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1970-1995 Range Rover Classic
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Discussion Starter #1
I'm back with new overheating diagnosis help very much needed! Camper pics: instagram.com/roverlife

Recently put a few thousand difficult miles on the camper from San Diego, through the Rockies to the PNW. Before the trip I would have regular overheating problems when pushing the camper up long climbs, my first step was to regear the diffs... which I did just before leaving with 4.71's. I felt a load of relief from the engine and tranny, especially with my 35" tires (recent pic below). The trip started with 95 degree temps through Arizona and I had no overheating issues with the AC blasting. I thought I had found the fix with the re-geared diffs, but once we hit the climbs north of Pheonix I found the limit to the system again while I was pushing the car hard up the climbs. I backed off the gas on the hills and still had a bit of confidence until hitting some major passes in Colorado which required really babying the engine uphill and blasting the heat to keep from overheating. I was getting so much heat in the tranny that I melted my dog's favorite rubber chew toy (well deformed it a bit). I rolled into Boulder Colorado convinced that the tranny was the culprit for the overheating problem.

I ordered and installed a Derale Hyper-Cool dedicated tranny cooler with 500 CFM fan and removed the connection to the engine's radiator, which was a little risky without doing any kind of calcs to know if the dedicated cooler had a better heat removal capacity. It did, noticed it nearly right away while temps were brought down on the tranny noticeably (using an infrared heat gun). I was hoping for a major bump in engine cooling capacity from the tranny's heat from the radiator, and it felt like we were pushing some big hills north of Boulder into Jackson and not having overheating issues. Though it was also cold and we had the heat on.

We hit Jackson and the car began having overheating problems more consistently. Virtually any hill once the vehicle was fully hot after 20 minutes of driving would begin the overheating process... once we hit a flat or downhill, the temps would come right back down. So we began running the heat full blast with windows down, and could limp up most hills without issue, but some bigger climbs would still cause the needle to lift, sometimes to the 3/4 mark. Overall, it certainly seems like things are more sensitive with the system then they ever have been. The other thing is that I can do low speed driving (through backroads with hills) without any overheating issues. It's mostly highway speeds and long climbs.

I got to Portland and dropped the car by a reputable Land Rover shop. They said the radiator was only cooling 10 degrees inlet to outlet and said they felt the fan wasn't pushing as hard as it should and the first step was to replace the fan clutch. I swapped the clutch with no noticeable change... it was also Friday on a holiday weekend, so i felt like I didn't get much of the mechanics time before closing up shop, more like a best guess than a refined diagnosis. Overall they seemed convinced that the stock cooling system when properly working was more than enough for my camper set-up (which is pretty low weight ... the bigger strains are wind resistance and tire size at the start and stops).

The question is what to do next... my thoughts are that maybe the radiator is now 10% clogged versus a few thousand miles ago (radiator was re-cored about 2 years ago) and I simply don't have the capacity I used to have... and with the camper I'm really pushing the limits of the system to begin with. So I was thinking the next step would be to get a new radiator and splurge on something with bigger capacity.... all aluminum? Or should I re-core with a full copper, top of the line core? Or should I be looking elsewhere entirely?

I was considering to buy one of the all aluminum 4 core radiators off eBay, seeing as I really don't have time to wait for an Allisport. Or is a chinese knock-off a sketchy buy? Not cheap still, so I'm hoping that means quality.......... hoping......

Thanks in advance for the support and expertise. Apologies for the novel, but I wasn't sure how else to describe all I've done to work on this issue.

Here are some more recent shots: instagram.com/roverlife

IMG_3751.jpg
 

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1970-1995 Range Rover Classic
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Beautiful photos! Thank you for sharing.

Cooling issue: Are the bikes traveling upfront? If so, they may limit airflow?

My 95' has aux fans for additional cooling - they work; a noticeable difference in the mountains and on the highway ... not certain they were offered earlier?

Regardless, the fans are inexpensive (<$50 for two). However, installing would require a bit of fab/wiring on your part if not offered OEM.

