Header tank pipes - '89 SE

[Hammer59]

Was replacing my air filter and knocked off one of the hoses coming from the main cooling system header tank (not chargecooler tank).  It broke off right by the connection to the tank and was probably lucky it did as the hose was very brittle and could have let go any time.  It led me to check both reservoir levels plus expansion tank.  These were all very low and I'll need to keep an eye on those levels.

The hose that broke was the one that returns coolant to the main system (not the overflow hose to the expansion chamber) and I've never seen anything like this.  There is no explanation of this hose's purpose in the manual and wondered if anyone had any information about it.  It seemed odd that a closed system would be connected to just below the neck of the filler tank unless there's some sort of valve where the hose connects back into the system.  Can anyone shed any light?  TIA.Lotus_cooling.bmp

Edited August 19, 2021 by Hammer59

[Barrykearley]

Ahh yes - I’ve broken one of these. It’s an aluminium pipe and it’s easy to break.

Just get a fabrication guy to knock you a copy up in stainless.

[CHANGES]

 

23 hours ago, Hammer59 said:

It broke off right by the connection to the tank

I think you will find Barry is referring to the alloy front pipe connection .. the Tank on the SE is steel ( if still original )  But the connection can be brazed welded or soldered back or a ne alloy replacement obtained .. 

 

23 hours ago, Hammer59 said:

There is no explanation of this hose's purpose in the manual and wondered if anyone had any information about it. 

The hose is there to remove any air from the system during use .. The top of the alloy pipe being the highest point in the cooling system , the bleed point . The air will go to the header tank which should always be full . By means of expansion and contraction of the fluid in the system the air will go to the expansion tank in the boot space over time .  this tank should always have coolant in it which will increase and decrease with temp .. what it does is keep the header tank full at all times . se level marks on tank . This is different to the later models .. Note the CC tank is only ever to be half full.. 

Hope that helps .   

[Hammer59]

Thanks for the input, Barry and Dave.  Sorry, my description was probably a bit vague.  It was only the flexible hose that broke which should be easy to replace although the hose clip at the alloy pipe end is well and truly seized.  The careful application of a dremel should take care of this.  We're actually in a full lockdown here in NZ (first in over a year) so have to wait to get a replacement hose and jubilee clip.  I did manage to pick up some Castrol Radicool Concentrate.  As mentioned, all three reservoirs are very low.  I'm assuming it will be compatible with the existing coolant (green - as is the concentrate).  There's no visible coolant leak anywhere and no evidence of head gasket problems so I'm not sure why the levels are low.

[Hammer59]

Actually - on the cooling system.  I'd like to replace coolant at some stage but I'm a bit worried as my heater has never worked and the heater core wouldn't be opened up.  Would you foresee any issues with this scenario?  A/c doesn't work either - there's no activity at all from the compressor when it's switched on.  Both these are on the 'to-do' list but it may be best to address these before changing the coolant.  Any observations welcomed.

[ramjet]

If your heater valve has not been opened, I would not expect an issue if you opened it now. The valve is generally only there to stop inflow to the core. It should be at coolant pressure when the car is running, Just no flow through the core so no heating.

I seem to recall a Holden that we owned had both the inlet and outlet hoses both went through the one valve. Generally not the case though.

If your a/c compressor does not run, it may be that the system pressure is low and the switch, generally on the drier, is preventing the compressor switching on. If you want to check whether the compressor turns, you could try and turn the front clutch plate of the compressor to see if you can turn the compressor. Depending on the amount of time that the compressor has not been run, the seals may be shot. Using a vacuum pump, you can check the system integrity. If you don't have one, find a reputable a/c service place and take it to them.

[Hammer59]

Cheers Michael.  Not too fussed about the A/C (this is NZ, after all).  I did try to investigate the heater issue a while back but couldn't get the temperature control knob off for love nor money.  Manual's description and diagrams of heating system make them look pretty complex and my body's still recovering from the gymnastics of removing the binnacle last year.  I can't see that tinkering with the heater control system is going to be any less of a stern test for the ol' back, but I'll give it a go soon.

[Escape]

There is a small hole in the HVAC knobs, leading to spring loaded tab on the shaft. You need to push that with a small punch or similar and the knob can slide off. I struggled first time around as well, almost destroying the panel. 😉

Once you get the panel off, it all becomes much clearer. The actual vacuum valves are hard to reach though, you'll need to assume the Lotus position.

[Hammer59]

Thanks Filip.  That info is invaluable.  I was ready to apply a pair of pliers which wouldn't have ended well.  I'll start limbering up!