AAZ Thermostat issue?

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mrnickmuss
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Re: AAZ Thermostat issue?

Post by mrnickmuss »

Thanks MGP again! I have been reading up on Darleks mine is a black one and dosent 'quack' so will be ordering a Blau or VW one that does.... along with some 6mm silicon hose!
Small steps....

Mick & Tracey
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Re: AAZ Thermostat issue?

Post by Mick & Tracey »

Hi

I wouldn't panic too much. I had very similar problems with my AAZ doka a few years that had me totally stumped. I ended up with running with a drilled out thermostat until the very helpful and sensible Mr Baxter at Brickwerks actually tested my "overheating" engine with a temperature probe. Result it hadn't been overheating - it was the temp sensor playing up. Disconnected it, cleaned up contacts and Robert was my mum's brother.

I'm not sure that there's too much wrong. Running hotter under load is to be expected and a lot of people say AAZ's generally run a bit hotter. I've also noticed that my radiator can often be stone cold (which used to worry me) - it doesn't necessarily mean there is a problem. Just that engine is not needing to vent excess heat to the rad.

Replacing dalek for a good blue one sounds sensible. Leaks were obviously just teething leaks.

How hot is it actually getting? 3/4 way i wouldn't think is an issue provided it comes down again. Does fan kick in? If it does and temp comes down, then things don't sound so bad.

btw - I never found i needed an extra cooler on mine. It has run with pretty heavy loads (I'd say a tonne or so on the back, plenty of spring deflection!) over long distances without a problem other that temp rises on hills and a relatively sedate speed.

Enjoy your doka. Your work with it sounds great.

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marlinowner
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Re: AAZ Thermostat issue?

Post by marlinowner »

It is worth thinking about the temp sender, on my South African van the temp gauge sits with needle in the middle, but if I fit the gauges out of my old DG van then the needle sits at about 3/4 of the way to max. I presume the sender resistance is different to a DG one.
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mrnickmuss
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Re: AAZ Thermostat issue?

Post by mrnickmuss »

So.....
New darlek cap arrived today. Thoroughly tested thermostat.... Three times just to make sure all working fine.
Fitted thermostat.
Refilled header tank.
Ran up to temperature adding coolant and water mix as required until could fit any more in. squeezed pipes and watched until bubbles stopped a filled to brim. Check expansion cap had minimum amount of coolant. As it came up to temp took it for a run up the road for a tem minute drive. came back and radiator was warm apart from top few cms. Bled the radiator.
Then things got a bit odd....
I couldnt take the darlek cap off without it over flowing.
By this time it was geeting dark so I could shine a light under the header tank I could see there was air in the top of the tank. So I released the darlek just enough to let the air out. I then revved the engine and I could see more air coming into the tank so I repeated for probably ten minutes,
I also checked the raditor which by this time the fan was kicking in and out. The temp gauge in cab was just above half. So all fine there.
So I returned to the engine bay and continued the process of releasing air..... It just kept coming.... as I revved the engine I could see regular amounts of air passing into the tank. Not huge amounts but enough to be noticeable.
so I revved it harder and this continued.
I gave up in the end as I didnt seem to make any progress.
Exhaust smoke was black and the oil is too. So dont think it is the head gasket.
I am wondering if I have a leak somewhere and it is pulling in air?
Any thoughts?

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mrhutch
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Re: AAZ Thermostat issue?

Post by mrhutch »

mrnickmuss wrote: I couldnt take the darlek cap off without it over flowing.
engine running or not at this point?

mrnickmuss wrote: Exhaust smoke was black and the oil is too. So dont think it is the head gasket..
Explain!!
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mrnickmuss
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Re: AAZ Thermostat issue?

Post by mrnickmuss »

Ok Mr Hutch thanks for yor input... I answer to your questions:
Yes the engine was running.
Explain.... After my last engine died when the head gasket went I reasoned from my basic understanding if I had issues with head gasket potentially water would be going places it shouldnt in the engine and creating steam so emissions would be white and or the oil would be contaminated.

mrnickmuss
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Re: AAZ Thermostat issue?

Post by mrnickmuss »

Update.....
Fitted new Darlek cap and bled system. Ran fine without any issues kept temp gauge just on or just above LED. I picked up a load of fire wood on Sunday and ran it up a couple of reasonably steep hill. so happy with that. So much so I drove it home from work and thought I would pop in and see my mechanic friend and smugly tell him I had fixed it. I left it running whilst chatting and guess what? I blew a hose!
I am hoping it is just a dodgy jubilee clip?... I have replaced it and ran it whilst stationary for about half an hour with fan kicking in and out. I have driven to work since with no problems.... So we will have to wait and see!
Thanks to everyone for their help...
Its good to know your out there!!!

mrnickmuss
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Re: AAZ Thermostat issue?

Post by mrnickmuss »

Arghhh!
I was asked the fatal question; 'Hows your van running?'
'Fine' I say.... 'No problems for a few weeks' I say.
Then I get stuck in a six mile traffic jam.
It gets a bit hot first time in ages.
So I bleed the system to make sure, and yes there is air in it.
I semi confidently drive to work watching the temp like a hawk. All fine.
I then pick up a mini bus full of deaf special needs children, who follow me to our woods to do a day of Forest School and yes you guessed it.... I break down, overheating and coolent over pressurising and pouring out of the top header/expansion tank when I take the lid off....
Looks like the head gasket has gone on engine number 2!!!!!!
Time to get the spanners out again!!!!

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