Author Topic: Hot Melbourne day 34C - 1st test of 6.9 in the heat  (Read 3138 times)

13B

  • Vintage
  • ***
  • Posts: 871
  • Location: Bonerland - I like big butts and I cannot lie!
Hot Melbourne day 34C - 1st test of 6.9 in the heat
« on: 21 October 2007, 02:21 AM »
Had a pretty successful day today - 170km round trip which was mainly freeway driving and some traffic driving.

The a/c works a treat.

So does the cruise control.

Temps were a tad high.  At 110km/h with a/c on full on the freeway it was sitting on 96-98C.  At the lights they'd climb to over 100C but drop back down once moving normally.  Temps went up when driving up hills.  At no time did the thing feel like it was overheating and didn't ping or do anything stupid.

One thing I did notice, was that I was sitting idling on front of my garage door, temp on about 105, a/c on full, realised that the a/c fan was not on, and probably didn't run all day.  Can someone point me to a thread which tells me how to test the aux fan?  Surely with the water temp that high and a/c on that fan should be going sick.    i hope thats all there is to it because although I only have a short drive to and from work, some days its over 40C outside and i do get stuck in traffic, which is when I really need the old grrl to keep her cool...

On the down side I went to wind down the drivers-side window and accidently pressed the button up - 'splink' ... window regulator croaked...
Didn't you get these changed recently, Des?  Oh well...

Ian.
450SEL 6.9 #5440 = V MB 690 , 450SE # 43094 = 02010 H , 190E/turbo # 31548 = AOH 68K

Des

  • Vintage
  • ***
  • Posts: 923
  • Location: Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #1 on: 21 October 2007, 03:35 AM »
young Ian, enjoying the headache ownership of a 6.9 I see

Yes temp gauge would hover, in my opinion dangerously around 100 mark, Mercedes should not move from 80, even with the air con on, in my humble opinion. for me here on days over 20c it would do exactly that

yes the front switches in the console and the window regulators were replaced, like 1 year ago.

It was a good car, but frankly I don't miss these annoyances, I can wind my own windows down and up, and my cars don't overheat.


1977 W123 230 
1977 W116 280S *new*
1980 W123 250
VW Beetle "Oval Window"
VW Golf Mk1
Volvo 240GL
Volvo 740GLE

Big_Richard

  • Guest
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #2 on: 21 October 2007, 03:41 AM »
May as well fix the whole cooling system in one foul swoop, Brand new radiator, water pump and thermostat with all new hoses etc. Only genuine Mercedes parts will do.

Should only cost a measly 8 grand. Pocket change, surely!   ::)

(sarcasm detector about to explode)

Des

  • Vintage
  • ***
  • Posts: 923
  • Location: Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #3 on: 21 October 2007, 03:57 AM »
radiator was recored a few years ago
thermostat was replaced sometime last year, along with the radiator hoses from memory.

1977 W123 230 
1977 W116 280S *new*
1980 W123 250
VW Beetle "Oval Window"
VW Golf Mk1
Volvo 240GL
Volvo 740GLE

13B

  • Vintage
  • ***
  • Posts: 871
  • Location: Bonerland - I like big butts and I cannot lie!
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #4 on: 21 October 2007, 04:03 AM »
Eh its bound to be the stupid a/c aux fan letting the side down.  Have to try to find out why its not coming on.

Either that or bypass is with a switch but thats not the most elegant solution, at least I would know its running without having to trust any relay or thermo-switch..
450SEL 6.9 #5440 = V MB 690 , 450SE # 43094 = 02010 H , 190E/turbo # 31548 = AOH 68K

Des

  • Vintage
  • ***
  • Posts: 923
  • Location: Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #5 on: 21 October 2007, 04:09 AM »
Ian do you mean the thermo fan sensor?

