A couple of cooling system questions D2 V8

[CraigE]

Hi all I have a couple of questions about thee D2 V8 cooling system.
First when should the thermo fan kick in on these. I brought it up to temp and turned the air con on today and it did not kick in? Any usual issues to check?
Second one is i had what appeared to be a coolant leak but cannot find it now. Started with a few drops of coolant about centre of engine on ground. All I can find around the engine is a small pool of coolant just forward of the valley cover. The throttle body cooling block was recently changed. Is it possible that it is residual from this or likely a water pump? I would have thought if a water pump it would be fairly visible.
Cheers
Craig

[ballbag]

Puddle on top of engine likely from the throttle body. Delete it if it's still leaking.
Stick head under front of engine and look up. Water pump has small weep hole to warn of failing bearing. It will drip from pump down front of motor and likely along oil filter.
Another spot to check is RHS (driver's) side of fire wall. Coolant overflow pipe dangles in the breeze there and can splash on firewall. If coolant was topped up/bled when throttle body block was replaced it may just be settling back to a happy level and venting the excess.
Best course of action is to clean up any spills/leaks so you can identify new leaks/overflow after each drive.

[CraigE]

Puddle on top of engine likely from the throttle body. Delete it if it's still leaking.
Stick head under front of engine and look up. Water pump has small weep hole to warn of failing bearing. It will drip from pump down front of motor and likely along oil filter.
Another spot to check is RHS (driver's) side of fire wall. Coolant overflow pipe dangles in the breeze there and can splash on firewall. If coolant was topped up/bled when throttle body block was replaced it may just be settling back to a happy level and venting the excess.
Best course of action is to clean up any spills/leaks so you can identify new leaks/overflow after each drive.

Not throttle body, just been replaced and no weeping from there.
Thinking more likely water pump, but no tell tale signs at all. Will keep an eye on it.

[Chops]

Craig, when I had a leak in mine, I was given some "very bright green" coolant to put in and check where the leak was coming from.
Mine ended up being at the pump, which I replaced and then all good.
If your at that point, be sure of which length bolts go in which holes. If I remember correctly there can be issues putting long bolts in short holes.

[Pedro_The_Swift]

The thermo kicks in at first start up,
you will hear it,
at start up is the only time I hear mine,,

with the windows up/aircon on/ music playing/86 thermostat its not an issue,,

[ozscott]

I hear mine for about 2_3 seconds when accelerating away from stationary if the coolant temp has reached say high 80's. Cheers

[Pedro_The_Swift]

front and centre, hose from coolant res attaches to engine, just another reason to go green;)

[CraigE]

OK then this one has a fault or is cactus, will run 12v power direct to it to test.
Cheers
Craig


The thermo kicks in at first start up,
you will hear it,
at start up is the only time I hear mine,,

with the windows up/aircon on/ music playing/86 thermostat its not an issue,,

[Defender Mike]

My son in laws D2 V8 is also losing coolant. We picked this one up in Sydney a year ago with only 50 thousand ks genuine kilometers on it. It started overheating recently i can see coolant near the water pump and on the left side engine mount. It looks like it may be a head gasket front left side bank.
Does anyone have recent costings on getting the head gaskets replaced. Not sure if its worth the effort. Pitty because otherwise its a pretty good car now only 70 k on thr clock. :(

[CraigE]

My son in laws D2 V8 is also losing coolant. We picked this one up in Sydney a year ago with only 50 thousand ks genuine kilometers on it. It started overheating recently i can see coolant near the water pump and on the left side engine mount. It looks like it may be a head gasket front left side bank.
Does anyone have recent costings on getting the head gaskets replaced. Not sure if its worth the effort. Pitty because otherwise its a pretty good car now only 70 k on thr clock. :(

Left side looking at the car or from inside (driver or passenger) There is a drain plug in that area of the block on both sides that could be weeping, check that first. Could also be the water pump. Could also be a Core/Welsh Plug. Unusual to leak coolant if a head gasket, usually will burn it off or end up in the oil but can leak from the ends if a particular gasket is used (cant remember brand). Head gaskets on these are not that difficult to do, no harder than any v8 Holden Ford or V6 Holden. Hardest bit I found was getting the valley cover rear gaskets right. It is worth the effort, you could do it in a day, however if you need to take to a mechanic not sure, depends on what you think its worth. You can get the gasket sets for under $100 for these from OS plus $25 freight, so that cost plus coolant and maybe new thermostat a little over $220 and a days labor. Cost from Australian retailer may be around $200-$220 for the kit.
Cheers
Craig

[Defender Mike]

Could be that drain bolt Craig thanks for the info.:)

[Defender Mike]

Looks like its blown both head gaskets front & rear plus the pump may have a leak as well. I will call TRS for a kit price.:o

[CraigE]

Looks like its blown both head gaskets front & rear plus the pump may have a leak as well. I will call TRS for a kit price.:o

Try Karcraft for a kit.

