Type 4 running cold.

Discussion in 'Mech Tech' started by Bushoarder, Jan 16, 2018.

  1. Anyone got any thoughts... engine is an upright converted type 4 in an prototype bay (no thermostat yet) and I’ve run the stock type 4 cooler.

    Engine never gets over 70c which isn’t good for it - other than the thermostat what else could cause this?


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  2. Obvious question - is your oil temp gauge working ok? Done the boiling water test?
     
    Dicky likes this.
  3. This. I would have thought thatsway too cool to be right
     
    Clive Neilands and snotty like this.
  4. Faust

    Faust Supporter

    Has the thermostat cable snapped ? ...also if you have a stat which does not open at the right temp , it will take a good while for the engine to warm up ...especially this time of the year .
     
  5. Faust

    Faust Supporter

    On the up side , at least you don't have to keep pulling into a layby for it to cool down ;)
     
  6. 77 Westy

    77 Westy Supporter

    VW used an unusual system where an attempt was made to control temperature and pressure with one valve. If you deviate significantly from the recommended oil spec (viscosity) or the pressure control valve has been modified or a large oil pump has been fitted then the valve will be unable to control the temperature.

    But fit a thermostat before looking at anything else. What are the cylinder heads temp?
     
    3901mick likes this.
  7. Betty the Bay

    Betty the Bay Supporter

    My type 4 engine is set up correctly and running well.....it doesn't have a thermostat fitted....but it certainly doesn't run cold !
    I think the missing thermostat is a red herring.
     
    Clive Neilands likes this.
  8. The missing thermostat will just mean it takes longer to reach working temp ( promoting premature wear ) if its possible to fit on a upright conversion .
    you don`t say what fan you are running but I would say if a smaller type 1 then you would think it would run hotter or if its a porker fan I`d say cooler
     
  9. 77 Westy

    77 Westy Supporter

    It might be worth reading this http://www.ratwell.com/technical/Thermostats.html The thermostat doesn't open until 85-90C and there is a relationship between the thermostat and the oil and head temperatures.

    Incidentally why did you fit upright cooling to a bus?
     
  10. davidoft

    davidoft Sponsor

  11. 77 Westy

    77 Westy Supporter

    Just seen the pic on VZi. Why don’t you fit a thermostat in the oil lines to the cooler?
     
  12. MorkC68

    MorkC68 Administrator

    Major used to have one fitted when he came from the States, the oil cooler was in the l/h battery tray with the stat set to switch the fan on around 95 deg C (from memory). It did work quite well and the quality of the oil after 3000 miles was surprisingly good, quite a nice colour and not black/smelly.

    All in all it worked well.

    * We haven't got the correct thermostat or flaps in place (but have them to re introduce when the motor gets rebuilt)
     
  13. 77 Westy

    77 Westy Supporter

    That would have been an addition cooler Mark? Bus Hoarder has a type 4 cooler where a type 1 would have it - I think – connected with a couple of hoses from an adapter on the crankcase. Upright cooling.jpg
     
  14. MorkC68

    MorkC68 Administrator

    Yep it has a two port plate under the oil filter housing, somewhere..in time I'll grab a photos. For hoses, read PVC pipe to start with (I may have a photo) but we replaced with better, more suitable hose!
     
    77 Westy likes this.
  15. mikedjames

    mikedjames Supporter

    It may be running cool because you have tuned it rich and are driving gently.
    It takes 15 to 20 miles for my T1 engine to go from cold to really hot, driven at 65mph plus.

    Possible problem is when you get it right , the upright cooling is only about 80% of the airflow (T1=650 CFM vs T4 =800CFM) of stock T4 cooling. So you will start to risk damaging the heads at lower power output, than a T4 cooled engine.

    You also really need airflow through the heat exchangers as these are actually cooling the heads near the exhaust ports on a T4.
     
  16. Interesting comments all. It’s an upright because fitting stock type 4 in an prototype bay is a challenge without chopping the engine bay about.

    I must admit I’ve seen a lot of people running the conversion in splits etc and it’s no worries on overheating but the air flow point above is a concern. I have 90% of the stock t4 cooling tin (sold off the fan and housing) and I have considered going back to stock type 4 cooling for a number of reasons. This took a lot of effort to get it into the bus but it seems to run well.

    I think I have the mains too rich so that’s possibly the issue along with no thermostat and short runs. On a 30 min cruise at 70mph it still kept at 80 max.


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  17. [​IMG]
    As it is now.


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  18. 77 Westy

    77 Westy Supporter

    The oil might be cold but those heat exchangers will be roasting with no airflow through them.
     
  19. That’s a good point. Overheating of that area could drop valve seats I guess. Easy enough to connect the fan housing up - even to an electric fan would help.


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  20. 77 Westy

    77 Westy Supporter

    Or replace the heat exchangers with J tubes.
     

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