Cooling fan clutch

Nissan Navara Forum

Help Support Nissan Navara Forum:

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
Howdy Nav Heads,

Lately my coolant temps have been creeping just a little higher under load than I'd like. It's nothing serious yet, but it's still Winter in Tasmania, so a mild issue now could be serious in February.

So I've begun to observe & troubleshoot.
First step was to drill & file out two sections of the plastic grill around the Nissan badge for more airflow (it's neat, undetectable...and I had the grill off anyway)

Second is to order a new thermostat next week.
Fairly easy, affordable insurance.

Today I checked the cooling fan clutch.
When I switched the motor off at op. temp the fan did not stop quickly...it took quite a few seconds to spin down (not good).
I restarted the motor & held a piece of fairly stiff plastic card against the spinning blades, and I couldn't stop the fan (good).

So I need a third method to prove the clutch...?
Anyone had the clutch on the workbench?

Next step will be winch controller relocation.
And/or new radiator.
 

tweak'e

Moderator
Staff member
Joined
Oct 21, 2008
Messages
5,313
Reaction score
203
Location
New Zealand
sorry i don't do much with D40's.

with fan clutch check that its stiff to move when cold. but it doesn't sound to bad if it takes a few seconds to stop.
one thing to keep in mind is thermostats are there to keep the engine hot. they are not cooling devices.
airflow is rarely a problem unless you have a dozen spotlights in front of the grill.
the main culprit is typically the radiator. they get blocked up or fins erode. 2nd is water pump.
if its an auto a common mod is to have a separate trans cooler.
 

johnl56

NF Supporter
Supporting Member
Joined
Oct 29, 2020
Messages
67
Reaction score
18
Location
Tasmania
Thermostat first and see how it goes. Easy fix, as far as the fan clutch goes if you can't stop it turning then it is working, I haven't looked at mine when it stops but it is movable with effort. And I don't know if they can be taken apart. If it is the clutch then have a look at the wreckers.
 

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
sorry i don't do much with D40's.

with fan clutch check that its stiff to move when cold. but it doesn't sound to bad if it takes a few seconds to stop.
one thing to keep in mind is thermostats are there to keep the engine hot. they are not cooling devices.
airflow is rarely a problem unless you have a dozen spotlights in front of the grill.
the main culprit is typically the radiator. they get blocked up or fins erode. 2nd is water pump.
if its an auto a common mod is to have a separate trans cooler.
Fan runs on for quite a few seconds after shut down. I might take a video & post it up...

Thermostat - I agree. They stay closed until the block is warm & then open for flow. And some engines will run hotter with the thermostat removed because coolant moves around too fast to cool down in the rad.
But I've heard they can fail in an intermediate position (??) Which makes trouble-shooting harder.
My Nav takes ages to warm up (I know, it's a diesel idling with no load, so expected)....but I mean AGES. And now it's getting hot-ish (<= 97 deg) running up any sort of incline with no trailer, nothing in the tub, and just me in the cab.
Externally, the radiator looks mint. Bugger all folded fins, no crusty leaks. Quite clean.
But I guess it could still be scaled-up inside.

Yes I do have two small spotties out front. But they are spaced apart and don't crowd the centre area too much. (see attached pic)
BUT.....right in the middle is the big old winch controller. Which brings me to my next question....

Has anyone relocated their winch controller successfully? I've seen a few comments about it but I can't remember where.
I'm wondering if I find somewhere in the bay for it? Or on the backside of the main bull bar next to the winch itself? I don't reckon it's a half-a-day job either.
How much water would it tolerate if it's lower? (creeks and bogholes etc)
 

Attachments

  • Nav grill blanked.jpg
    Nav grill blanked.jpg
    2.7 MB · Views: 0

Horatius

Misanthrope
Joined
Sep 30, 2016
Messages
744
Reaction score
196
Location
Aus
It would be highly unusual for a thermostat to cause something like this afaik, they usually work or they don't (ie. car boils). Not impossible though, I suppose.

I know nothing of D40, but I know on the D22 winch controller and lights don't make any noticeable difference. The winch itself (and design of bull bar to some extent) makes quite a difference though. Compared to the standard alloy bar, they consistently run 5-10 deg C hotter with steel bull bar and winch fitted. It blocks off a lot of air flow. Not really a problem though as they run reasonable cool to begin with.

Assuming these things have been on the car for a while and you've only recently noticed higher temps, it's unlikely they will be the problem.

