AAZ cold start + overheating

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chalkywoods
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AAZ cold start + overheating

Post by chalkywoods »

I bought my T25 in July and have been doing a fair amount of work on him since then. He started as an Aircooled in 1981 but has had an AAZ put in around 8 years ago. Once the engine is warm it runs pretty nicely but there’s a couple of issues I want to sort out.

Cold starting

As it has got colder I’ve found it harder to start the engine and the clouds of smoke coming out the back have got bigger and bigger, around 2 minutes at this point. I’m not really sure how my glow plug system works. There’s a relay at the back (90 464 952) and a new button and light at the front, when I hold down the button (previous owner said 7-8 seconds) the light is on, and off otherwise. There’s no other feedback apart from that, and that’s all the instructions I got, what can I do to check it’s all working well? The glow plugs themselves are the ones that came with the bus, so I’ll probably replace them anyway.

As far as I can tell there’s no cold start advance hooked up. There’s a cable grommet on the inside of my injection pump (1 465 530 828) so I’m guessing there’s a lever somewhere down there, does anyone know what it looks like?

Image

Overheating

When the engine is running it sits at 3/4 on the temp meter and on any long hills it creeps up and I’ll eventually get flashing temp light. Twice I’ve badly overheated. The fan has never turned on but I’ve had a garage take a look and he said it’s because not much coolant is getting through to the radiator. Ill be draining the system soon to add a heater so I want to know if there’s anything I should be doing before/during that.

Here is a picture with most of the hoses marked:

Image


Red and green radiator hoses are always hot when the van stops so I’m pretty sure my thermostat works to some extent, ill check that when the system is drained.

In pictures I’ve seen the thin purple hose goes to the expansion tank but here I’ve got the much wider pink one doing that job instead, is that right?
Any ideas what the blocked off section of yellow bypass hose is for?

Lastly, the blue heater hose goes straight from the front of the block back to the radiator return as there was no heater put in when the engine swap was done. I’m guessing that when the thermostat is open its much easier for the pump to just pull hot water through this that drag it all the way through the radiator. I’m fitting a heater up in the front soon using this feed so hopefully that will sort out some of my problems.

Does anyone know what’s up or is able to provide a picture of a properly circulating AAZ?

Thanks in advance!
1981 Moonraker 1.9TD AAZ
Sheffield/Herts

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ELVIS
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Re: AAZ cold start + overheating

Post by ELVIS »

Cold start - usual drills. Check you’re seeing 12v at plugs and work back from there if not.
If you are check plugs. Also check pump and cam timing are Bob on.

As for temp, hoses are wrong way round for a start. The red/green are wrong- the one coming from side of head goes to the coolant pipe nearest the OS.
Looks like it has a combo of golf hoses fitted badly.
Should be a hose coming out of the back of the head for heater.

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syncroandy
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Re: AAZ cold start + overheating

Post by syncroandy »

Well spotted that man. Radiator feed and return are swapped over !

Re. heater connections not apparent in the pic.. maybe the converter never got around to installing a heater !?

Brrr !
Syncrosport
Volkswagen Transporter, reloaded.

252 GC5 EJ25 AAN L90D
246 097 AFN AVL+ L90D

chalkywoods
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Joined: 27 Jul 2020, 16:48
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Re: AAZ cold start + overheating

Post by chalkywoods »

Cheers guys, I'll check the plug voltage when I get a chance.
ELVIS wrote: 29 Oct 2020, 23:56 As for temp, hoses are wrong way round for a start. The red/green are wrong- the one coming from side of head goes to the coolant pipe nearest the OS.
Good spot, and that OS coolant pipe goes to the top of the radiator, is that right?
syncroandy wrote: 01 Nov 2020, 09:11 Re. heater connections not apparent in the pic.. maybe the converter never got around to installing a heater !?
Correct unfortunately, I've got a heater going in once the rear wheels are back on. The heater hose is there just hidden behind the others, it feeds straight back from the head round to the radiator return hose (green).
syncroandy wrote: 01 Nov 2020, 09:11 Brrr !
Defog is currently provided by the open windows :shock:
1981 Moonraker 1.9TD AAZ
Sheffield/Herts

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