bilbo
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| posted on 26/2/09 at 10:59 AM |
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Car running temps
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
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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Mr Whippy
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| posted on 26/2/09 at 11:05 AM |
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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]
Fame is when your old car is plastered all over the internet
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bilbo
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| posted on 26/2/09 at 11:10 AM |
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quote:
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
Yep, this is basically what I'm going to do. I've ordered a switch to use, and I know from connecting the fan direct to the battery, I can
keep the engine at a good temp, so this should work.
I'm just a little concerned that it can't run at the temp it's meant to without too much expansion?
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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Mr Whippy
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| posted on 26/2/09 at 11:13 AM |
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bigger bottle then? is it from the same donor?
Fame is when your old car is plastered all over the internet
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bilbo
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| posted on 26/2/09 at 11:17 AM |
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quote:
Originally posted by Mr Whippy
bigger bottle then? is it from the same donor?
That's the thing, it is from the same donor so should be big enough?
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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02GF74
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| posted on 26/2/09 at 11:31 AM |
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quote:
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.
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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bilbo
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| posted on 26/2/09 at 12:11 PM |
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quote:
Originally posted by 02GF74
quote:
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.
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.
This is what I'm worried about.
The header tank is filled correctly up to just below max.
I initailly had a lot of issues with the EWP, down to a faulty controller. I'm now happy that it's working properly and generating good
flow through the block.
What I am starting to wonder is if it has good enough flow through the radiator? Both the header tank and the turbo circuits both bypass the radiator,
but with much smaller bore pipe, so the majority of flow must be through the rad?. I can probably safely block off the turbo circuit for now, which is
what I'll try next?
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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Ketchup
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| posted on 26/2/09 at 12:43 PM |
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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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02GF74
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| posted on 26/2/09 at 12:50 PM |
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quote:
Originally posted by bilbo
I initailly had a lot of issues with the EWP, down to a faulty controller.
did you run t he car on the road with the bad controller? If so, see ^^^ about headgasket. The signs are not looking good.
Can you draw diagram of you plumbing showing bore sizes?
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bilbo
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| posted on 26/2/09 at 01:23 PM |
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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
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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britishtrident
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| posted on 26/2/09 at 01:27 PM |
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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]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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02GF74
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| posted on 26/2/09 at 01:27 PM |
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quote:
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.
digrams looks ok but what has happned to the heater lines?. you can buy dye that changes colour if there is presence of exhaust gas in coolant.
you say "it soon drops down after you shut the car off."
please quantify by what exactly you mean by "soon".
1 minute or 20 minutes? There may be a clue there.
unless you are living in the ARctic, oh hang on you do,  I would expect the time to cool would be much longe than time taken to heat up.
[Edited on 26/2/09 by 02GF74]
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britishtrident
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| posted on 26/2/09 at 01:35 PM |
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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
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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bilbo
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| posted on 26/2/09 at 01:43 PM |
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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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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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02GF74
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| posted on 26/2/09 at 01:56 PM |
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quote:
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.
but is the fan running? If not, that sounds too quick to lose heat without any forced cooling. Is the water noticeably cooler by then? - you can
grab a hose and feel it.
I am trying to find out if the wter level drops due to water cooling and contracting or some other reason.
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bilbo
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| posted on 26/2/09 at 02:01 PM |
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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.
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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bilbo
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| posted on 26/2/09 at 02:03 PM |
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Also, all the pipes and radiator feel uniformly hot to me, and take a long time to cool down
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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02GF74
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| posted on 26/2/09 at 02:18 PM |
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quote:
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.
so it appears the level drops down in 2 stages - quite quickly in first couple of minute then gradual over a much longer time, maybe 20 minutes?
What shape is the reservoir? Is the shape such that the volume is linear i.e. a cylinder? If it is was connical, the top part is much smaller volume
than the lower part hence you see the rate of volume change change more.
another angle.
1. measure or estimate the volume of liquid in cooling system.
2. esitmate or measure volume of expansion tank.
3. work out the increas in volume for 90 degrees.
see if this matches what you are seeing.
Is the pressure cap working?
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bilbo
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| posted on 26/2/09 at 02:26 PM |
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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]
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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02GF74
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| posted on 26/2/09 at 03:33 PM |
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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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bilbo
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| posted on 26/2/09 at 04:08 PM |
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quote:
Originally posted by 02GF74
max level is the join between the two halves?
presumalby that is to whre you fill it up when cold?
Yes, indeed. However, the pic was taken before I ever started the engine, having over filled it. Sadly it does fill all the way to the top of the tank
when over 90-95 degs but it does drop down again to more like the level in the pic if I fire up the fan manually while the engine is still
running.
I'm going to have a futher play with it tonight with all the suggestions made on this thread....see what I can do.
Many thanks again for your help.
[Edited on 26/2/09 by bilbo]
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Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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