Type 4 flap and oil cooler questions

Discussion in 'Engine & Transmission' started by paul77, Feb 1, 2017.

  1. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    Since the installation of the AC to my bus and the first summer I have started to (been forced to really) investigate why I have been experiencing high oil temps. I recently removed the rear fan shroud to investigate the cooling flaps situation.

    The critical flap that directs some of the fan air through the oil cooler was missing, so I made one up based on one that CVD had for me to template off.
    flaps.png

    I put it a back together and observed no difference in the oil temps.

    I checked the pressure relief valve, the spring was intact, plunger was moving smoothly and the galley seemed to be clear.

    So now I suspect that the oil cooler itself may be blocked? I am seeking guidance as to:
    a. whether this can be checked without disassembly (I am prepared to remove entire shroud but this job has become larger since AC compressor was mounted to the shroud)
    b. what after market coolers I should consider, assuming straight replacement is the way to go. I noticed justkampers and classicveedub sell replacement items at $150 and $100 respectively, OE type are probably twice that.
    c. should i just consider replacing this cooler with a plate to run a larger external oil cooler, as below. I am only considering this as I expect a fair bit of this engine, running AC, towing 400kg and 14ft SUP board on roof.
    http://www.mamotorworks.com/VW/product/oil-cooler-block-off-plate-for-type-4-engine-only-325130-4
     
    Last edited: Feb 1, 2017
  2. cbus

    cbus Well-Known Member

    Messages:
    10,666
    Location:
    sunshine coast
    Chidori's overheating issue was finaly traced to externaly blocked ( air flow) oil cooler.
    Having installed the flap you will likely have seen if this is an issue.?
    It seems that you run higher than normal temps regardless of AC or towing.
    Cant remember what temp senders you have.
    My thoughts would be monitor both head and oil temps.
    No use dropping oil temp if heads are still running hot.

    Also I consider it worth a new stock oil cooler but cant guarantee its the only issue.
    Cant day what aftermarket quality is like but would want that sussed.
    Removing shroud only way to change it.

    I have a spare sandwich plate if you want to play with external cooler.
    Note which way the oil must flow.
    Doc did a post on that about 6 minths ago.
     
    paul77 likes this.
  3. Andy.

    Andy. Active Member

    Messages:
    401
    Location:
    Brisbane
    How complete is the rest of your cooling system? EG engine bay seal, no gaps in tinware, no heater tubes open etc, rear hatch seal? These can all cause leaks from below into the engine bay. I know you have seen a sudden temp change, but anything dislodged or left out during the install?
    Is all the tinware in place around the cylinders (plates under the barrels, tinware below the heads/pushrod tubes etc)

    The other one I have noticed have a big effect on oils temps is engine RPM, but if your running on the highway I assume nothing has changed there?

    I also assume the plate you made up is fairly close to stock, and you have a way to ensure it stays hard down against the oil cooler? I can't quite see it in the picture, but there is some tinware above the cooler that this flap mates to and ensures air flow does go through the cooler and not bypass it?

    Just a few other points to consider in your checking!

    All that said, it has been much hotter than normal, and the temp of an aircooled engine goes up and down with ambient temps, so this would account for some (all?) of the increase.

    With the relief valve (the oil cooler bypass), the springs do tend to loose tension after a while, so worth looking into. I have done it in the past to put a spacer under the spring as a quick cheap way to see if it makes any change. It can also help push oil through the cooler if it's partially blocked. Not a permanent solution, but a simple test.
     
    paul77 likes this.
  4. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    Thanks col and Andy for your responses.

    In the last pic, you will see a screw in LHS that i added to ensure flap was firmly against cooler. Even without the flap there was a fair bit of 'wind' getting through cooler. All seals and tinware is now in place, the flap was the only bit missing. I had been considering the relief valve, may try the washer thing.

    Engine bay seals are good imho, also have exhaust shield in place. http://forums.kombiclub.com/threads/another-kombi-burns.43526/page-3#post-482337

    Over the last 12 months have for various reasons replaced spark plugs, leads and distributor (dual vacuum unit dodgy) and haven't seen a change in oil temps with any of these. I was really hoping that this flap would make a difference.
     