[Pedro_The_Swift]

or, one of our Vendors;)
http://www.aulro.com/afvb/verandah/233363-easter-your-doorstep-get-you-parts-now.html

LOTS of posts on V8 head gaskets,,
read up before buying,,

[CraigE]

Well, thermo fan runs when putting power straight on (wire pins 30/87 on relay) so now to work out why not kicking in, maybe relay or BCU??
Also no leak found so may be a head gasket leaking into exhaust. No coolant in oil or under oil filler cap. A little bit of moisture in the exhaust but a lot of petrols do this all the time, may need to do a pressure check of some sort.
Cheers
Craig

[ballbag]

I'm confused. Are you losing coolant?

Fan is belt driven...think the relay you're looking at is for cabin fan.

[ballbag]

Or maybe not! Book says 'fan motor is operated by cooling fan relay....'

What the?

[ballbag]

In 5 years of D2 ownership I've never noticed the electric fan infront of the radiator. Whoa. This wild.

[CraigE]

I'm confused. Are you losing coolant?

Fan is belt driven...think the relay you're looking at is for cabin fan.

D2 has a thermo fan as well. Asked two questions 1 re thermo and another re a leak, think more likely head gasket into exhaust now, maybe. Yes losing coolant.

[lewy]

is the aircon actually working\switched on.I presume you are talking the electric fan

[Pedro_The_Swift]

D2 has a thermo fan as well. Asked two questions 1 re thermo and another re a leak, think more likely head gasket into exhaust now, maybe. Yes losing coolant.
easist way to tell is to watch for steam on startup,,
mls and 100lbs,
damn the torpedoes!:D

[CraigE]

Only very minor steam, not really noticeable. I would say minor leak in gasket, but obviously will get worse.


easist way to tell is to watch for steam on startup,,
mls and 100lbs,
damn the torpedoes!:D

[CraigE]

Yep air con is working, just fan not kicking in.

is the aircon actually working\switched on.I presume you are talking the electric fan

[CraigE]

For the thermo thinking maybe temp probe, have bridged the relay so it comes on when ignition on for the time being.

[CraigE]

OK found some interesting info today regarding the D2 thermo fan.
Next question is this for all D2s including Australia?
Most have indicated that their thermo fan kicks in on start up and runs pretty much all the time.
This seems to contradict that.
Cheers
Craig
DESCRIPTION AND OPERATION
4.122 DISCOVERY
Cooling Fan
Cooling Fan Description
The cooling fan is located on brackets forward of the radiator. The fan motor is
operated by a cooling fan relay controlled by the Engine Control Module
(ECM). The main relay supplies a feed to the coil of the cooling fan relay. A
permanent feed is supplied to the coils of the main and cooling fan relays
located in the engine compartment fusebox. On V8 models a coolant
temperature sensor is located in the inlet manifold, on Td5 models the sensor
is located in the outlet housing.
The ECM controls the operation of the main and cooling fan relays. At a preset
temperature the ECM receives an input from a coolant temperature sensor
above the values stored in the ECM. The ECM logic enables the earth path for
the coil of the cooling fan relay. The fan motor then gets a feed from the closed
contacts of the cooling fan relay.
When the engine temperature falls, the sensor gives an input below the values
stored in the ECM. When the input from the coolant temperature sensor low,
the ECM interrupts the earth path to the coil of the cooling fan relay. The
contacts of the cooling fan relay open, this action breaks the feed to the cooling
fan motor, and the motor stops. The cycle will start again when the engine
coolant temperature rises and the sensor sends a high input to the ECM.
The ECM has an engine off function, when the ignition is turned off the ECM
logic goes into a watchdog routine and monitors the coolant temperature for
approximately seven to ten seconds. If the coolant temperature is still high,
over 100 ?C (212 ?F) V8, 110 ?C (230 ?F) Td5, the ECM logic can control the
operation of the fan motor.ഊDESCRIPTION AND OPERATION
DISCOVERY 4.123
On V8 engines the ECM will only enable the fan if the inlet air temperature is
over 60 ?C (140 ?F). The ECM will allow the fan to run for a maximum of ten
minutes, however the ECM continues to monitor the coolant temperature. The
ECM logic will stop the fan if the coolant temperature is below the acceptable
values stored in the ECM. To prevent a flat battery, the fan will be stopped
(regardless of coolant temperature) if the battery voltage falls to 12 V.
Cooling Fan Supply
Circuit supply
A permanent feed from the battery positive terminal is connected by an R wire
to the engine compartment fusebox. A feed from this wire is connected to the
contacts of the main relay and also to fuse 13. The feed passes through fuse
13 and to the inertia switch on a NB wire. The feed from the inertia switch flows
on a WG wire to the engine compartment fusebox and is connected to the coils
of the main relay. in this condition the coil and contacts of the main relay
receive a permanent supply.
The permanent feed from the battery on a R wire to the engine compartment
fusebox is also connected via fusible link 1 to fuse 5. From fuse 5 the
permanent feed is connected to the contacts on the cooling fan relay. In this
condition the contacts of the fan relay receives a permanent feed from the
battery via fuse 5.
Main relay - ignition supply
When the ignition switch is a position II, the ECM switches on the earth path for
coil of the main relay. Current flows through the coil of the main relay and flows
on a UR wire to pin C0635-23 V8/C0658-21 Td5 on the ECM. With the coil of
the main relay energised the main relay contacts close, power is now available
to the coil of the cooling fan relay, via the closed contacts of the main relay.ഊDESCRIPTION AND OPERATION
Cooling Fan Operation
V8 engine
The engine coolant temperature sensor sends an input on a G wire to pin
C0636-22 on the ECM. The engine coolant temperature sensor is earthed on a
B wire to pin C0636-21 on the ECM.
When the coolant temperature is high, the value of input from the coolant
temperature sensor causes the ECM logic to switch on the earth path for the
coil of the cooling relay, on a GW wire to pin C0636-31 on the ECM. With the
coil of the cooling relay earthed the coil is now energised. The cooling relay
contacts close and current flows on a BN wire to the cooling fan motor.
Td5 engine
The engine coolant temperature sensor sends an input on a KG wire to pin
C0158-7 on the ECM. The engine coolant temperature sensor is earthed on a
B wire to pin C0158-18 on the ECM.
When the coolant temperature is high, the value of input from the coolant
temperature sensor causes the ECM logic to switch on the earth path for the
coil of the cooling relay, on a PB wire to pin C0658-4 on the ECM. With the coil
of the cooling relay earthed the coil is now energised. The cooling relay
contacts close and current flows on a BN wire to the cooling fan motor.
All models
The current flows through the cooling fan motor to earth header C0018 on a B
wire. The cooling fan motor will operate as long as the ECM receives a high
signal input from the coolant temperature sensor. When the coolant
temperature is low, the ECM logic interrupts the earth path to the coil of the
cooling relay. The contacts of the cooling fan relay open, the fan motor power
supply is now broken and the motor stops. The cooling fan will cycle on and off
as the coolant temperature rises and falls.

