M35 Cooling System Overhaul

[scotty nm35]

I fitted the fan shroud after hacking it up. A piece of the shroud must have snapped off and hit the fan, forcing it through the core.

[bigkevracer]

Thread bump.

I'm looking at overhauling mine too, to coincide with installing Scotty's bleed kit when it it available. I'm also looking at upgrading the system.

I've already got a Nismo VQ35 thermostat, and I'll be replacing the radiator and associated hoses.

I've read everything I could find on the topic and what I'm after is some follow up info from people who have upgraded theirs.

What I'd like to know from those who have replaced their radiators already is:

1. For an upgrade which is the better radiator? I'm looking at the Mishimoto unit (2 row, 36mm core), but I did read that Koyo make a similar radiator.
   
2. Those using the Mishimoto with the thermo fans (which I think is just Craig?), are there any real gains?
   
3. Any recommended places to get the radiator? Z1 Motorsports look to be one of the cheaper, at ~AU$430 with hoses and freight.
   

Cheers!

[Daleo]

I have Ian's old gigantor radiator (720mm wide, 420mm high, 52mm thick); which worked admirably with the engine fan. Still running OEM thermostat.

The fan recently packed it, so I'm now running a pair of 14" thermo's in a custom stainless shroud (which is essentially what the Mishimoto shroud/fan set-up is).

I'm working on a temp switch & relay setup at the moment, as the Toyota switch my mate uses; is a bit too hot to run in our system. Just need to find a slightly cooler switch.

These monster fans have no issue cooling the car.

Currently I'm running them on a manual switch; and the difference in response from the engine (in comparison to the viscous fan) is massive!

Revs out much quicker & smoother; especially when ambient temp is warmer.

Worth the hassle IMO, but everyone is different.

What are people paying for Nismo thermostats & maybe a link?

[bigkevracer]

I have Ian's old gigantor radiator (720mm wide, 420mm high, 52mm thick); which worked admirably with the engine fan. Still running OEM thermostat.

The fan recently packed it, so I'm now running a pair of 14" thermo's in a custom stainless shroud (which is essentially what the Mishimoto shroud/fan set-up is).

I'm working on a temp switch & relay setup at the moment, as the Toyota switch my mate uses; is a bit too hot to run in our system. Just need to find a slightly cooler switch.

These monster fans have no issue cooling the car.

Currently I'm running them on a manual switch; and the difference in response from the engine (in comparison to the viscous fan) is massive!

Revs out much quicker & smoother; especially when ambient temp is warmer.

Worth the hassle IMO, but everyone is different.

Thanks Dale.

How much hassle was it then Dale? I've seen temp switches recommended for Nissans, so that side of it shouldn't be too hard?

What else is involved? You make it sound like once it's installed and wired properly it's easy!

Were the thermos really necessary on a radiator that big though? That's a lot bigger than what I've looked at so far...

What about before/after temps?

What are people paying for Nismo thermostats & maybe a link?

I bought mine through Jesse Streeter, looks like it was ~$100 plus shipping (had it sent with some other stuff)

[PN-Mad]

I think mine runs hotter oem, but I went from normal temps in the mid nineties with stock system with the stock fans cutting in at 100 degrees(!).

Now I have mishimoto and nismo thermostat. Normal temps is cold night 77, normal low to md eighties. Fan programmed to kick in at 88. But I'm spoilt with stock twin fans.

[Daleo]

Thanks Dale.

How much hassle was it then Dale? I've seen temp switches recommended for Nissans, so that side of it shouldn't be too hard?

What else is involved? You make it sound like once it's installed and wired properly it's easy!

Were the thermos really necessary on a radiator that big though? That's a lot bigger than what I've looked at so far...

What about before/after temps?

I bought mine through Jesse Streeter, looks like it was ~$100 plus shipping (had it sent with some other stuff)

Mine runs from around 84 deg in cooler weather, to around 92 deg peak.

I'm no electrician, so the wiring & relays took me a bit of time; but it's not brain surgery.

Once I have a correct temp normally closed switch; mine will be great, as the default for the system if anything goes wrong with the switch is fans on.

When the switch opens, it releases an energized normally open relay, which then applies 12v through two 20amp fused normally closed relays.

