temp in stx550 going hi before fan kicks in

[spiezzy]

hi ti all
just noticed today in my STX550 2011 V9X engine when i was going up a big hill the temp was climbing and reached 110 degrees before the viscose fan kicked in it usually kicks in at around 99 degrees but for some reason it kept going up as soon as the fan jumped into action it cooled straight away any idea what could cause this thanks in advance for your help
cheers Pete

 

[Old.Tony]

You might find that the viscous hub is failing.

To test:

Get the engine to normal operating temperature (drive for 10 minutes). Have someone sit in the driver's seat, pop the bonnet and watch the fan. Have them turn the engine off - the fan should stop with the engine. If it turns a bit after the engine has stopped, the viscous hub is failing.

Remedy: 3 possibilities.

1 (insanity level: max) - purchase a genuine one from Nissan and accept that it won't work properly without their special upgraded wheel nuts and wider brake light bulbs which they'll throw in for free if you fork the $17,028.95 for the new hub (fitting extra). I might be exaggerating just a little.

2 (sensible) - Purchase an aftermarket unit from a place like Brett's Truck Parts on the NSW Central Coast. I did this so that I had two. Service was excellent, delivery very quick.

3 (if you're handy and dare to step in enemy territory) - purchase a bottle of silicone oil from Toyota. Most dealers have it, it should cost around $18. Remove your hub, open it, pour in the bottle of oil, close it, reinstall it. I have done this with mine (once I had a second one), it was easy to do and works perfectly.

I doubt it's the sensors. The viscous hub uses a bimetal strip to activate the valve. Grab a paint stripper gun (heat gun - a hair dryer might work on high heat-low fan) and aim it straight at the metal coil on the front, it should start moving around 80-90 degrees.

 

[tony d22]

Tony, not D40 but my D22 viscous fan still spins after the engine is switched off for several revolutions.
Been doing that since new.

 

[spiezzy]

I did the test that you suggested tony and the fan spins a few times when engine stops I went back up the same hill again today and fan cut in at around 104 degrees today I have ordered a new fan clutch (genuine ) but from NavaraParts in Melbourne $459 with sensor Nissan Kirrawee wanted $980 so when it arrives I will fit it and hopefully solve this issue
thanks again for your help
cheers Pete

 

[tweak'e]

Tony, not D40 but my D22 viscous fan still spins after the engine is switched off for several revolutions.
Been doing that since new.

may not be hot enough for it to engage enough.
when they fail they spin for quite some time.
the other way is they should be a bit stiff when cold as its just dragging on the silicone oil.

 

[spiezzy]

I just went out to do that and yep there is hardly any resistance when turning the fan by hand with engine cold

 

[tony d22]

may not be hot enough for it to engage enough.
when they fail they spin for quite some time.
the other way is they should be a bit stiff when cold as its just dragging on the silicone oil.

Yes it is firm to spin when cold too.

 

[spiezzy]

Problem Solved it was as you suggested Old Tony the viscous fan swapped it out and works a treat thanks again for everybody's help fan now cuts in at 97c all the time

 

[ericcs]

well done!
Fingers crossed, Tony won't swap brands too soon!