite, the oil was around 90, but just after a full service (oil change)the temp went to 120..? various sensors later and the reading has come down to 105...?
    #9
  10. Blue_Thunder
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    Blue_Thunder Active Member

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    When did you last change your oil filter?

    Where are you based? Maybe someone can recommend another specialist that's not too far away.
    #10
  11. EnzoS4
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    EnzoS4 Member

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    twice in the last 30ish days with 5 oil changes...

    buckinghamshire.
    #11
  12. Blue_Thunder
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    Blue_Thunder Active Member

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    You're spoilt for choice down there!

    MRC or APS are both highly regarded. I've not used APS personally, but have used MRC on a number of occasions and they are excellent.

    Don't think there's anyone in the UK who knows more about the 2.7T than Doug@MRC... he's certainly seen enough of them! Give them a call.
    #12
  13. EnzoS4
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    EnzoS4 Member

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    APS are great and I've always used them but there stuck on this. I'll give MRC a call and let you know
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  14. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    i think you need to find out if the sensor is lying or not

    If the stock sensor is in the sump as you suggest (i find this unusual but anyway), get a temp probe in the sump with the engine hot (but off) and see if it matches (most emissions testing equipment have oil temp testing probes)

    if its not in the sump then remove the audi sensor and replace it with an aftermarket one and connect it to a stand alone guage

    if the oil IS hotter than it should be then you need to look at the oil cooler system imo
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  15. Blue_Thunder
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    Blue_Thunder Active Member

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    That certainly would explain why your water temps are raising slightly when you've left the engine to sit for a while.

    Honestly mate, get it over to MRC. They won't let you down!
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  16. EnzoS4
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    EnzoS4 Member

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    Audi have check the oil temp against the oil guage which is reading correct. I do agree but not sure how to check for blockage, maybe replace the oil rads..

    just sent MRC an email, will call them tomorrow to see about booking the S4 in.
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  17. Blue_Thunder
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    Blue_Thunder Active Member

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    There isn't an oil radiator on the S4 as such. The oil gets routed through oil/water heat exchanger and the water in the radiator cools it.

    You could think about fitting an RS4 (or aftermarket such as Mocal - like i'm doing) oil cooler, but there is obviously an underlying problem which needs to be addressed.

    Let us know how you get on.
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  18. Siena
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    Siena Active Member

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    The sensor in the sump is NOT an oil temperature sensor!

    It's a sensor to monitor oil quality, and supplies data for oil change / service inspection.
    #18
  19. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    mate knowing main dealers, audi's "checking the temp" would involve sticking a diag computer on it and reading off what the ecu thinks the oil temp is.

    If the sensor is lying or there is some wiring fault then your not going to know any different as the two readings will match, all thats proved is that the instrument cluster is accurately representing the data its being fed

    The fact they changed that oil sensor in the sump that doesnt even check the temp kinda shows how competent they are.

    get a real mechanical reading of the oil temperature in the sump once the engines fully up to temp and compare this with the readings the ecu/dash is giving. If they match, i'd be looking at the oil/water heat exchanger which might be blocked internally or something, if they dont then the oil temp sensor or its associated wiring would be my guess.
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  20. EnzoS4
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    EnzoS4 Member

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    Update

    2 weeks ago took it to MRC and after a few test drives it was suggested that the heat exchanger may be blocked, well done ARAGORN. anyway got it booked in and today it was swapped out, including the oil again. more ££££'s lighter and the problem is............... not fixed, credit to MRC for the friendly service. I think the problem is almost exhausted, the oil temp still hits 110 but stays there even after a little hard drive.

    next step...? not at MRC but I am so p!$$ed off with this, I think its time for the white towl and sell it. looking at S4 prices gaps..? - low £4-5kish or £8-9kish.
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  21. Siena
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    Siena Active Member

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    Enzo, where abouts in the country are you?
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  22. Blue_Thunder
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    Blue_Thunder Active Member

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    Have you spoken to MRC about it?

    They've done work for me in the past which didn't solve the problem(although the conclusion of the problem they came to was understandable). I told them the problem still existed and they worked on the car (without charge) until they figured out and sorted what the problem was.

