A Reminder To Check Your Radiator Fan For Cracks And Stress Fractures

[flavzz]

I was just doing some routine maintenance and discovered some serious stress fractures and 2 big cracks in the radiator fan base. Obviously if this let go it could cause some serious collateral damage (radiator/hose/water pump/belts etc)

Many of our cars are at the age where plastic parts have experienced numerous heat and stress cycles. The radiator fan is one of the most stressed plastic components in the engine bay. Check not only for cracks but discolouration which is indicative of plastic deformation inside the part.

So take 5 minutes to check yours and replace if necessary. It could save you a lot more than the cost of the fan.

[Got a Pulsar]

Absolutely!

I found similar on my R31 Rad Fan. (25 years old)

Replaced with a fresh GTR Fan.

[colourclassic]

GKTech make a nice aftermarket fan which also offers higher flow as a benefit.

[Ben C34]

GKTech make a nice aftermarket fan which also offers higher flow as a benefit.

With mixed results. Certainly not everyone that's used them is happy.

[GH05T]

also they are loud as fark

[Sparks]

That replacement GTR fan looks the biz! nothing better than a factory upgrade

[Victory]

Cracking on Skyline fans is a common problem (I have more cracked ones than good ones on my cars) and if they let go a high revs they can do some serious damage.

I have seen factory bonnets with major damage from fans letting go - by comparison an aluminium or fibre glass bonnet would just be mince meat with the same impact.

GKTech make an aftermarket fan that moves quite a bit more air volume but it does have its drawbacks. Moving more air generates more noise so it depends on your application. For a normal street car the noise can be a problem but if you have a modified car where engine temps are an issue then they could be the answer to your situation.

[Got a Pulsar]

With mixed results. Certainly not everyone that's used them is happy.

Mat, 34GeeTeeTee I believe was not happy with the GKTech.

Not enough Cooling.

[flavzz]

I think factory ones are best for street use. A friend installed the gktech one and then promptly removed it due to the noise.

[jiffo]

9-blades, would that be an R33 GTR fan? Think the R34 GTR has 8-blades?

Interested to know if the fan noise and cooling are an improvement over the old R32 GTR's style.

[Daleo]

The Gktech fans are not a fantastic upgrade for RB or VQ engines as Mattgeeteetee and I both found.

The VQ25det fan is visually almost identical to an RB25det fan, so the shroud clearance and depth are essentially the same. I was also using a brand new Nissan fan clutch.

The gktech fan is identical in dia to the stocker

For starters; LUDICROUSLY loud!

The fan could maintain control over the cooling system whilst moving (mid 80's) (even slowly) but as soon as the car was stationary, the fan would slowly lose control of temperature over about 5 min, until it got to around 95 degrees; then it would skyrocket over 110 degrees in less than 30 secs.

This was using a temp reading from the ECU temp sensor on a perfectly bled cooling system with a Nismo thermostat and brand new 42mm thick dual pass Mishimoto radiator. All in mid 20's ambient temperature; so nothing silly at all.

Change NOTHING but the fan and clutch; cruising temps dropped to 78 deg, and never rose above 86 degrees regardless of how long I sat stationary in traffic. As soon as I start moving; temps drop quickly back to the low 80's.

It isn't silent, but no clutch fan is.

Matt's experience was extremely similar to mine.

They obviously work on SR's, but they are 20mm larger dia than the stock fan; tightening the clearance to the shroud may improve flow, but I don't rate them at all.

[hardsteppa]

Thats interesting Daleo, i have one on an rb25 and am in Brisbane where at the moment, friggin hot, and often is. I've had no oheating issues and it holds the same spot on the temp gauge. I don't have a digital gauge but when i have monitored temp via consult after drag runs, the temp stays the same/ even as with the stock fan. It is bloody loud tho lol. From your report it might ve worth doing more temp datalogging though.

[MBS206]

I would be more curious to see how the GKTech goes on a standard clutch.

[Daleo]

Thats interesting Daleo, i have one on an rb25 and am in Brisbane where at the moment, friggin hot, and often is. I've had no oheating issues and it holds the same spot on the temp gauge. I don't have a digital gauge but when i have monitored temp via consult after drag runs, the temp stays the same/ even as with the stock fan. It is bloody loud tho lol. From your report it might ve worth doing more temp datalogging though.

With regard to the sensitivity of the dash temp gauge; mine (NM35 Stagea) sits in the same spot, 1 needle width below halfway.

It is exactly the same from 73 degrees to 116 degrees.

When bleeding the cooling system the temp spiked briefly to 123 degrees ( recorded as peak hold on Greddy Informeter) and the gauge only rose one graduation.

I believe that the gauge is quite non-linear in the "allowable range" but once you go outside; it ramps aggressively to get your attention.

I have no idea how this relates to the RB gauge.

[Daleo]

I would be more curious to see how the GKTech goes on a standard clutch.

Gktech make a CNC'ed billet adaptor to suit the RB Viscous clutch. Around $20 from memory.

[Jordy32]

With regard to the sensitivity of the dash temp gauge; mine (NM35 Stagea) sits in the same spot, 1 needle width below halfway.

It is exactly the same from 73 degrees to 116 degrees.

When bleeding the cooling system the temp spiked briefly to 123 degrees ( recorded as peak hold on Greddy Informeter) and the gauge only rose one graduation.

I believe that the gauge is quite non-linear in the "allowable range" but once you go outside; it ramps aggressively to get your attention.

I have no idea how this relates to the RB gauge.

I have a Yahsio factory gauge (which uses the ECU sender in the coolant neck) in my car and from about 60 degrees up to about 100 the needle doesn't move at all

Like you, while bleeding it i must've caught a hot air bubble and it spiked to 115 or so and the needle, much like yours hardly moved at all

Take from that what you will, i guess that's why we run aftermarket gauges right?

[Jordy32]

As for the GKtech fan, like others; I've heard great things for SR's, but not RB's - Stock works perfectly for me, no plan on changing it.

I will however check for cracks or hot spots when i get home after reading this so thanks for the tips!

[niZmO_Man]

Most of our cars have the temp gauge 'normalised' so it appears at half way within the operation temperature range.

[TurboTapin]

I noticed a few cracks in my fan today, which lead me to this post. Has anyone actually seen a fan explode? Is the GKTech replacement still no bueno?

[GTSBoy]

I have seen the aftermath of a rotten old stock fan. It took apart the shroud, wrecked some other stuff (PS or A/C, IIRC) and damaged the bonnet. Not ideal.

Sometimes they die more gracefully. Sometimes they live for years and years looking like they should come apart.

The GKTech fan is not different to how it ever was. At least as far as I know. Whether it is any good or not is more a question of what climate you're using it in. In Canuckistan it seldom gets hot enough for the capability of the fan to matter as much as it does here in Fourex. So you should be able to use it without too much concern. You can always sell it to a driftkid in an S14 if you don't like it.