half an hour holiday (overheating)

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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

Gave the radiator fan a quick test with the paperclip jumper on the plug behind the bottom grill and that is working on high and low when directly triggered, small steps but enjoying learning these things...

Still not entirely clear on the flushing process, anyone got any advice for a 1.7 diesel? I'm guessing I can use the disconnected pipe where I've taken out the thermostat as one point - should that be an in or out? I did have a look on the Wiki but where it says disconnect large pipes at lowest point, is it talking at the radiator end? Just being cautious as want to make sure I understand it fully.

Cheers!

 
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colinthefox
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Re: half an hour holiday (overheating)

Post by colinthefox »

Well done for finding the problem, but my recommendation is to keep investigating.

Thermostat only has to be open just a tiny crack for the engine to cool and the radiator to get hot under normal running.With heavier load and/or hot weather it can tip the balance.

With the system empty, now is the ideal time to inspect and flush out the rad. To flush the rad, take both the hoses off the radiator stubs, and use a hosepipe to squirt as much water through the rad as you can, stuff a rag around the hosepipe to make some kind of seal. You'll probably get wet! Keep going till the water comes out clean. You can also do this from the pipes in the engine compartment as long as they go to and from the radiator. Flush in both directions.

When it's all full again, test the rad fan by getting the engine hot with a 20 minute drive with the heater off. Then leave it stationary and idling. After a few minutes the fan should come on for about half a minute then switch off, then do it again a few minutes later. [E D I T] the paper clip test is good, but tests the fan and not the switch itself[/E D I T]

You should also test the low level coolant level alarm in the header tank. Disconnect the plug, then run the engine. The red light should flash and the temp gauge rise to maximum. (I'm Not sure that on ALL systems the temp gauge will rise to maximum. Others will know better.) This alarm might just save your engine in the event of a coolant leak. (It saved mine :D )

If the scum is minimal and light brown, you can ignore the possibilty of oil cooler/warmer failure. It's probably the Radweld stuff.

Then you can drive with confidence.
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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

Thanks so much for the swift reply and the info. Really helps so much having people hand holding me through this tbh!

Flushing method clearer now, flush in both directions a very useful bit of info..

What you say about the fan makes sense, I know it isn't shot from the paperclip test, but yes, need to make sure it is getting triggered under correct driving conditions. Good info about the coolant alarm too, will add that to the list!

Thermostat should be arriving tomorrow, meanwhile got to figure out how to find a very long hose as van is currently sitting about 5 doors down from our house (on street parking only!).

In the meantime will go and investigate the pipes a little further

tbc!
LHD 1989 Diesel 1.7 somewhat homebrewed

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Mr Bean
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Re: half an hour holiday (overheating)

Post by Mr Bean »

Some Bean style "time wasting :wink: " Lilly gilding:
For the coolant to transfer heat into the expansion medium - wax capsule there must always be an (albeit small) coolant flow though the thermostat when in the closed position. Depending on manufacture this can be provided by a small gap in the valve, a bleed notch in the valve or a jiggle pin ball or mushroom ended valve pin which closes when coolant flow increases. Were this not provided the resultant zero coolant flow would prevent the thermostat from opening at all.
 
This solution has its equivalent in a domestic heating installation where one radiator – usually the bathroom towel rail, is set up to allow a small predetermined flow at all times and is not adjustable by hand. If no circulation were possible the boiler would wastefully cycle on and off under the control of the boiler stat reducing the life of the boiler.
:ok
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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

nice, all good info!

So, I flushed out the cooling system (used pipes at the back as didn't fancy trying to remove the spare wheel and get to the others where I was parked), put pipes back (without the faulty thermostat), filled it up and took it for a spin.

About twenty five minutes and a couple of testing hills and only just about reached the magic halfway mark on the temp gauge shortly before arrival back home. Took a good while to warm up, as is to be expected without the thermostat.

No sign of fans kicking in when idling, have ordered a new switch to test with.