Safe Travels.....
 

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That is not a camper conversion, it is an overloaded truck camper parked on a Classic. The load is way too much for a standard cooling system. At a minimum you really should have a custom upgraded radiator and secondary tranny cooler. Additional electric fans are for the A/C and do not come into play for general cooling under load. A manual switch can certainly rectumfy that, but will not address the standard sized cooling or added strain on the tranny. The additional fans also work if the A/c or Def are selected... slight added strain, but big difference in engine cooling.

If you visited PDX Briish then you were in the best hands possible for most any LR product. If you went to Shipmans, Doug is top notch in Classics, Disco and anything Series/Defender.
 

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1970-1995 Range Rover Classic
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I'm no cooling expert, however, I think your problem is heavy load + uphill (more engine loading) + low speeds (little airflow across radiator) = overheating.

If you had your radiator re-cored two years ago it should not be clogged if you have used 50:50 coolant to demineralised water, unless your engine cooling system was already clogged with buildup.

I definitely think electric fans with a shroud should help.

Here's a few links:

https://www.aulro.com/afvb/technical-chatter/232862-official-thermatic-electric-fan-conversion-thread.html
http://www.rangerovers.net/forum/8-range-rover-classic/30346-electric-fan-conversion-pics.html
http://www.jpurnell.com/rr/repairs/electric_fan_install.htm
https://www.aulro.com/afvb/technical-chatter/154865-electric-cooling-fan.html
https://www.johncraddockltd.co.uk/range-rover/range-rover-classic/accessories/cooling-fans/
https://www.johncraddockltd.co.uk/range-rover/range-rover-classic/accessories/cooling-fans/jc623-kenlowe-twin-fan-for-discovery-v8-and-range-rover-classic-v8-12-inch-suction.html

Check out / search that AULRO forum. I'm sure there are lots of heavily loaded V8 RRC's and Disco's running large tyres, towing in hot climates in Australia.

This sounds very frustrating for you but keep us posted how your getting on.
 

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I don't think that the weight is really a factor here. Yeah, your conversion is unconventional, but how different is it from towing a 8k trailer? The bikes on the nose are definitely blocking some airflow, but I doubt it's substantial, all things considered. The re-gearing has helped your situation without a doubt.


I think that you're problem is the radiator and thermostat.
- The re-cored radiator is great and all, but, it's not allowing for enough cooling. As nice as a larger, custom, radiator might sound I think that a new, stock, radiator would be sufficient.
- Do you have the 88C thermostat in place? If so, you might want to consider replacing it with a lower temperature one so that it opens sooner allowing for cooling to commence earlier.


Food for thought: the old radiator on my LWB would keep the temperature perfect until any form of incline, sitting in DC Traffic with the AC on, or towing. I replaced it with an OEM unit found on ebay for ~$160 and all those issues are now well in the past.

On my SWB (original radiator, 88C t-stat), I just towed U-Hauls 12x6 trailer (fully loaded), with the truck itself fully loaded, from DC to Rochester NY. The hills were brutally slow and the RPM's were well higher than I like, but no overheating issue at all. ( Start Elevation: 290ft, End Elevation: 483.4 ft, Max Elevation: 2320 ft)
 

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Discussion Starter #8
Great info packed in here from start to finish ... I overwhelmingly agree now that a larger capacity cooling system is the next step due to the already under-designed system on a stock RRC and the additional loads I'm putting on the vehicle with it's current set-up.

I'm still on board with the engineers that a lower temp thermostat won't improve overall cooling CAPACITY.

As for the electric fan vs. mechanical debate ... ALL the experts swear by keeping the mechanical fan ... and a fan that consumes 10 HP must be a **** powerful fan indeed. However, what I notice about the electric fans vs. mechanical is that they actually pull air much stronger in that it honestly seems like the mechanical fan makes a lot of noise but doesn't actually move a lot of air. My 500CFM tranny fan blows harder than the stock mechanical radiator fan. Are there any aftermarket mechanical fan blades? My engineering butt dyno is telling me that the fan blades themselves could have been designed to pull a lot more air for the same amount of HP.