The most likely problem if you are noticing your temps running a bit higher, is the radiator. There's no way to tell if they are restricted by looking at the outside. A radiator place will be able to test it and let you know if its restricted (and by how much), but if you don't find anything else obvious it's probably easier just to change it. The problem is, as you say, you don't want to be flying along the freeway in summer and have it overheat. Often by the time the gauge indicates this it's already too late and you'll be up for a new head.

Don't know about the water pumps on these (seems extremely rare to have water pump problems on the D22) but corrosion could be a problem there also, especially if it hasn't been serviced regularly/properly.
 

Horatius

Misanthrope
Joined
Sep 30, 2016
Messages
744
Reaction score
196
Location
Aus
ps. ^ By "D22" I mean the 3 litre version. Know nothing of the 2.5 motors, but same logic applies.
 

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
Thanks Horrie.
When you look at the ute front-on (in person), there's still plenty of room around the accessories and under the bar for air to flow through....so it's a bit of a head-scratcher.

Given that I'm planning to do lots of camping and exploring this summer, and I need to tow our excavator soon as well, I've decided to do a bit of everything. I don't want to be worrying about the temps all the time....and Tassie is not very flat.

I'm going to order a rad, a thermostat AND relocate the winch controller as well. I want some cooling "headroom".

It's just the fan clutch that I'm not sure about. I think it might be crook....but haven't proven it.
Was hoping someone had taken theirs apart?
(I read @johnl56's link. Much appreciated.)
 

fuzzylogic

Member
Joined
Dec 18, 2017
Messages
57
Reaction score
17
Location
Yarrahapinni
Thanks Horrie.
When you look at the ute front-on (in person), there's still plenty of room around the accessories and under the bar for air to flow through....so it's a bit of a head-scratcher.

Given that I'm planning to do lots of camping and exploring this summer, and I need to tow our excavator soon as well, I've decided to do a bit of everything. I don't want to be worrying about the temps all the time....and Tassie is not very flat.

I'm going to order a rad, a thermostat AND relocate the winch controller as well. I want some cooling "headroom".

It's just the fan clutch that I'm not sure about. I think it might be crook....but haven't proven it.
Was hoping someone had taken theirs apart?
(I read @johnl56's link. Much appreciated.)
the test on the fan clutch is to see if it still spins for a bit when you turn the ute off, if it still does, the viscous oil is depleted. You can buy some from a Toyota dealer (it's the same viscous oil), no one else seems to sell it. take apart the fan clutch and re-fill with new oil. It comes in small bottles about 25 or 50mL, can't remember, it's an easy job, just a bit fiddly. From memory there's you tube tutorials on replacing the oil. It's a silicon based oil, about $25/bottle. Hope this helps...
 

Horatius

Misanthrope
Joined
Sep 30, 2016
Messages
744
Reaction score
196
Location
Aus
What driving conditions cause it to get hot?

The common wisdom afaik is that if your car is getting hot at highway speeds it'll be a restricted radiator. At any rate, from experience, it's overwhelming likely to be that. The wind through the radiator at that speed should be enough to keep it cool.

At low speeds if it gets hot, such as in stop start traffic or steep off road stuff, it could be because the viscous fan is not drawing in enough volume off air (among many other things).

Though I have noticed in the past there are nearly as many explanations for how these things work and how to diagnose them as there are people lol. It can be vague, subjective and difficult.

Are they very expensive? It might be worth just changing it. Then you'll know it's definitely alright.
 

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
What driving conditions cause it to get hot?

The common wisdom afaik is that if your car is getting hot at highway speeds it'll be a restricted radiator. At any rate, from experience, it's overwhelming likely to be that. The wind through the radiator at that speed should be enough to keep it cool.

At low speeds if it gets hot, such as in stop start traffic or steep off road stuff, it could be because the viscous fan is not drawing in enough volume off air (among many other things).

Though I have noticed in the past there are nearly as many explanations for how these things work and how to diagnose them as there are people lol. It can be vague, subjective and difficult.

Are they very expensive? It might be worth just changing it. Then you'll know it's definitely alright.

OK good question....

Bear-in-mind the following observations are during a Tasmanian winter. Ambient temps are in the mid-teens at their warmest....but often high single digits.
And ute is unladen. Just me (100kgs), and the fiberglass canopy. Tyres are 265/65/17.

At idle it consistently sits at 91 or 92 degrees no matter what. And it will return to this temp quite quickly after pulling up & idling for a minute. So the system can shed heat as soon as load is removed.
As mentioned, at stone cold start up it can take 20+ minutes idling to get to 80 degrees.