Re: low level coolant level alarm, disconnected the sensor (also just removed it from the header tank and connected it) but no flashing red lights or movement on the temp gauge whatsoever. Current across the sensor pins without engine on was minimal (0.1v) forgot to test with the engine running. Will try and tag one on to my Brickwerks order.

Feels good to be chipping away at the problem! So grateful for all the wisdom from those who have been there already.


 
LHD 1989 Diesel 1.7 somewhat homebrewed

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937carrera
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Re: half an hour holiday (overheating)

Post by 937carrera »

Keep chipping away and get that thermostat fitted.

Diesels run cooler than petrol engines so it will take a long time to warm up.

Did you get much crud out, or was it a fairly clear system ?
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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

thanks, tbh not as filthy as expected. Was a murkyish brown but flushed clear and didn't look oily - not really any flakey or floaty bits. I think I'll get a much clearer picture tomorrow once I look at the clean water that has circulated

Hopefully should have the thermostat and coolant delivered tomorrow, will wait until everything else is fully tested before adding the coolant..

Will check water levels and take her for a bit of a longer drive to test temp and fan again.
LHD 1989 Diesel 1.7 somewhat homebrewed

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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

So I think I must have done something serious to offend the VW gods....

Thermostat in, just getting it up to temperature, went to the front to have a look at the bleedscrew to discover it gone ... and this on the floor

f************ !!!

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it has sheared and the rest is still inside the radiator. Feels like now I may be truly screwed (to coin a phrase)...

Anyone any thoughts on how to tackle this new and slightly daunting challenge?
LHD 1989 Diesel 1.7 somewhat homebrewed

pkrboo
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Re: half an hour holiday (overheating)

Post by pkrboo »

redsnapper wrote:So I think I must have done something serious to offend the VW gods....

Thermostat in, just getting it up to temperature, went to the front to have a look at the bleedscrew to discover it gone ... and this on the floor

f************ !!!

Image

it has sheared and the rest is still inside the radiator. Feels like now I may be truly screwed (to coin a phrase)...

Anyone any thoughts on how to tackle this new and slightly daunting challenge?
I have a rad for sale. £20 plus post

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1.6 CS Diesel DOKA

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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

cheers pkrboo for coming to my aid, do you know which model van it came out of?

Just having a look if these are universal or not...

If you could pm me a couple of pics of the radiator that would be great, this is all new territory ;)

Mine is a 1.7 diesel..




 
LHD 1989 Diesel 1.7 somewhat homebrewed

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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

well would you freakin believe it...

Managed to use the point of a flathead screwdriver on the sheared bit still inside the radiator and got it turning and out!

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Now to track down a replacement... onwards!
LHD 1989 Diesel 1.7 somewhat homebrewed

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937carrera
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Re: half an hour holiday (overheating)

Post by 937carrera »

Well, that's a fortunate escape

So now you need a bleed screw...... and a smaller spanner to tighten it. :wink:
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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

goodness me man, fortunate indeed!

The crazy thing is I wasn't even tightening it at the time, I just looked, noticed it was gone and found the sheared part on the floor, you can probably imagine the look on my face!

Need to get some calipers on it, but I'm guessing this is the nearest Brickwerks have:
https://www.brickwerks.co.uk/set-screw- ... 8-bzp.html

There is a nut and bolt specialist not a million miles away I might take it to tomorrow to match it...
LHD 1989 Diesel 1.7 somewhat homebrewed

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937carrera
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Re: half an hour holiday (overheating)

Post by 937carrera »

I just looked the part number up

010 237 6

The description says M8 x 12 hex head bolt.

Your bolt specialist should be able to check and confirm the thread pitch, but it's probably just standard. You might need to get a longer bolt and cut it down / file the end ;)

But..... getting one in brass will be more difficult, you might be better going for the s/h rad anyway

E D I T: the one you linked from brickworks is the correct one :)
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
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redsnapper
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Re: half an hour holiday (overheating)

Post by redsnapper »

sweet, thanks. Ordered!
LHD 1989 Diesel 1.7 somewhat homebrewed

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