1977 W123 230 
1977 W116 280S *new*
1980 W123 250
VW Beetle "Oval Window"
VW Golf Mk1
Volvo 240GL
Volvo 740GLE

WGB

  • W116 Addict
  • ****
  • Posts: 3,280
  • And on the eighth day he made the 116
  • Location: Perth - Western Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #6 on: 21 October 2007, 07:06 AM »
If it has original wiring and the fan works when fed with power it will either be the switch or the relay in the right kick panel.

The system can be too clever and many of them have been wired up so that they come on whenever the compressor is engaged - this also helps the performance of an H134A converted system.

If it's the fan motor - Electric fans are cheap.

Bill

13B

  • Vintage
  • ***
  • Posts: 871
  • Location: Bonerland - I like big butts and I cannot lie!
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #7 on: 21 October 2007, 05:21 PM »
Thanks Styria.  I've learned from my previous 450SE and 6.9 that the 6.9 tends to be a very warm blooded beast and the temps can get high enough to be of a concern but not at any time did the car feel like it was really hating the temp.  Revs never dropped below where they normally sit at idle (500 or so) and oil pressure never dropped below 1 bar.  Even when switching the car off at my destination and then restarting it 3 minutes later, the heat-soak had the engine at an indicated 110C but it pretty quickly came down to around 100 by turning off the a/c and driving sensibly.

Gonna test the aux fan shortly, ... in hind sight all the indications while yesterday was the the cooling system was capable of keeping the engine in the right range, just that the little bit of additional air needed was not available. 

Des, did you ever see the aux fan in action while you owned this car?  Just curious.

 
450SEL 6.9 #5440 = V MB 690 , 450SE # 43094 = 02010 H , 190E/turbo # 31548 = AOH 68K

WGB

  • W116 Addict
  • ****
  • Posts: 3,280
  • And on the eighth day he made the 116
  • Location: Perth - Western Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #8 on: 21 October 2007, 08:00 PM »
My 6.9 doesn't seem to run that hot although the weather has been mild on the days I have had it out.

It stays at about 80 to 85 degrees.

My concern is that it has green coolant in it - of which I have a total aversion - and don't know at what level it will boil.

I would feel happier with the summer temps here to have M-B blue coolant in it - 50:50 -  after a full flush and a good cap before we get into the 40's here and I am driving through the hills.

Bill

Des

  • Vintage
  • ***
  • Posts: 923
  • Location: Australia
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #9 on: 21 October 2007, 11:31 PM »

Des, did you ever see the aux fan in action while you owned this car?  Just curious.

 

can't say I ever noticed or heard it running,
1977 W123 230 
1977 W116 280S *new*
1980 W123 250
VW Beetle "Oval Window"
VW Golf Mk1
Volvo 240GL
Volvo 740GLE

Seb450SEL

  • Newbie
  • Posts: 10
  • Location: Melbourne, Aus
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #10 on: 23 October 2007, 08:31 AM »
Hey Ian,

Had my 450 out the same day, (last Sunday I guess you are speaking about) doing some city runa-rounds.

With a R12 chilled cabin the merc never went over 100 and the aux fan never kicked in, it may be different with the 6.9’s but my fan is operated by a temp switch on the receiver/dryer at the front of the radiator. I know mine works as I have dipped it in hot water and the fan comes on but not sure at what temp it is set. The receiver/dryer does get hot in service but never too hot. You can short it on by connecting to two wires going in to the sensor and it will stay on. I am sure the aux fan was intended only for use with the a/c system.
Sebastian

1979 Blue 450 SEL

"Goina make a tour Benz out of that Datsun,"

450SLC 5.6 supercharged

  • Enthusiast
  • *
  • Posts: 26
  • Location: Sweden
Re: Hot Melbourne day 34C - 1st test of 6.9 in the heat
« Reply #11 on: 28 October 2007, 05:49 AM »
i think its very important if the fan clutch is operating like it should  and even use a 75 degree thermostat . and rmember i did run it with a big supercharger on top of it .
supercharger6.9