1.8T seems to be overheating for no real reason...

Discussion in '1.8 & 1.8T' started by HidRo, Sep 2, 2017.

  1. HidRo Forum Member

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    Nige, that is about right.

    So, today we did some more tests.

    We added the old fan (now making it 2 fans that take about the entire radiator. BTW, the old fan is a lot better than the new Mishimoto one :S) and went for a drive.

    Started driving, and it took the expected amount of time to reach the 80C. Then, slowly up to 89/90C.
    Let the car idle, and it went as high as 96, and back down to 91C.
    Took off again and if I kept my pedal to maintain the speed(120/140kmh), it will be around 90C. If I coast on a hill, it will come down to 86C.

    Some pulls, at 1.5bar will not raise the temp much (91C give or take).
    Park the car and let it idle, it will raise again up to 96C and back down to 93C.

    Oil was never over 80C (after the hard pulls) and 74C while driving normally.

    Night out is 20C.

    The thing is, not sure what happened to make it need the 2 fans instead of 1 to get the same results...

    On another note, I used to use BP Visco 7000 5-40 and changed to the LiquiMoli 10-60W "racing" oil.
    It seems the lifters are way louder... Some underlying issue or just the oil.

    Pffffff I'm feeling this is not going in the right direction.

    EDIT: forgot to mention. Both fans at full speed will never turn off at idle. I believe it's supposed to turn off right? And this is after driving normally and temps being at around 90C. Not pushing it hard.
     
    Last edited: Sep 14, 2017
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    they should eventually cut out yes, the OEM switch is set to cut in at 95 degrees radiator temp then switch off again at 84 degrees.

    looking at your picture the header tank position looks ok. the thin hose should go to the small outlet on the top hose plastic fitting thing, bottom hose goes on the metal coolant pipe round the engine. as long as yours is plumbed like that you should be fine, the systems self-bleed pretty well VW dont even specify a bleed method just fill it up, put the cap on then once its got hot enough to open the stat shut it off then fill it up once required.
     
  3. HidRo Forum Member

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    Yeah, it is connected that way.
    When the car is running, we can open the header tank cap, it will be OK, so no excessive pressure (head gasket leak) and we can see it's flowing from the small hose. All seems to be OK.
    The switch I have is a 87-82 IIRC, but the temp will never go below 91C. So I'm guessing the engine might be running a bit hotter than it should? What would cause that?
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    could just be your thermoswitch is too cold then? the dash reading will always be a bit higher than the temps in the radiator as its on the hot side of the engine on the top hose. the thermoswitch is all the way over on the cold outlet end of the radiator so any coolant that makes it there will already have been cooled by the rad/fan, if you get me.
     
  5. HidRo Forum Member

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    But wouldn't that make it worse, as in the water always being a couple degrees higher, therefore not cooling enough?
    I have another termo switch which could be tested. I'll give that a go.
    I do understand the temp difference, but we measure it also with a digital pyrometer.
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    what I'm saying is your coolant is probably the correct temperature, its just your fan thermoswitch is set too cold. so even with the fans at full speed they cant get the temps low enough to switch off the lower temp thermoswitch if your car is just sat idling if you get me. I would try a factory 95-84 thermoswitch and see how you go

    coolant temps between 91-96 are absolutely fine and your oil temps are ok as well, maybe even a little cooler than I would like to see once fully warm (do you have an external oil cooler?)
     
  7. Nightroamer Forum Member

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    I would always assume a running temp of around 100C to be normal on a pressurised system and my oil runs between 80C and 90C most of the time (ABF)


    Sent from my iPhone using Tapatalk
     
  8. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Ah...that would be much different root cause to what I was suggesting then.
    More like some circumstance has shifted at an instant.
     
  9. Nige

    Nige Paid Member Paid Member

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    I'm not sure 10w60 is the best oil for your application. I only run 10w50 and that is for an out and out track car that's always thrashed.

    Anyway, if 2 fans are working, that's fine on the road but the air flow should be sufficient on track that the fan isn't needed. Mine never runs on circuit
     
  10. HidRo Forum Member

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    rubjonny, I don't run a oil cooler, and I don't remember ever seeing the oil temp going high as 130C or something like I read someone saying it was normal on the track (for a short period of time).
    I'll try the other thermo switch for sure.

    Nige, do you know from the top of your head (or have a log hanging around to show) the temperatures that you usually run?
    A max of what temperature is the foot off threshold?
    I know that you have an aluminum radiator, which could make some difference of course.

