Fiat 2.8 JTD overheating?

Discussion in 'Fiat' started by mustaphapint, Nov 21, 2015.

  1. mustaphapint

    mustaphapint Funster

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    Ever since we bought our Hymer B644 I've thought it was running cool. The temperature gauge in the dash never goes above a reading of 60 and the in cab heating has never seemed particularly warm, even on quite long runs. I had it in mind that the thermostat may not be working properly.
    That all changed this evening on our way back from Cornwall. I was driving a bit more spiritedly than I have done before and there was a lot of uphill work. The temperature gauge still didn't go over 60 but we noticed that the cab heating was working a lot better, in fact it was getting a bit too warm. Then the high temperature warning light came on. By this time we were just coming up to some services on the M5 so I pulled in. The radiator header tank was still full and the radiator hoses were hot but the top of the radiator was cold to touch and the fans were not running. We left it to cool down for a while then set off again. I kept the speed below 50 and we covered another 70 miles or so without problem and then the warning light came on again after I let the speed creep up a bit. I slowed down and it went off straight away and stayed off for the remaining 50 miles home.
    Where is the sensor for the temperature gauge?
    I haven't had a proper look yet as it was dark when all this started but we're quite pleased to get home without any further problems.
    I'm thinking the radiator may perhaps be blocked and I'm hoping it can be flushed out.
     
  2. tonyidle

    tonyidle Funster

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    It could be a blocked radiator but it could also be that your faulty thermostat has blocked off the flow. I'd change the thermostat & look very closely at the old one before doing anything more expensive.
     
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  3. DP_JAY

    DP_JAY Funster Life Member

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    Could also be the water pump
    A friend recently had one where the impeller had parted from the shaft. Only took the pump out after replacing the thermostat & flushing the radiator as he was reluctant to disturb the timing belt. Be aware if the water pump fails it can take the timing belt out too.
     
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  4. CHRI$

    CHRI$ Funster

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    same as?i had a vectra that was over heating and changed the thermostat and it made no difference,engine hot,rad cold.on further investigation found that the impeller had indeed parted from the shaft on the water pump and was not pumping coolant around the engine .
     
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  5. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    "Be aware if the water pump fails it can take the timing belt out too."

    Not very likely on a 2.8 as the water pump is not driven by the cambelt even though the cambelt has to be removed to change the water pump.

    D.
     
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  6. gus-lopez

    gus-lopez Funster

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    & check that the fans come on as the temp. rises.
     
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  7. Stealaway

    Stealaway Funster

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  8. Badknee

    Badknee Funster

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    It's the cool rad at the top that's a telltale, there's not much water getting through. The reason for a cool reading is that the sensor may be in the top of the rad, as may be the fan switch. They both think everything's ok. Faulty stats as far as I am aware 'fault' open or used too so it should be passing water (Ooooer Mrs ;)) needs checking out though. Good luck (y)
     
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  9. pappajohn

    pappajohn Funster Life Member

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    Chances are the fan switch is in the radiator side box and not on the engine so if water isnt passing through the rad, which seems to be the case, the fans will never work.
    The temp sensor will be on the engine block which is why that illuminates.
     
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  10. emmitdb

    emmitdb Funster

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    We have a water related problem on our Hobby with the same engine.
    On our recent Continental jaunt I noticed that the water temp. gauge automatically goes to the half way mark immediately on turning on the ignition and, regardless of our travels, never moves a jot until the engine is switched off.
    Fortunately we didn't have any associated problems and it's a job now that we're back home.
     
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  11. teensvan99

    teensvan99 Funster

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    Emmitdb.
    Had this problem with our 2.8 jtd. Common fault. I used to remove all 7.5amp fuses one at a time and replace. Gauge would now work fine
     
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  12. denisejoe

    denisejoe Funster

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    But the cambelt failing can take out the water pump

    Joe
     
  13. tonyidle

    tonyidle Funster

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    :D:D:D:D
     
  14. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Not very likely but it does make sense to change the water pump when changing the cambelt simply because if the pump fails later then the belt has to be removed to replace it.

    D.
     
  15. Dave and Ginny

    Dave and Ginny Funster

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    If you do take a look at the thermostat it's worth putting it in an old saucepan of water and bringing it up to the boil on the hob. Can't quote temps, but it should not start to open until almost at boiling point.
     
  16. denisejoe

    denisejoe Funster

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    It did when our cambelt tensioner went earlier this year and we'd only had it replaced the previous year.
     
  17. mustaphapint

    mustaphapint Funster

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    I was told the cambelt was changed about 7,000 miles ago. I don't know about the water pump. Anyway it's booked in with you on Friday for servicing and sorting the overheating out.
     
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