1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Engine overheating?

Discussion in 'Engine & Transmission' started by TeeBee, Aug 9, 2018.

  1. TeeBee

    TeeBee New Member

    Messages:
    18
    Location:
    Melbourne
    Hi, I recently got a '76 Bay 2ltr microbus. I haven't driven it very much so far, but the other day I took it for a short drive, about 10-15 minutes, over to the shopping centre. It was a reasonably cold day, about 13 deg max here in Melbourne. When I got there, I went to get something out of the back, and there was a lot of heat radiating out from the engine area. It was like a furnace down there. Is this normal? I know they run hot, but for such a short drive on a cold day I was really surprised! I'm only just learning about aircooled engines, so I really don't know how hot is too hot... Thoughts anyone?
     
  2. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,662
    Location:
    Penna, Hobart
    It is possible you may have an issue but the more likely, if you have the foam engine seal fitted and intact as well as all of the engine tin, that you may be just feeling the heat off the muffler. Without pics it is a little hard to tell, and there are many factors that need to be considered.

    Chuck up some pics of the engine taken from the back and also underneath and we might be in a better position to give you some advice.

    Adrian
     
    TeeBee likes this.
  3. rstucke

    rstucke Well-Known Member

    Messages:
    599
    Location:
    Wamberal NSW AUS
    make sure something isn't covering the air intake for the cooling section of the engine or the fan blades in there. Sometimes people leave rags in the engine compartment that result in a quick over heat.
     
    TeeBee likes this.
  4. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    673
    Location:
    Bateau Bay, NSW
    The muffler is right next to your rear bumper and your muffler gets really hot in a short time.
     
    Mordred and TeeBee like this.
  5. 76kampa

    76kampa Active Member

    Messages:
    117
    Location:
    Perth
    If the engine was running then you can feel the warmth, but if it wasnt then it might have just been a breeze blowing in the right direction, under the bus.... dunno, when I stop mine the top of the engine is quite cold, I think that's odd.
     
    TeeBee likes this.
  6. cbus

    cbus Well-Known Member

    Messages:
    10,786
    Location:
    sunshine coast
    As said above. Common for a lot if things to be wrong and cause overheating.
    This can stress or kill an engine.

    I strongly advise purchasing an infra red type temp guage to check on sump plates and oil filter.
    https://m.ebay.com.au/itm/Digital-N...m=272713372248&_trksid=p2385738.c100694.m4598
    A 500C version would be better.

    This will start to put some quantative numbers on the issue.
    Look for temps between 90-100 as being ' normal'.

    Photos do help .

    A check that all tinware and foam seal in place is a starter.
    As is a check of timing.

    Pull a couple of spark plugs to check colour of electrodes.
     
    TeeBee likes this.
  7. TeeBee

    TeeBee New Member

    Messages:
    18
    Location:
    Melbourne
    Thank you all for your words of wisdom. I was looking in the engine bay this morning and taking some photos when I noticed the glaringly obvious... :confused: I don't know the correct terms for these things, so I'll just show you in the photo below. My mechanic put in a new battery last week and must have bumped things around a bit. Nevertheless, I think I will be investing in one of those infra red temp gauges, in case the problem isn't quite so obvious in future! (Or I don't notice the obvious...).

    kombi engine.jpg
     
    Mordred likes this.
  8. Barry

    Barry Well-Known Member

    Messages:
    2,535
    Location:
    Abbotsford NSW
    TB

    That is your heater pipe

    The fan blows air over the exhaust heat exchanger to warm the cabin
    Loosen off the screws and reconnect the black hose
     
    TeeBee likes this.
  9. TeeBee

    TeeBee New Member

    Messages:
    18
    Location:
    Melbourne
    :D ok, so I haven't found my engine heat problem then... I will buy one of those infra red temp gauges and then work out if I really have a problem or not. It might just be normal engine heat that I'm panicking about. I was just surprised that it was so hot after a short drive on a freezing cold day. I'm pretty sure it wasn't just the muffler, it seemed to be the engine. Here's another pic of the engine in case there's anything relevant for the clever people to spot.

    kombi engine.jpg
     
  10. AC-T3

    AC-T3 Well-Known Member

    Messages:
    829
    Location:
    Woy Woy
    As suggested check temps on the bottom of the engine, and pull the plugs to check colour. Also be aware that these engines run really high head temperatures, I mean real hot with up to 350F being normal, anything over 400F cause for concern. All air cooled motors should be fitted with means to monitor CHT.
     
    TeeBee likes this.
  11. rstucke

    rstucke Well-Known Member

    Messages:
    599
    Location:
    Wamberal NSW AUS
    That was probably the source of a lot of hot air in your engine bay.
    When those hoses are displaced the engine fan that passes air over the exhaust heat exchangers and then outside the engine bay (through the heater pods, when the heaters aren't used) puts that very hot air into the engine bay for the engine to recycle it and get even hotter.
    Replace the hoses on there spigots and se how you go.
    An infra red thermometer is the way to go.
     