    I think I might try the BP Visco 7000 again, just to make sure the engine is quieter. It sounds a lot worse...
    Why wouldn't a 10-60 be a good oil for my application? I always assumed the best ever would be to have it higher as possible, ie 60. Advertisement works, right? [:D]

    Well, if it seems that it's working OK with these temps, I might just be overthinking it.
    We will do some more tests next Monday, driving on a hill climb, so I force the car to be pulling hard (uphill) without racing a lot to get a ticket or crash [:D]
     
  11. rubjonny

    rubjonny Administrator Staff Member Admin

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    maybe double check the part number on your oil sensor to make sure its correct for your dash :)
     
  12. HidRo Forum Member

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    Hummm, is there a list? :p
    Now that you mention it, the oil sensor is the one from the KR I believe.
    The Cluster is from a SEAT GTI 16V (ABF engine).
    Maybe that is not correct?
    Also, this sensor is next to the oil filter, not the head.
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    ah, the SEAT ABF uses the mk3 oil sender 1H0919563, I'm pretty sure they are slightly different to the mk2 golf one. in the filter housing is where it should be on the mk3/seat :)
     
  14. Nige

    Nige Paid Member Paid Member

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    You don't run an Oil cooler on a tracked 1.8t? I'm stunned.

    My oil is usually 120 to 130 degrees. When following close to another car at the ring it's between 130 and 140.
    I've had it at 150 to 160 and haven't lifted off. Oil pressure good, bearings showed no excessive wear when checked and when tested, the oil results were positive with no cause for concern.

    Still not a range I would be comfortable running for a time though.

    Water sits at 87 to 89.
     
  15. HidRo Forum Member

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    Well, could very well be that the issue is with the sensor not showing the correct information, that I never thought of. I'm now buying a sensor and it should scare me at the track [emoji3] I believe I'll not have the water at those temps at the track as it was not like that during the night...
    I'll consider the oil cooler. I have a friend that has a S2 one for free. If it's in good condition I might take that offer.

    Sent from my Redmi Pro using Tapatalk
     
  16. HidRo Forum Member

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    We checked compression on all cylinders, and it was 14bar on every single one of them. It's all good from there, so no head-gasket issues. Also, checked with a endoscopic cam, and the cylinders and walls were good!
    Tonight I'll check the temps while doing a hill drive to see how it behaves driving a bit harder.
     
  17. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    On road, you are unlikely to have the fans running at motorway cruise speeds at part to mid load. Apart from city traffic, you can have them turn on on a motorway/expressway or autobahn, if you are are at full load for an extended period of time or if at high part load in ambients over 27 deg C.
    If the hypocritical car I painted was then taken on a track, the fans are likely to activate here you are constantly loading up the engine in slow bends.
    I have been fortunate to observe this with 16v, 8v, 20v and VR6 vehicles.
     
  18. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    John does have a point on oil temp sensor resolution between the marks of Golf.

    Mk2 Golf MFA clusters both Motometer and VDO use a 0-180c temp sensor as shown below.

    MK2OilTempsensor.jpg

    Seat 6K Ibiza/Cordoba Passat 3A and the MK3 Golf clusters use 0-150deg C oil temp sensors.

    ABF_oiltempsensor.JPG

    While this correction to the matching sender only helps to make reporting here more accurate, that action does not explain the sudden change in temperatures you observed though.
     
    Nige likes this.
  19. HidRo Forum Member

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    So, I changed the oil temp sensor, for the ABF one, and it showed 80C maximum while going for the hill drive. (that PN 1H0919563).
    It was a 2nd 3rd drive, boosting 1.5bar, uphill, so no fancy speed (maybe about 100kmh max at some points) but building up power on and off the gas pedal, braking, etc.
    The temperature was always between 82 and 89.
    I then coasted to a place where I stopped the car letting it idle. It was at 90C. In 60s, it went up to 98C (which I believe it's OK) but then in 3.30m, it went from 98C to 95C (which I believe it's not that OK).
    Still, driving it seems to be pretty much OK, just not idling.
    Night out was around 17C, and intake temp was max 24C (except when it was idling that raised up to 32C, which is expected).
    MSLog.jpg
    I believe everything it ok enough to go to the trackday I'll have on the 1st October and test a bit more over there.

    Pic of the log
     
    Last edited: Sep 19, 2017
  20. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Complete the experiment. Swap the sensor back to the "KR" part and repeat the drive, logging the same data items and see what the delta is your reported oil temperature.
    This should align with what you originally reported. From there we can close off the differences in reported oil temp readings.
    Still does not answer suddenly reporting overheating, but rules that out as a factor.
     

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