Overheating V8 90 and viscous coupling

Hi

I have a V8 90 that seems lately to be starting to get a bit warmer than it
should. Is there anyway of testing if the viscous unit is working correctly
- it runs free when cold and the fan seems to be rotating fine when it's
idling and warm if I look under the bonnet.

Thanx

Jay

"Jay Hendry" <[email protected]> wrote in message
news:[email protected]...
> Hi
>
> I have a V8 90 that seems lately to be starting to get a bit warmer than
it
> should. Is there anyway of testing if the viscous unit is working
correctly
> - it runs free when cold and the fan seems to be rotating fine when it's
> idling and warm if I look under the bonnet.
>
> Thanx
>
> Jay

Have you had a peek to make sure the radiator matrix isn't clogged with dead
insects/grass/mud?

Steve

On Wed, 21 Jun 2006 21:41:53 +0100, Jay Hendry <[email protected]>
wrote:

> Hi

How do you do?

> I have a V8 90 that seems lately to be starting to get a bit warmer than
> it
> should.

Cooling system losing any fluid?

> Is there anyway of testing if the viscous unit is working correctly
> - it runs free when cold and the fan seems to be rotating fine when it's
> idling and warm if I look under the bonnet.

aye - that would be a good test.

--
William Tasso

110 V8

"Steve" <[email protected]> wrote in message
news:[email protected]...
> "Jay Hendry" <[email protected]> wrote in message
> news:[email protected]...
>> Hi
>>
>> I have a V8 90 that seems lately to be starting to get a bit warmer than
> it
>> should. >
> Have you had a peek to make sure the radiator matrix isn't clogged with
> dead
> insects/grass/mud?
>

I second that - my Rangie was overheating a bit, so whipped the radiator out
to flush it and removed a forest -load of dead leaves and twigs from in
front of it. My rad was also rotten too, the fins were disintergrating.
One new rad later and everything is now hunky dory!

Paul

"Steve" <[email protected]> wrote in message
news:[email protected]...
> "Jay Hendry" <[email protected]> wrote in message
> news:[email protected]...
>> Hi
>>
>> I have a V8 90 that seems lately to be starting to get a bit warmer than
> it
>> should. Is there anyway of testing if the viscous unit is working
> correctly
>> - it runs free when cold and the fan seems to be rotating fine when it's
>> idling and warm if I look under the bonnet.
>>
>> Thanx
>>
>> Jay
>
> Have you had a peek to make sure the radiator matrix isn't clogged with
> dead
> insects/grass/mud?
>
> Steve
>
>
When the engine is cold it should run free usually you can spin it, warm her
up and stop the engine it should be very stiff to turn if its still running
free then you have a problem - once the engine is running the fan will turn
the whether or not its OK the point of the viscous coupling is it will push
more cool air as the coupling becomes stiffer
Derek

On or around Wed, 21 Jun 2006 21:49:03 GMT, "Derek"
<[email protected]> enlightened us thusly:

>
>"Steve" <[email protected]> wrote in message
>news:[email protected]...
>> "Jay Hendry" <[email protected]> wrote in message
>> news:[email protected]...
>>> Hi
>>>
>>> I have a V8 90 that seems lately to be starting to get a bit warmer than
>> it
>>> should. Is there anyway of testing if the viscous unit is working
>> correctly
>>> - it runs free when cold and the fan seems to be rotating fine when it's
>>> idling and warm if I look under the bonnet.
>>>
>>> Thanx
>>>
>>> Jay
>>
>> Have you had a peek to make sure the radiator matrix isn't clogged with
>> dead
>> insects/grass/mud?
>>
>> Steve
>>
>>
>When the engine is cold it should run free usually you can spin it, warm her
>up and stop the engine it should be very stiff to turn if its still running
>free then you have a problem - once the engine is running the fan will turn
>the whether or not its OK the point of the viscous coupling is it will push
>more cool air as the coupling becomes stiffer

It'll only spin full power once the engine's above normal temperature though
- they're not easy to check for this reason. You could try, on a hot day,
running the engine at standstill at a steady 2500 revs or so, and keep an
eye on the temperature gauge. The fan should at some point lock up - it
might be up near "red" on the dial though. when it does you can hear it
quite distinctly - they make a lot of noise at full speed.

The other clue is that when you start off from cold, it should spin at full
power initially, then run down to idle, IME. you can hear this, too. The
fan will never be actually stationary with the engine running.

