Sorry, bit of a ramble here, but please bear with me.

Been having an issue with my engine in which the cooling fans fail to turn on. They are controlled directly from the oem ECU.
I now have a full copy of the original Rover 620ti service manual (big thanks to t16turbotone for that!) and have been able to trace all the wiring - and it's all fine.
However, further reading of the manual shows that the fans are not meant to come on until the 106degC ! And then, only in a low speed setting. They then only go to full speed at 114degC! No wonder I don't see the fan come on.
Seems a very high temp to me? My problem is that I can't run the car that high before the header tank is full.
Running the fan manually keeps the temp in check, so I've ordered a seperate adjustable fan switch so I can turn the fans on at 85-90.
Problem should be solved, but why am I getting so much expansion in my system? I'm reluctant to say it's 'boiling over' as it's not that hot! The header tank is the original one from the donor so should be big enough.
I'd be interested to know what people think? Is it down to the smaller radiator, the lack of heater circuit, or the use of a davis craig water pump (extra snipit is that the thermostat has been removed as per the water pump instructions)? I've checked for the usual stuff like airlocks etc.

Cheers,
Bill

simply change the fan temp switch and wire it directly through a relay to the fans. My nissans fan comes on at 95 degs, you can buy switches at halfords for a few quid

there even this in line switch and I think car builder solutions also sell them -

linky

yip, bit cheaper too and a range of temps aswell

linky 2

[Edited on 26/2/09 by Mr Whippy]

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Originally posted by Mr Whippy
simply change the fan temp switch and wire it directly through a relay to the fans. My nissans fan comes on at 95 degs, you can buy switches at halfords for a few quid

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bigger bottle then? is it from the same donor?

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Originally posted by Mr Whippy
bigger bottle then? is it from the same donor?

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Originally posted by bilbo
Problem should be solved, but why am I getting so much expansion in my system? I'm reluctant to say it's 'boiling over' as it's not that hot! The header tank is the original one from the donor so should be big enough.
I'd be interested to know what people think? Is it down to the smaller radiator, the lack of heater circuit, or the use of a davis craig water pump (extra snipit is that the thermostat has been removed as per the water pump instructions)? I've checked for the usual stuff like airlocks etc.

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Originally posted by 02GF74

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Originally posted by bilbo
Problem should be solved, but why am I getting so much expansion in my system? I'm reluctant to say it's 'boiling over' as it's not that hot! The header tank is the original one from the donor so should be big enough.
I'd be interested to know what people think? Is it down to the smaller radiator, the lack of heater circuit, or the use of a davis craig water pump (extra snipit is that the thermostat has been removed as per the water pump instructions)? I've checked for the usual stuff like airlocks etc.

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most liquids expand x amount per unit volume per y degrees c. As you have decreased the volume - by removing heater and smaller radiator, you should get less expansion in volume hence your header tank should fill up less not more.

That tells us something is wrong.

Have you filled header tank correctly? Don't they have a maximum mark that you fill up to when cold?

At what temperature does the EWP turn on?

Are you able to watch the liquid in the header tank and take temperature measurements from cold to see how it runs?

If there is an override on the EWP, can turn it on at say 50 degree and see what effect it has?

Is the EWP running, albeit at a lower rate when engine is warming up?

My theory/guess is that you don't have enough water circulation due to EWP not running enough and then getting localised vaporisation in the block causing the coolant to exapand.

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the volume of the cooling system shouldnt be the problem.... it sounds like its pressurising the system from your description, you say the tank fills up after its been running... how long for? have you done a block test.. could be a headgasket leak pressurising the system and "raising" the fluid level in the header tank

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Originally posted by bilbo

I initailly had a lot of issues with the EWP, down to a faulty controller.