    TeeBee likes this.
  12. TeeBee

    TeeBee New Member

    Messages:
    18
    Location:
    Melbourne
    Thanks rstucke, I was feeling like a bit of a dumb-dumb for thinking that hose was part of the problem! But if it was part of the problem, then I feel a bit better. :)

    I will definitely look into this! Thanks, AC-T3.

    Tee Bee
     
  13. 76kampa

    76kampa Active Member

    Messages:
    117
    Location:
    Perth
    How can that be, I dont even have the hose on mine at all....
     
  14. cbus

    cbus Well-Known Member

    Messages:
    10,786
    Location:
    sunshine coast
    Then I hope it is blocked off.
    Air is constantly blown thru the heater boxes from the lower ducts in the fan shroud.
    The electric fan is only a booster.
    There are flaps in the electric fan housing to prevent sir coming up via the tubes when fan is not operating.
    The fan forces engine bay air into the heater boxes when operating.

    If the tubes are not connected then very hot air from heater boxes enters engine bay.
    It is critical to keep the hot area
    ( underneath of engine ) separated from the cooling and intake air within engine bay.
    Hence the importance of maintaining all tinware and engine to body foam seal.
    Same applies to seals around the heater box tones/ tinware plus upper fan flaps and same in lower cooling fan shroud that feed to the heater boxes.
    Check grommets on spark plugs and oil pressure sender.
     
    TeeBee likes this.
  15. cbus

    cbus Well-Known Member

    Messages:
    10,786
    Location:
    sunshine coast
    Another item often missing is heat shield between muffler and engine tinware.
     
    TeeBee likes this.
  16. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    673
    Location:
    Bateau Bay, NSW
    Vacuum air leaks can cause hotter running temps. So here’s some quick help on that. There are some comprehensive checks described elsewhere particularly on Itinerant Air Cooled web site written by “Amskeptic”.

    Check all the hoses on the central idling circuit. If they’re not like new, replace them all. To access them, you remove the air filter box. They’re the hoses joining all the pipes that run between the left and right carbs/manifolds across the top of the crankcase. To remove the air box, there are several clips to undo, but it’s all designed for quick removal so it’s not too hard.

    Whilst you’ve got that out, there’s also a metal balance tube / brake booster vacuum supply line running from the left and right manifolds across the front vertical tinware. There’s a rubber elbow on each end. My advice, just replace them with new elbows.

    There’s a vacuum pipe for the brake booster that runs all the way from the engine bay (connects to the aforementioned balance pipe) to the front of the bus that needs checking too. Easiest way to check is to plug the connections at the inlet manifold and see if the idle changes, but beware of driving when you do that as you’ve lost the vacuum assist on your brakes.
     
    TeeBee likes this.
  17. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    673
    Location:
    Bateau Bay, NSW
    Also, get your valve clearances checked/adjusted.

    Set your points gap to 0.45 mm. I found that to be closer to the correct dwell than the 0.4 mm shown in the book. Anyway, it won’t matter too much as long as it’s near spec and not way too big/small.

    Then, get the ignition timing set to 28-29 degrees before top dead centre at 3,500 rpm with vacuum advance hose disconnected and plugged.
     
    TeeBee likes this.
  18. TeeBee

    TeeBee New Member

    Messages:
    18
    Location:
    Melbourne
    Does anyone have a photo of what this should look like? So that I can see if I have said heat shield?

    Thanks for all that information Mr Beckstar, but it all seems a bit over my head at the moment! I only just found out yesterday what part was the heater hose! I will keep learning though and hopefully one day I'll be able to follow your instructions. :) I have bought a Bentley manual, so I'll have to have get reading.
     
  19. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    673
    Location:
    Bateau Bay, NSW
    Here’s a heat shield. It’s located above your muffler and below the rear tinware.
    66F0F026-A01E-483F-8716-ADC4843A5666.jpeg
     
    TeeBee likes this.
  20. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,662
    Location:
    Penna, Hobart
    Its ok, All the info you have been given is good, but start with the basics, like fixing that heater hose. Next check all the hoses as Mr Beckstar suggested, which is another easy job.

    After that do some testing to see what temps you are getting. There are other things that can cause overheating but you may be chasing a ghost until you have some figure to prove it. The ideas above are just basic maintenance items/

    Fitting the heat shield if it is missing is a bit of fiddling, and can be a contributor to heat, but the original ones are full of asbestos and mostly rusted, so you will need to find a new one which aren't cheap. A lot of buses don't have one and it isn't a deal breaker if you don't.

    cheers

    Adrian
     

Share This Page