Installing a Volvo Electric fan on a 3.5L Montero

[Monterorider]

No problem. It's a very valid question.

To experience the overheating, try going up a steep grade in loose dirt (not even slipping) for ~5-10min while temps are +95f at <5-10mph @ 2-3Krpm then slow down as though there is 4x4 traffic ahead of you but keep moving up hill. You'll understand very quickly why this upgrade is very much desired.

At that speed/rpm the fan is turning too slowly and there is insufficient airflow to cool the coolant in the radiator plus your AT will be getting VERY HOT which will just add more heat to the radiator. I can almost guarantee you will overheat and quickly appreciate the benefits of an Electric Fan.

Alternatively if you stay on relatively level terrain (deserts, etc.) then you probably won't encounter this (unless it's August and you're in AZ).

HTH

With properly functioning clutch stock fan will move a lot of air even at idle. Again I doubt given electric fan will do that much better. Guess could try to find specs. I hear 4000 cfm @ 2200 RMP for Ford/Volvo fan. That's max hard set limit of electrical motor v comparatively limitless power of mechanically driven fan. Mechanical fan CFM will depend on engine speed. Easy enough to compare volume it can push. Outside diameter is about the same? I don't have one at hand. To get fan speed compare diameter of pulleys. (main v one driving fan clutch) Say about twice. Hence at idle stock fan would be running at around 1300-1500 RPM pushing about 2/3- 3/4 of electrical fan volume. Yes seemingly worse. But! Bump you RMP just a bit up to 1000 and you are about equal go even a bit faster at like 2000 RPM stock fan will blow electrical away. Pun intended. It will push like more and more air. Simple math. So long one maintains fan clutch so fan locks hard. Therefor when you work hard your engine like pulling a trailer at slow speed or even just slow go in low range you will much more likely to overheat your engine with electrical far rather than stock so long you are running engine anywhere above idle speed.

Notwithstanding detrimental/undesirable side effects.

 

[Monterorider]

Just bugs me why would someone think that primary cooling feature designed for street car weighting nearly half as much with smaller engine would best one built for that little gem of off-road as we consider it where engineers seemingly thought of every thing: mighty axles, strong frame, over-sized transmission, breather tubes, raised well protected air intake, etc, etc... Just something wrong here. Did they fall asleep working on cooling system or something? Won Paris-Dakar on magic carpet? Was it Ford/Volvo engineers preparing their 4 cars to tow 3 tonne trailers? It wouldn't bug me if we were talking about adding on, like slap additional electrical in front of radiator. There is always room for improvement. But replacing... For that matter it's a lot safer to just wire up that AC cooling fan to work on as needed basis vi switch in addition to stock cooling fan.

 

[eurosonic]

No problem. It's a very valid question.

To experience the overheating, try going up a steep grade in loose dirt (not even slipping) for ~5-10min while temps are +95f at <5-10mph @ 2-3Krpm then slow down as though there is 4x4 traffic ahead of you but keep moving up hill. You'll understand very quickly why this upgrade is very much desired.

At that speed/rpm the fan is turning too slowly and there is insufficient airflow to cool the coolant in the radiator plus your AT will be getting VERY HOT which will just add more heat to the radiator. I can almost guarantee you will overheat and quickly appreciate the benefits of an Electric Fan.

Good point offroader,
this summer I proved this to myself. After numerous of trips to the sierras, when I got to the trails, about 20 min into it I would start to overheat. Driving loaded uphill over rocks and loose, having low RPMs added tremendous amount of stress on the engine and transmission. It looks like the clutch fan was just not spinning fast enough to keep the heat down. I will be trying out the electric fan mod soon.

 

[Monterorider]

One question would what gear were your in? I'm not saying it's the case here but I've seen time an again people overheating/overtaxing there truck driving in 4H or even 2H over rough terrain as if trying to prove something. Keep you engine RPM around 2500-4000 this provides best highest torque, cooling, lubrication, efficiency. Never wheel in 4H if you have to climb or go slow. Use 4Llc and shift transmission into L in even if truck seem too pull in higher gear. There is no point so long you are not red-lining the engine. There is no harm in higher RPMs it's actually better.

If engine is hot, clutch must lock up. If not you need new one. They really need to be maintained/replaced on older rigs. Just like water pump for example at 120k

 

[Mudrunner]

Hey did they come with tranny cooler factory? I since we are talking about cooling things down, just curious.