However, overheating is more often a rad problem as others have said,
external blockages are easily cleaned off, internal blockages, again IME,
ditch the rad and fit a new one - I've never yet succeeded in clearing one
that's significantly blocked.


--
Austin Shackles. www.ddol-las.net my opinions are just that
"Chuck didn't reply, so George swung round in his saddle. He could just
see Chuck's face, a white oval turned toward the sky.
'Look,' whispered Chuck, and George lifted his eyes to heaven.
(There is always a last time for everything.)
Overhead, without any fuss, the stars were going out"
Arthur C. Clarke, "The 9 billion names of God"

"William Tasso" <[email protected]> wrote in
news[email protected]:

> On Wed, 21 Jun 2006 21:41:53 +0100, Jay Hendry
> <[email protected]> wrote:
>
>> Hi
>
> How do you do?
>
>> I have a V8 90 that seems lately to be starting to get a bit warmer
>> than it
>> should.
>
> Cooling system losing any fluid?
>
>> Is there anyway of testing if the viscous unit is working correctly
>> - it runs free when cold and the fan seems to be rotating fine when
>> it's idling and warm if I look under the bonnet.
>
> aye - that would be a good test.
>

Hi all

Thanks for all your comments

Can't say as I've noticed a noise difference like when it cuts but will
have a closer listen.

The rad itself is clean on the outside and I flushed it out and refilled
last year with no muck or sludge coming out though the coolant hadn't
been changed for quite a few years so I did put a flushing agent in and
ran that through before refilling with antifreeze,

The water level stays fine in the header tank - not having to top it up.

The gauge seems to stay just a needle width above normal when idling or
stopped in traffic when hot and when running normally but when it's
working a bit harder, towing or going up long hills I see it rise to
about halfway between normal and the red section on the gauge (standard
LR 90 temp gauge). OK I realise it could well rise but it never used too.

I'll try running it at higher revs when standing and see if I can hear
the fan lock up and maybe cover the grill with a sack to try and restrict
airflow and see if the fan locks up that way.

Thanx again

Jay

Austin Shackles is spot on.

A healthy viscous fan will engage when you start the engine from cold.
The volume of air it moves causes a roaring noise, which after about 90
seconds will disappear totally.

A worn viscous unit will no shift as much air, causing the temperature
needle to creep higher than centre when stationary or at low speeds.
If the temperature needle falls back when you're running at a constant
speed this also supports your theory that the viscus unit is worn.

Also, is the car overheating, or is the needle between the dead centre
and the red zone? If it's not in the red zone it's not doing any harm,
but we get used to modern cars with needles that sit at 90 degrees all
day.

On Thu, 22 Jun 2006 07:11:18 GMT, Jay Hendry <[email protected]>
wrote:

>"William Tasso" <[email protected]> wrote in
>news[email protected]:
>
>> On Wed, 21 Jun 2006 21:41:53 +0100, Jay Hendry
>> <[email protected]> wrote:
>>
>>> Hi
>>
>> How do you do?
>>
>>> I have a V8 90 that seems lately to be starting to get a bit warmer
>>> than it
>>> should.
>>
>> Cooling system losing any fluid?
>>
>>> Is there anyway of testing if the viscous unit is working correctly
>>> - it runs free when cold and the fan seems to be rotating fine when
>>> it's idling and warm if I look under the bonnet.
>>
>> aye - that would be a good test.
>>
>
>Hi all
>
>Thanks for all your comments
>
>Can't say as I've noticed a noise difference like when it cuts but will
>have a closer listen.
>
>The rad itself is clean on the outside and I flushed it out and refilled
>last year with no muck or sludge coming out though the coolant hadn't
>been changed for quite a few years so I did put a flushing agent in and
>ran that through before refilling with antifreeze,
>
>The water level stays fine in the header tank - not having to top it up.
>
>The gauge seems to stay just a needle width above normal when idling or
>stopped in traffic when hot and when running normally but when it's
>working a bit harder, towing or going up long hills I see it rise to
>about halfway between normal and the red section on the gauge (standard
>LR 90 temp gauge). OK I realise it could well rise but it never used too.
>
>I'll try running it at higher revs when standing and see if I can hear
>the fan lock up and maybe cover the grill with a sack to try and restrict
>airflow and see if the fan locks up that way.
>
>Thanx again
>
>Jay


With this recent spell of hot weather, mine does the usual of engaging
on startup for a few seconds, but if it has been sat in the sun all
day it will continue to drive for quite some time.

Its easy to tell when its driving - the wind noise from under the
bonnet is quite loud !!