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I was hoping no one would mention Head Gaskets but I'm not sure that's the problem - what other signs would I have? I don't think the T series is prone to HGF like the K seires.
The car is not yet on the road. All it's been doing so far is slow and fast idle and the odd rev.
The engine was good when it came out of the donor, and I've not re-built it. Just to confirm as well, the tank only fills up while the car runs - it soon drops down after you shut the car off. It's also a gradual rise in level as the engine heats up until about 90-95 deg when it reaches the cap.
I've tried to draw a diagram here:
Rescued attachment rad.jpg

It sounds like you have either a massive airlock or boiling at local hot spots due to bad circulation within the engine - which could be caused by the electric water pump. It could also be cracked head or liner or head gasket but I think this is less likely.

I think you need to take fresh look at what you are doing

(1) Electric water pump = snake oil

(2) Your engine is designed to have thermostat --- if you take the thermostat out you should fit a resistrictor plate to ensure the water takes the correct path through the block this prevents hot spots causing local boilling .
I would use to a late production Landrover Freelander MK1 1800cc external thermostat and fit a restrictor plate in place of the original. This type of thermostat opens on both temperature and flow pressure.

(3) Your engine needs a by-pass connection (heater connection) to ensure proper flow of coolant through the block.

(4) Your engine is designed to run hot however as you have a smaller raddiator you may need a bigger safety margin so a running the fan off a simple thermo switch which cuts in at 91c or so is a good idea.

[Edited on 26/2/09 by britishtrident]

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Originally posted by bilbo
the tank only fills up while the car runs - it soon drops down after you shut the car off. It's also a gradual rise in level as the engine heats up until about 90-95 deg when it reaches the cap.

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Landrover thermostat --- available in different openning temperatures -- body coluor indicates temperature.

[Edited on 26/2/09 by britishtrident]
Rescued attachment b.png

When I say soon, it's a couple of mins - but this is with the EWP running, (as it does for a while after shutdown) so that could change things.

EWP idea was a necessity rather than a choice as the original pump was intergral with the A/C compressor. I'm also very limited on space.
I'm not sure the fact that the thermostat is missing is an issue as on the donor it never lived in a housing, but literally stuffed in the pipe between the head and the rad.
As for the heater circuit, the feed to it is what I'm now using to feed the turbo, so in effect the circuit is still there. I'd though to actually block this off, but maybe I actually need to keep it, but bypass the turbo?

Thanks for all the help so far BTW. It's giving me lots to think about.


Edited to say, it cools enough in those couple of mins to lower the level off the cap, but takes a lot lot longer to go all the way down.

[Edited on 26/2/09 by bilbo]

[Edited on 26/2/09 by bilbo]

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Originally posted by bilbo
When I say soon, it's a couple of mins - but this is with the EWP running, (as it does for a while after shutdown) so that could change things.

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Sorry, I edited my post to say that it takes a couple of mins for the level to drop just below the cap - it takes far far longer to drop right down. This is without the fan, but it is quicker if I run the fan at the same time.

Also, all the pipes and radiator feel uniformly hot to me, and take a long time to cool down

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Originally posted by bilbo
Sorry, I edited my post to say that it takes a couple of mins for the level to drop just below the cap - it takes far far longer to drop right down.

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Probably best if I post a pic of the setup here:



You can see the shape of the tank. It does curve in at the top, so that may explain some things?

The 'max' level is the lip running round the middle of the tank. Ignore the other empty 'locost' tank - that's for the chargecooler on a seperate cicruit.

I'll do those calculations as you suggest and see.
However, the idea of the cap being faulty did occur to me? Is it simply letting all the air out as the system becomes pressurised? It certainly starts dripping water once the tank is full.

[Edited on 26/2/09 by bilbo]

max level is the join between the two halves?

presumalby that is to whre you fill it up when cold?

at which stage of the running/cooling cycle was the photo taken?

if that is as high as the level gets, you are fine , if it reachest the bottom of the cap, somethung is wrong.

oh, and paint those copper pipes black or blue to match the hose; it'll look far better.

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Originally posted by 02GF74
max level is the join between the two halves?

presumalby that is to whre you fill it up when cold?

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