    I can't fault them.
    #22
  23. EnzoS4
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    EnzoS4 Member

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    Siena - Buckinghamshire area

    Blue Thunder - MRC have been working on it, and also not sure what is causing it. and yep your footer says it all.... but for me I think that's because I want everything near spot on.

    one thing I found is the RS4 have an additional oil cooler rad, just wondering if this can be fitted..? that would cool the oil but not sure good idea as problem still exists..

    next weekend one final clean and a few pics for the sale...
    #23
  24. Fraser
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    Fraser Member

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    a custom oil cooler is probably cheaper and easier to fit - MRC do one. the RS4 ones can crack and you get coolant and oil mixing - not good.
    #24
  25. Blue_Thunder
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    Blue_Thunder Active Member

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    I've got a 25 row Mocal oil cooler for sale - £50
    #25
  26. EnzoS4
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    EnzoS4 Member

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    still not sure if oil cooler is best way to go as oil is getting hot for a reason..?

    but for £50 I could always pass this on with the car, do you have the pipes and connectors..? take it the coolers been used, what is the condition.? and thanks for the offer.
    #26
  27. Blue_Thunder
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    Blue_Thunder Active Member

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    Sorry, doesn't include any pipework, just the cooler. It's used, but looks virtually new.
    #27
  28. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Enzo You've not actually said whether you've had the temp checked by an external source.

    From what i can gather from this thread the actual oil temperature sensor hasnt been changed as you said the dealer only changed a sensor in the sump...

    It seems to me that until you get another independent gauge hooked up to the car with its own sensor and find out whats really going on then your just running in circles

    You need to find out if its the guage thats lying (perhaps due to the sensor itself or some wiring issue) or if the engine IS actually running hot.

    If it IS running hot and the oil cooler is fine then i think it can only really be a fuelling/ignition issue thats making the engine/turbo run hotter than it should be

    If its not running hot then either the oil temp sensor (which is mounted on the oil cooler afaik) is faulty or the wiring to it has some problems.
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  29. EnzoS4
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    EnzoS4 Member

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    - I've had APS, Audi and MRC all investigate the issue.

    - I had all water, oil and air sensors replaced about 7 in total.

    - Audi and MRC said the stats show the car is running perfect except for the oil temp.?

    - I agree, I've asked all the garages to check the oil temp to see if it is actually hot, but question is how to do this quickly with out affecting the results, take the oil out of the car will cool it down quickly.

    - good point but the sensor on both manfolds is showing the temp low/normal, if you can call manfold very high temps normal... this shows the turbos not running hot.

    - not sure if the S4 has this sensor but again agree could this be a wireing issue, if so how could we check it.

    - I am currently looking for an old dash insert to check against mine to see if this is faulty as this is about the only thing we haven't fully tested. but not found any yet.


    - Thanks ARAGORN for your comments and THANKS to all in this thread for your suggestion, please keep them coming as this is such a clean original car that I would HATE to sell, but I just can't afford to keep paying out. I like my cars to all be in top working order, the slightest issue I would want fixed...
    #29
  30. GSB1
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    GSB1 Member

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    oops, should have read the full thread first
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  31. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    what i would do, is get an aftermarket oil temperature guage and sender. The type chavboys tend to screw into their dashboards will do as long as its half decent.

    Remove the original audi sensor, and put the guages sensor in its place. Hook the guage up and run some temporary wiring into the cabin for it. Even just having the guage laying on the seat or infront of the ashtray will do for testing.

    Looking at vagcat the original sensor appears to be screwed into the front of the block, possibly behind the viscous fan, although the image doesnt show an S4 lump so it might be positioned somewhere else, the item description does say its for the AGB engine though so i presume it is the right think (item 4, p/n 049919563B):

    http://www.vagcat.com/epc/cat/au/A4Q/2000/224/57/2825063/

    Take the car out for a spin and see what this guage tells you compared to what the audi guage has been reading. Hopefully it will tell you that either everythings fine mechanically and its an electrical gremlin your chasing, or the engine is actually running hot. Which should give you an idea of where to go next.
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  32. Blue_Thunder
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    Blue_Thunder Active Member

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    The fact that the EGT's are normal and also that the coolant temps aren't rising past 90 when driving does suggest that the engine isn't running hotter than 'normal', but if the oil temp sender has been changed then that sounds very odd.

    Have you tried doing an instrument cluster check on Vagcom?
    #32
  33. EnzoS4
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    EnzoS4 Member

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    aragon - I am looking at getting an oil guage and this adaptor - thanks for the part no.

    blue thunder - yep both Audi and MRC said all is OK on the cluster. I am currently looking on ebay for a cheap one just to confirm... none at the moment, unless someone has one I can borrow.


    I do wonder as aragorn said is it a gremlin I am chasing. coming home yesterday gone 8pm and the temp never went over 100...? doing 50 or less most of the way in 6th, but soon as I over took a car, (speed about 60ish of course) oil went to 110...? going to work this morning did the same 50 or less most of the way and temp was at 110...? the cooler air at night is keeping it cool.? not sure what this is telling me but maybe the guage is OK..

    next step get the guage or cluster and confirm oil temp.