Anyways, something to debate one day, I'd love to hear some opinions on why the mechanical fans seem to make a lot of effort to push a little bit of directional airflow. Either way, I trust the experts that the mechanical fans provide more cooling... just not sure how or why other than the sheer fact that a 10HP fan is a **** powerful unit that cannot be replaced by a much lower HP electric substitute.

Well, onto researching which larger capacity aluminum radiator to buy! Thanks again, I've messed with a lot of different vehicles over the years and the depth of knowledge on here is certainly impressive. Too bad my vehicle is too old for an ultra gauge or I'd really have some nice data to show engine temps vs all these mods on an overloaded RRC.
 

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You could use this temp test strips...
https://www.grainger.com/product/THERMAX-Non-Rev-Temp-Indicator-9UDG3?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/9UDG3_AS01?$smthumb$

As they show max temp reached. You can stick to engine sump, gearbox etc. They supply them in different ranges.

Cheers, Steve
 

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Discussion Starter #11
Good news from the field... I recently replaced the entire cooling system and am now running 40 degrees cooler and haven't budged the temp gauge, even after a recent run in Eastern Washington at 102F while blasting the A/C pulling hard uphill.

During the cooling system replacement I can't say I saw a smoking gun, but there certainly was sediment build-up in the system, in addition to a mix of green and orange coolant. As I suspected originally I still think the radiator was ~30% clogged, even though the system was only 3 years old. But having said that, even when the prior radiator was installed (an upgraded Nissen no less), the truck was still having overheating troubles on hot days pulling up long hills. This confirms the new system is pulling heat more efficiently than the old system even when brand new.

So here were the parts and fluids I settled on:

- Sadly (and happily) an eBay aluminum 4-row radiator. I would have gone with Allisport, but the time table for their delivery just simply didn't work. It was a risk, but when the radiator arrived I could have been happier... excellent looking construction (I was also an apprentice to one of the best TIG welders in the US) and it easily held 20 psi when tested at my local radiator shop. While 4 row radiators have been dogged by the experts due to turbulent flow across the breaks in the rows, I have to say I'm not sure I agree for this specific design. Compared to the 3 row Nissen, the breaks between tubes is incredibly small.. I could understand the claim on the Nissen, with large gaps between each row.
Over-all I would say the eBay 4-row out-performs the Nissen due to a slight larger capacity (a little thicker with the 4th row) in addition to the lack of gaps between the rows. I contacted the manufacturer, who also produces a 3-row aluminum radiator at a substantially lower price to see if the capacity and thickness is the same, just less rows (which would be preferred), but their 3-row is thinner and lower capacity.

- Meyle Water Pump .. The old pump's bearings seemed decent... not much play, but had a little bit of resistance and roughness initially to get the pump spinning. I replaced the pump because it had been at least 50,000 miles. The Meyle pumps were very reasonable on eBay, german made, and the gasket they provide is very similar in quality to the OEM gasket and not a cheap paper version.

- 74 degree thermostat .. I'll be running in very hot climates for the near future, and while this mod does nothing for cooling CAPACITY ... it surely kicks the system into gear before reaching more dangerous levels. Hoping it doesn't affect my gas mileage too much. I honestly wasn't a fan of this mod, but after talking with a number of dedicated mechanics who suggested it, not to mention all the ranting on here, I pulled the trigger.

- Purple Ice and Water ONLY. I'm fairly confident between the radiator and the fluid, this is where the cooling capacity increased dramatically. Due to not running in cold climates, I'm confident this was the right choice for maximum heat transfer.

Overall I'm running 40 degrees cooler than before, and definitely have a larger capacity cooling system than when the last radiator was installed. Pretty happy (and cool) camper... thank god I can run the AC again.
 

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1970-1995 Range Rover Classic
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?..you can now enjoy your trips looking out of the window, not at the temp guage!...
LOL! It's a Eover V8, one should always watch the temp gauge...



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