 

[Monterorider]

yes

 

[Monterorider]

10 mph is pretty adequate 2500 RPM in 4L->L. Only real cure would be switching to 4.9 R&P especially if you want to run 35s.

 

[off-roader]

xcase is usually in 4L once you're going uphill. in 4H you just overheat faster.

MonteroRider, I have two words for you... Age / Wear. Everything wears with age.

Plus, as proud as we may be of Mitsu engineering I can guarantee the rigs are not designed for 100% duty off road. It wouldn't be feasable from a budgetary stand point. Closest thing we have 'available' for that are MilSpec rigs such as HumVee's.

As to the hows and why's, I'm not going to delve into the engineering minutia on this. If you want to, the guys on the 'wire can probably advise further as to the whys and hows.

For me the fact is, this 14 year old OE cooling system is NOT sufficient for heavy off road use without some aids. The AC fan is one option. Upgrading to the OE Volvo electric radiator fan is another. I'll be doing both.

FWIW, in near 110* in stop and go traffic up the Altamont Pass Grade, my engine does stay cool and the temp gauge doesn't budge above the typical temp. Take it off road and it will visit the red easily if you let it.

 

[Monterorider]

I have two words for you... Age / Wear. Everything wears with age.

Absolutely! Replace the clutch preemptively.

Plus, as proud as we may be of Mitsu engineering I can guarantee the rigs are not designed for 100% duty off road. It wouldn't be feasable from a budgetary stand point. Closest thing we have 'available' for that are MilSpec rigs such as HumVee's.

Absolutely. Volvo cars even less so.

I'll be doing both.

Perfect plan!

Ray how long have we been at this. I've got my first Montero before we moved to wire from what was it suv.offroad.com or something like that? I'd be coming on 13 years now.
I've never ever overheated my engine. Never really seen needle move up. Simple rule: keep RPM as high as possible as low are reasonable. When I wheel I always shift it to 4low and forget it, going slow/climb shift transmission to L and keep it high RPM. Again higher RPM are good: more air moves through radiator, more oil is pumped through gullies, more coolant flows, transmission locks up or at least sleeps less. Every single one of those factors keeps you moving keeps truck cool.

 

[off-roader]

I suspect the reason you've been ok is simply because OR temps are far cooler than CA temps. Rubicon in the Northern Sierra Nevada Mountains during summer is @ 90-100*F and it's VERY HARD going. It's even warmer in the Southern Sierras (Dusy Ersham, etc.). Then there's the vast complex of SCal trails which are always 90-120's & up during the wheeling season. During the rainy season, most trails are closed to minimize damage and added erosion from too much traffic.

 

[off-roader]

I've been into it since the mid 90's. My first 4x4 was a 90 v6 4 door Montero. I was active on the old vmag forums before I moved to 4x4wire. Always been Off-Roader on the forums since then.

 

[Monterorider]

I've wheeled in NV in 100+ I wheeled in Moab in summer and Co. In midwest for that matter before I moved to OR. 85 outside right now. It gets plenty toasty here in summer but that's not the point. You can overheat engine in middle of winter if you try hard enough. I'd rather do right thing. I just don't understand how car cooling fan can be enough for heavier more powerful, harder working truck.

 

[Monterorider]

yeah vmag that's the name.

 

[GrassCat]

Monterorider,

I added the electric fan because I wanted too and I report how I did it. Never did I say anything bad about the performance of the stock fan. The joy of owning a vehicle is you can do with it as you please, within reason of course.

All can search the web for answers you may have about what fan to run. I chose to run the electric for now, but who knows what lays over the next hill.

Here's a start http://flex-a-lite-blog.com/2010/02/27/which-is-better-–-an-electric-or-belt-driven-fan/

 

[Toasty]

Here's my experience, while rock crawling my truck would sometimes get warm especially in summer. I upgraded to a 3 row radiator, this helped but i still had to stop mid obstacle and rev at idle to cool it down at times. I then "upgraded" i guess to a direct drive fan (no clutch), same results so i'd say the clutch fan was doing it's job. When my 3 row popped i went back to a 2 row and a volvo fan, it is just awesome so far. I wish we could just get a high volume water pump or something though because i like the reliability of the mech fan not that i've had any issues.

Now my truck has 35's full armor 4.90's and 3.15's and would really only get warm during long rock crawls and long steep hills. So maybe once i upgrade my T-Case again i won't need the electric fan anymore but until then especially while i have a stock T-Case installed it's essential.