    I know this is going on but thanks for the replies.
    #33
  34. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    The thing that makes me thing it has to be either a faulty sender or wiring is this:

    You have a brand new oil cooler, which would imply that the temperature of the oil is being correctly regulated by the engine coolant. The engine coolant is at normal temp, which means the cooling system is working properly, so its only fair to assume that its cooling the oil properly.

    The engine is otherwise running normally, therefore its probably safe to assume that the engine is not generating too much heat in its oil for the cooler to be overwhelmed, especially as if it was running hot enough to overwhelm the oil cooler i'd expect the main cooling system to be showing signs of struggling too as the additional heat being dumped into the oil would also be getting dumped into the coolant.

    The ECU and gauge cluster agree so its not a guage issue, the only thing left is either the actual oil sender, or the wiring to it.

    A nice idea might be to get VAGCOM on it while your driving and leave it logging. If it was a sporadic wiring issue, i'd expect to see the readings jumping around a bit instead of smoothly climbing between the values. That way instead of looking at the relatively crude guage readout you can see exactly what the ECU thinks the oil temp is doing as you drive along and analyse it afterwards.
    #34
  35. EnzoS4
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    EnzoS4 Member

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    well this could be the end of the story....

    replaced the ecu and dash with temp ones and no difference, temp still higher than normal so as aragorn suggest its not the gauges, its also not the ecu. the temp ecu was setup with stage 1 which turned the S4 into a completly different car. I would love to get me one of these upgrades and recommend to anyone with an S4 to test it out, contact MRC, what a difference... reason for using stage 1 ecu was to see if anything would be highlighted more.... and nothing was, everything that vag-com was showing was spot on even with stage 1, if you didn't see the oil temp gauage, vag-com was showing no issues at all...?

    took the S4 on the motorway and at 70mph for about 20 miles the temp stayed at 110 (car with my ecu and gauges).

    APS failed, Audi had no luck, and MRC were great but not sure what to do next and said everything you think of, vag-com is showing as spot on and theres no ticks, wines, taps... nothing.. everything seems fine.

    issue caused just by doing a service...? (plugs, filters, oil..)... this is just crazy


    MRC did a lot of diag testing and I don't think there is anything else that can tested on the car...?


    thanks all for your help and suggestions on this one... one last question - SELL, BREAK, KEEP...?
    #35
  36. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    You still havent said if you;ve actually replaced the oil temp sender in the front of the block nor tried it with a standalone guage.

    With what you've told me, i dont think theres anything wrong with the car mechanically. Its either a sender or wiring fault.

    http://www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=MCYCLE&pcode=R/PRTEOT150

    go buy something like that and see what it says. My bet is it'll sit at 90-100c quite happily.
    #36
  37. EnzoS4
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    EnzoS4 Member

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    yes temp sender has been changed , didn't try a standalone guage but did switch the complete set of gauges out with a temp set which provided the same readings...

    I did ask MRC about doing this but seemed like an awked job for them, where would this connect / plug into.? if easy enough I'll give it ago. fingers crossed your right, which would then mean its the wiring...?
    #37
  38. Blue_Thunder
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    Blue_Thunder Active Member

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    Keep it!!!

    If MRC and APS have exhausted all their avenues of investigation, it's probably safe to say there isn't a serious problem with your car.

    Sounds like you should just pass it off as a gremlin and enjoy... and remap... and enjoy more!

    You need to ask yourself these questions:

    1) How much could you sell it for if you were to put it on the market tomorrow?
    2) Would anyone be willing to pay full whack for a car which showed high oil temps?
    3) If it did go bang in x months time, how much could you sell it for either whole or in parts?
    4) What would you replace it with?

    Question 3) might seem odd, but with the prices dropping out of the market recently, S4's aren't worth that much less in parts as they are as a whole car. If the difference isn't going to be that much, it's worth risking that on a few months/years more extreme driving pleasure!
    #38
  39. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    ive not looked too closely at the layout of the S4 motor, but the general idea is you tap it into one of the oil galleries. Usually there are spare tappings on the oil cooler or you can T-Piece off the oil pressure switch or the existing temperature sensor.

    The other approach would be to T it into the oil supply feed to one of the turbos.
    #39
  40. EnzoS4
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    EnzoS4 Member

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    well just an update for the record...

    I still have the car and the temp is running around 100c, maybe because the weather is a lot cooler but still coming home to night it didn't reach 100c.

    now I am confused, and I beat the next service will knock this upto 120c again, which is in Mar/Apr 09 (every six months)...

    i think the issue could be a silly thing I did a while ago... I was running low on oil and put in some GTX magnetec, which I've now been told can cause the oil to block or clog oil channels... has anyone flushed the engine before and with what, the only proper way I can think of is to pull the heads of and clean all the oil channels and clean / replace the oil pipes...
    #40

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