  5. Andy.

    Andy. Active Member

    Messages:
    401
    Location:
    Brisbane
    Looking for a blockage might be what's needed then. What temps are you seeing in the oil (and where is it measured?)
    In my experience, timing/tuning etc affects head temps more than oil.

    Engine RPM and a good oiling system (good pump/relief/bearing clearances etc) seemed to have the biggest effect on oil temps. I have ceramic coated (stock) exhaust and ceramic coated the heads and piston crowns. This had a big affect on lowering head temps, made no difference to oil temps. I had expected the coating on piston crowns might have affected the oil temp a bit, but it didn't.
     
  6. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    Here are some pics of spark plugs. Col suggested to check. These plugs are 6 months old and after a run from byron.
    plugs1and2.jpg plugs3and4.jpg
     
  7. cbus

    cbus Well-Known Member

    Messages:
    10,666
    Location:
    sunshine coast
    Need sharper photos.
    Looks lean on hwy.
     
  8. Grantus

    Grantus Well-Known Member

    Messages:
    13,997
    Location:
    Southern ACT
    So it's not just me thinking "Should have gone to Specsavers" :confused:
     
    Last edited: Mar 2, 2017
  9. merrymike

    merrymike New Member

    Messages:
    22
    Location:
    Melbourne, Australia
    With those flaps - they are meant to close when the engine is cold so that the engine heats up faster. They don't "direct air" as much as shut it out. The control wire and bellows on mine are disconnected so they are permanently open (They are spring loaded to pop open as default if the control wire and bellows fail) My mechanic explained to me this is common in Australia where we don't have the really cold European winters.

    So making up flaps may have been a waste of time.

    Your plugs look like you are running lean - this will heat you up.

    Have you got the hot weather spark plugs?
     
    Last edited: Mar 2, 2017
  10. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    Getting the carbs sorted shortly to sort out bushes and jetting. That one flap I re-instated does function to force 20% of the fan air through cooler in it fixed fully open state. But my experience has been with this bus in it current state of tune that re-instating it had little effect. Without the flap, cooling air still finds its way through the cooler. And it was a big job getting access to the flap, so certainly does feel like a waste of time.:(
     
    peter drogi likes this.
  11. 1500king

    1500king Well-Known Member

    Messages:
    1,503
    Location:
    Adelaide, SA
    Surprised you had to make up a plate, they are not uncommon to find.

    Your plugs, although pics not completely clear, show enough that they are burning lean, read my last message re: carbs. This alone creates LOTS more heat.

    Not enough advance will create heat.

    Have you installed the insulating plate above the muffler, installed the heater port non-return flaps in the bottom of the fan housing?
     
  12. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    Surprised you had to make up a plate, they are not uncommon to find.
    I would have liked to avoid having to make it up myself but on-one in vw community here seemed to have one to spare
    http://forums.kombiclub.com/threads/type-4-thermostat-flap-lhs.54873/
    https://forums.aussieveedubbers.com/viewtopic.php?tid=111992
    If anyone in SA has some to s[pare please put them aside and I will bring some back to QLD next time I get back.

    Your plugs, although pics not completely clear, show enough that they are burning lean, read my last message re: carbs. This alone creates LOTS more heat.

    Not enough advance will create heat.

    Have you installed the insulating plate above the muffler, YES
    installed the heater port non-return flaps in the bottom of the fan housing? NO Don't understand how this would cause overheating. thought they were just to make the heating more efficient but willing to be convinced otherwise? http://www.ratwell.com/technical/Heating.html
     
  13. 1500king

    1500king Well-Known Member

    Messages:
    1,503
    Location:
    Adelaide, SA
    Paul, The heater boxes are on 'Vent' when the heater isn't on. The 'mushrooms' on top of the heater valves are the vent when your heaters are closed. This vent closes when you turn the heaters on. When you are going down the road, air enters the vent and pushes hot air from the heater box toward the fan housing, and into it if the one-way flaps are not there. You will also find one-way flaps in the heater fan housing so that hot air does not come up the paper heater pipes in the engine bay and through the heater fan. So when your heater is off, air can only be expelled through the heater valve vents when the heater is off, not enter the engine cooling circuit. Everything in blue within the link to the pic you provided needs to be in place and functional if you have it there.
     