Cruising around town, from traffic light to traffic light, it will move between 91 and 94. I very rarely use any more than 3000 rpm.

Freeway, cruising 100 to 120km/h, flat gradient, around 92 to 93 degrees. But this condition has started to creep up a little lately.

Freeway, up-hill 100km/h in 5th or 6th. Temp quickly jumps to 97 or 98 degrees. And the increase is fast and the hill doesn't need to be very long. This is the condition that has caught my eye.
If we fast-forward to Summer, ambient at 28+ degrees, ute loaded with tools, bikes, people, trailer..... plus long hill at 100km/h....and I think she'll be well over 100 degrees.
Now, I know the occasional trip to 105 degrees isn't going to kill my engine. But I think my problem is a loss of "head room" in the system.

What started this thread was me thinking the fan was the best place to point the finger.
But the more I think about it, the more I think the rad has to go.
(or get a professional diagnosis and /or flush out?).
 

Horatius

Misanthrope
Joined
Sep 30, 2016
Messages
744
Reaction score
196
Location
Aus
Yeah, the coldest winter I ever spent was a summer in Tassie lol.

That does sound a little high, especially just idling in the 90's. Though I don't know much about that model so could be wrong, perhaps someone with experience of your model will know how close it is to normal. How regularly has it been serviced? It wouldn't hurt to get the radiator looked at, or replaced.

These are a worthwhile investment also. Engine Watchdog. Engine Guard. The alarm could save you money, stock gauges are rubbish and basically let you know when you've done the head.

I've also got a low water alarm (float switch in the top radiator hose) on my D22 .
 

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
OK, I'm elbows deep in the cooling system today.
Rad is out & down with the local guru for a flush/inspection/test.

I just pulled the thermostat housing & this is how I found it.
Does the orientation matter?
I was of the understanding this would be incorrect/upside down?
 

Attachments

  • 20221003_141552.jpg
    20221003_141552.jpg
    1.4 MB · Views: 0

BarneyB

NF Supporter
Supporting Member
Joined
Feb 15, 2022
Messages
177
Reaction score
48
OK update...

This last week I took the radiator out of the Nav & had it flushed & tested with the local Rad specialist. It passed with flying colours. Full flow from every tube. So I cleaned the air side & put it back in the ute.
I replaced the thermostat with a new Tridon "high flow" unit.
I flushed the system with cooling system chem before disassembly.
I removed the thermo fan clutch & disassembled. Inside it looked great. Oil was clean & more importantly, present. I tested the bi-metal coil with a heat gun & it opened the internal valves no-worries. I added half a bottle of new oil (about 6-7ml) and boxed it back up.

I also fitted a Tillix boost control valve & needle spool valve and have just got back from a test drive & tweak. I figured the Tillix might help lower engine temp a little, via EGT's...on top of the other benefits it brings.

So...
It's too early to say the high coolant temp issue is fixed because I need to do some more highway miles....particularly uphill.
But tonight I did a short, flat, highway drive at 110km/h for about 5 minutes. The coolant temp rose briefly to 92 degrees and then stayed around 90-91 degrees. Ambient temp was around 12 degrees.
Driving around the subs from red light to red light it seems to run a little cooler....stays in the upper 80's.
It's always been highway driving at steady state throttle, uphill, that causes the spikes. Not stop-start around town.

Since the radiator was not the smoking gun I thought it was, I now have to find other things to eliminate...
So I'm leaving a question mark over the fan clutch. Not sure how to prove convincingly it's good....or buggered...?
And the winch controller might be the problem...but again, might not. It has an upward deflective angle to it that might be working like a mini-spoiler at high speed & pushing air up over the bonnet....right in the middle of the rad.
Local Rad guru reckons if the heater in the cabin is hot, then the water pump is OK. Cabin heater works like a furnace. No other evidence that the water pump is tired...
 

joe2006

Member
Joined
Feb 21, 2011
Messages
1,612
Reaction score
41
Location
Central Victoria
If you didn't already know and perhaps a little useless information? To test thermo fan -
Turn on ignition (don't start)
Push drivers door switch 10 times in 20 seconds
Turn ignition off and turn it straight back on
The BCM will go through a series of tests including wipers, lights and thermo fan at both speeds.
Unfortunately doesn't help with the clutch fan operation
 
Last edited:

Latest posts

Top