[ozscott]

My thermo doesn't run all the time as standard but I made it run when the AC compressor comes on... Bit more control. And in case people say it would interfere with air flow on the highway it doesn't make 1 degree difference in coolant temp at those speeds..

Cheers

[CraigE]

My thermo doesn't run all the time as standard but I made it run when the AC compressor comes on... Bit more control. And in case people say it would interfere with air flow on the highway it doesn't make 1 degree difference in coolant temp at those speeds..

Cheers

Yeah, I have my Defender set up with twin Davies Craig Thermos. One set up to come on at temp in the top hose, the other to come on whenever the air con is on. They way I have it set up at present may be better for Australian conditions anyway. There is plenty of room for second thermo so maybe worth considering. The way I read it is it kicks in at a certain temp say 96deg C and cuts out when below or at highway speeds over 100kmph. Most are saying their fans kick in straight away which is in conflict to the previous doc I posted. If I can get my Nanaocm working properly again I will hook up and see what the computer says.
Cheers
Craig

[CraigE]

Some good news, think the primary issue is just a water pump. Found it pooling slightly on the valley cover,initially thought one of the hoses, but when cleaned off and some clear water in the same spot when engine running could spy just a small trace of coolant oozing out. While running not much, but seems odd after the engine has cooled it pushes out more.

[Geoff86RRC]

Greetings
PROBLEM
Four years I have struggled with my V8 overheating. I bought an OBDC and plugged it in and used my iPhone to monitor the temperature. I did this because the gauge is completely useless. It used to run at 105 to 110 degrees. After a new radiator it got hotter. On the highway, on hills at night in the cool it was always hot hot hot. I replaced the viscous fan. It had extra fans, everything was checked and changed out to no avail. I also bought an engine watchdog and found that it was running about 3 degrees below that showing from the OBDC (which comes from the actual temp sender)
SOLUTION
Murray, at Jagrover Spares in Brisbane got sick of all of the engines overheating and blowing and liners slipping and head gaskets popping and radiators popping and I even saw one of the thermostats with a huge split in its side due to excessive temperature and pressure. He has totally redesigned the coolant flow and he now uses an in-line thermostat running at 82 degrees, with a slight drillhole modification. He has done away with the stupid BMW heart valve monstrosity, and my D2V8 now sits on 84 to 89 degrees. I cannot thank him enough and urge all D2 and P38 owners to contact him. (07) 3857 5763. He has actually worked it out and my vehicle is fantastically cool just like the old ranges and disco ones of yesterday. This works for p38s too. He has the hoses and inline thermostat that fit and work. Hallelujah.