  14. paul77

    paul77 Well-Known Member

    Messages:
    918
    Location:
    Brisbane
    The only flaps that were in place are the plastic ones in heater fan. Now to try and locate these lower flaps.
     
  15. 1500king

    1500king Well-Known Member

    Messages:
    1,503
    Location:
    Adelaide, SA
  16. 1500king

    1500king Well-Known Member

    Messages:
    1,503
    Location:
    Adelaide, SA
    Also forgot to mention that the flap you have made needs to stop at the pins on the fan housing, otherwise air will be insufficient to the left 2 cylinders.
     
  17. combyuro

    combyuro New Member

    Messages:
    6
    Location:
    Brisbane
    My 2 litre engine has been running too hot since I rebuilt it. And a few weeks ago it overheated taking a trailerload to the dump. Had to wait an hour for it to cool, and get RACQ to jump start it.

    I bought a "SaveMyBug.com" hot oil sensor from the USA, it doubles up onto the oil pressure warning light. Arrived last week, and today the warning light started blinking after a 20 minute trip. I checked the temp at the oil sump fins with a meat thermometer - 195F that's 90C, and WAY too hot for my liking. The thermostat that operates the flaps is fully shrunk at just 70C.

    Here's what I did, that seems to have helped:
    1) made it run richer by turning out each mixture screw 1/4 turn.
    2) checked the timing, and put it at about 8-1/2 before (1 degree advanced from spec which is OK if running premium fuel). Then I reset the idle speed.
    3) MOST IMPORTANT: I finally sealed up the two holes coming up from the heat exchangers that are supposed to connect to the heater fan. I don't have a heater fan (yet...). One hole is round and the other hole is oval. I suspect that if these holes are not sealed, the cooling fan just pumps air out into the heat exchangers and back into the upper half of the engine bay.

    Then, I went for another 20 minute trip. Admittedly, the air temperature was a few degrees cooler, but the engine temperature was markedly different. Firstly, the oil temperature warning light did not come on at all. When I got home, I checked the temperature again at the oil sump fins. 165F - that's 74C.
     
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  18. Weekender

    Weekender Well-Known Member

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    458
    Location:
    Ashgrove
  19. cbus

    cbus Well-Known Member

    Messages:
    10,666
    Location:
    sunshine coast
    I wouldnt expect a probe thermometer to measure anywhere on sump external surface accurately.
    An infra red on sump plates or oil filter should be a better option.

    90C is a good temp.

    Blocking heater box vents is definately necessary.
     
  20. 1500king

    1500king Well-Known Member

    Messages:
    1,503
    Location:
    Adelaide, SA

    Your idle mixture screws only adjust the idle mixture when the throttle valves are shut(idle). As soon as you crack the throttle, the idle mixture is controlled entirely by the FIXED idle jets in the cut-off solenoids throughout 3 idle circuit progression ports. Once air speed increases, you move onto the main jet circuit, the idle circuit on each carb then becomes redundant(they get fuel from BEHIND the main jets). The central idle circuit fuel jet(0.45mm) supplies the top up mixture at idle and also a little under high speed and load where the mains are sized for it to be in place.

    Timing is a little forgiving, for initial advance but mechanical starts at 1000rpm and vacuum should not be operating when you set. This is assuming you have the correct bus distributor and it is functioning correctly.

    The non-return flaps at the bottom of the housing still need to be in place, yes, block the risers off if you don't have heater hoses.

    The 2L thermostat opens at an under-barrel temp of 90-95C. This is normal, AND the skid plate between the heater box and case needs to be fitted to avoid cooler air from under the car influencing opening temp.

    Nothing wrong with oil temp of 90-100C. Oil that is too cold(and for too long) will accelerate wear.
     

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