Possibly would've been better going with a dedicated fan controller, but I can't find one that I'm prepared to pay for.

[scotty nm35]

I have a new one here you could buy cheap Dale, like this one...l

http://www.ebay.com.au/itm/AFTERMARKET-THERMO-COOLING-FAN-CONTROLLER-RELAY-ENGINE-GUARDIAN-WATCHDOG-/180863772124?pt=AU_Car_Parts_Accessories&hash=item2a1c5225dc#ht_6143wt_902

I bought a twin temp reading one instead.

[bigkevracer]

Interesting. I always thought thermo fans were supposed to be more effort than they're worth for road cars. Sounds like it might be the way to go.

Thanks guys!

[Daleo]

I have a new one here you could buy cheap Dale, like this one...l

http://www.ebay.com.au/itm/AFTERMARKET-THERMO-COOLING-FAN-CONTROLLER-RELAY-ENGINE-GUARDIAN-WATCHDOG-/180863772124?pt=AU_Car_Parts_Accessories&hash=item2a1c5225dc#ht_6143wt_902

I bought a twin temp reading one instead.

I've been looking at those Scotty, does it use/come with a thermocouple?

Let me know what you want for it please?

I also estimate that I've added around 50-70 km to my fuel range per tank. No other changes just the fans.

I take it you went twin because of your oil cooler fan?

Edited October 21, 2012 by Daleo

[scotty nm35]

Yeh, I wanted to control the oil temp and the trans temp. The other controller I have should display both temps and switch both thermo's on automatically at a preset temp. Probably not required now the manual is a go ahead.

Does $50 sound good?

[iamhe77]

Mates HKS powered V35 has a custom radiator (same as my old one), coolant mod (did his and mine in the same night) and a Nismo thermostat.

Can't get the damn thing over 75 degrees.

Interesting. I always thought thermo fans were supposed to be more effort than they're worth for road cars. Sounds like it might be the way to go.

Thanks guys!

Do it. Less load on engine and more room in engine bay = win/win

Nismo thermostat can be had on RHDJapan (search under V35 Skyline/Z33 Fairlady - cooling)

[Daleo]

Yeh, I wanted to control the oil temp and the trans temp. The other controller I have should display both temps and switch both thermo's on automatically at a preset temp. Probably not required now the manual is a go ahead.

Does $50 sound good?

Sounds great Scotty; pack it up brother.

Send me some bank details, & I'll cash you up.

[bigkevracer]

Mates HKS powered V35 has a custom radiator (same as my old one), coolant mod (did his and mine in the same night) and a Nismo thermostat.

Can't get the damn thing over 75 degrees.

Do it. Less load on engine and more room in engine bay = win/win

Nismo thermostat can be had on RHDJapan (search under V35 Skyline/Z33 Fairlady - cooling)

Sold. Will do.

What's the optimum operating temp for these things?

Dale, let me know how you go with the fan controller. Sounds like a good idea.

[iamhe77]

What's the optimum operating temp for these things?

Well Osiris doesn't let you do much of anything if it is outside of 80-95 degrees C so I guess, between 80 and 95 degrees!

[pipster11]

whats the go with you guys running the low temp thermostat?

If the engine is designed to run at XX deg why run it at X deg lower? (unless its a track car)

surely your just setting yourself up for hassle with the car running on the cold map and running less efficiently, no?

[PN-Mad]

I think VQs are set up to run hot due to the stricter emmissions regulations. It doesn't mean that the motor enjoys running at 95 degrees coolant and 95 oil temp.

I haven't got my tune with me, but I believe the motor is off cold map by the low 70s. Our cold maps have idle control, ign timing, and four fuel maps to control.

[pipster11]

emissions will play a part but everything nissan would have engineered would have been based around the operating temp of the stock thermostat

[PN-Mad]

they also "engineered" it with a terrible dump pipe, and a turbo that explodes at around 100k kms....

[iamhe77]

they also "engineered" it with a terrible dump pipe, and a turbo that explodes at around 100k kms....

Not to mention a blanking plate between the banks that can create hot spots due to stagnant coolant.

[pipster11]

i'll go ahead and say Renault did those parts