1991 200TDI to R2.8--couple remaining questions

[dkemm]

Why not dual stage fans? Like VW and Audi have done on their vehicles? Big fan and a smaller one. Small fan for “when in op temp” and a bigger one for when under load. Never had issues with any of my turbo charged vehicles getting hot in traffic or bumper to bumper traffic with the ac on.

E

I think the issue would be lack of space on a defender for multiple fans. Would need to squeeze (probably) 2x 16” e-fans to get close to the draw of a mech fan

 

[Ephry73]

I think the issue would be lack of space on a defender for multiple fans. Would need to squeeze (probably) 2x 16” e-fans to get close to the draw of a mech fan

Three pass red and the setup would definitely do it. I would have to see the setup. A lot of folks switch to the Ford shroud and fans for ease of use and built in controlled.

 

[MountainD]

I wonder/ed everything! Including inconsistencies with water pumps, plumbing, leak downs, and thermostats! I’m not sure what! But give me just 1 person here in CO (or altitude) in an R2.8 defender—just 1— and I’ll ride shotgun over a pass at normal speed and if no issue, then good luck getting my nose out of that engine bay! So far, of the people I know with R2.8’s living at altitude, 0 with electric run cool. so hey, who out there has run in steeps on electric fans successfully, out there in an actual R2.8 first hand? Let’s chat! I’m not alone, here…. Cummins R2.8 swap Facebook page gas a bunch in all sorts of vehicles With same issue. Common mistake? I’d LOVE to know what! Maybe it is something else, an anomaly of components or plumbing routing. See anything strange?

Honestly, open to suggestions and advice if you see something airy. If this thread has proved anything, its that I learn from my mistakes and I’m not too proud to admit it! As for Doug’s posts, sure, I’ve read them, too. You’d think it’d be easy. And yet, here I (and others) am.

 

[dkemm]

I will add… when I got my over heat error code, things began to cool just fine. This led me to investigate - which led to the EGR cooler. The engine goes into a limp mode that blocks off the egr cooler. So, sustained loads on hot day at elevation (thin air) lead to the e-fans not being able to keep up with heat soak and egr cooling. Keep in mind that my issue was at 75mph so I had air flowing through the radiator (v1.0) w/ my v1.0 FMIC that was about the same size as the radiator.
I reached out to a local R2.8 person for help. He has 2x R2.8 - one in a Land Cruiser 70series, the other in an S10 he is building for Diesel Land Speed record… oh, and he worked for Cummins on the R2.8 Project. While he is using e-fans, his Land Cruiser isn’t towing and has lots of grill real estate to work with. His S10 is running a small radiator as his run are short, using air-water aftercooler w/ ice water. This is also pre EGR engine w/ custom ECM.
All that said, EGR / cooler removal will affect the tune negatively, so that’s a no-go… leaving mechanical fan as the easiest/ (least) expensive option that’s effective. I even looked into hood vents to exhaust hot air in the engine compartment prior to mech-fan.
I believe that the mech fan also facilitated removal of hot air that builds up around the turbo / exhaust - leading to a cooler engine compartment.
If you are space limited and must go e-fan, I get it! Simply be advised that you may encounter cooling issues— especially if you are at elevation above 5000’, towing or sustained 2500+ rpm drives under load.

 

[Francois1]

I have not been able to test mine in altitude. So far maybe 3000Ft in 60-70 temps, but but the outside temperatures in AK are starting to go below zero so I will have to wait until next year to see it perform at higher altitudes/temps.
My cooling system is not plumbed the same way. I did not tap into the bottom rad hose like the manual says, and I did not connect any lines to the bleed screw behind the alternator. I only have my coolant tank connected to the top of the rad and the thermostat housing. I am still running the electric fan but I have the mechanical kit as well in case I start having problems (but I am pretty sure it won't clear my PS gearbox). I do not have an A/C compressor.
Have you tried to run it with the webasto isolated from the system? I wonder if Cummins has any test data for high altitude performance and how they plumbed their black test vehicle. When I watched their videos, I remember it was pretty evident that they had deviated from their own installation guidelines.

 

[MountainD]

I have not bypassed the webasto, but I certainly can and, frankly, if the mech fan doesn't work perfectly, I will be doing just that. However, those familiar with the webasto's know they flow pretty freely through there and frankly many folks don't run a heater core at all, so I am not sure how it could negatively affect things other than air in the system, but I did a forcedown of fluid through the heater core, through the webasto, so I know they have been purged. But I can certainly check it out further and appreciate the advice.

I would love to know if the folks over heating have a common plumbing configuration... But comparing to flat landers not running at 90F+ at altitude doesn't do much good as I have not had many issues on flats in cooler weather (even at altitude) at all unless I am towing at 80mph. It is just when ambient heats up and/or I hit the hills which last miles out here...

I've seen several folks NOT go from the engine bleed screw to the vent line, so maybe I will bypass that and see if there is a difference. Worth checking on at least. I don't WANT to go mechanical--It would be way easier for me to not make a custom shroud

 

[erover82]

If you take a look at the cooling strategy of a modern truck pushing more weight and cooling down many more Watts than an R2.8 you'll see generally use dual fans, the largest that will fit, and they're thick paddle-blade type for lower noise and to overcome the static pressure of a large cooling stack. A Defender does have a relatively narrow area for cooling, but an R2.8 doesn't put out many Watts either. Just interesting to think about.

If we take a step back though, your fan setup should be irrelevant over 30 MPH. There is a huge surface area with a ton of pressure against it at your "80MPH". I'm wondering if that flow is not making it through the grille and stack efficiently. Looking back at your photos I see a large winch and gaps throughout the cooling stack where that airflow may be diverting instead of preferring to flow through the relatively restricted radiator, shroud, and fan. Along this line of reasoning, perhaps the reason you're seeing success with the mechanical fan is actually because the restriction of the shroud and fan has been removed. If you removed shroud and fans altogether, would you still have success at 80MPH? If you retained the e-fan setup and closed all gaps through your stack, would that force air to flow properly though the final stage in your stack (radiator), and also lead to success? Could the curvature of the top of the winch be causing an aerodynamic anomaly where air flows over the bonnet instead of through the grille? I don't think I saw a photo of your grille setup.

 

[MountainD]

I have another thought on the effectiveness on why some folks have success on the fan and that is to move the heat OUT of the engine by and create a flow that will overcome static pressure. The fan/radiator on a Corvette 6.2L LS engine is smaller than a defender's and yet I know plenty of folks that have had issues on a defender and not on a Corvette. It is base up design on airflow and total static pressure. But interesting conversation. I was running a single fan, no shroud at all ( 16” spal 30102049) and had issue with heat at speed up here. That is with the fan directly pulling through the cooling stack. I took it off, put on a mech fan 9" offset from the cooling stack, and I am just fine. So yeah, I am sure you could get there eventually with E-fans. Give me a 4000-5000CFM at 15mmH2O static pressure, and I bet we would be there. If it isn't too expensive, I may just do that! But alas... I sure haven't found that. I can tell you that 3000CFM doesn't cut it either. But it WOULD eventually get there---I am not arguing that it couldn't. Just that one's that fit that I have found don't cut it.

 

[Nick&Nora]

The first post of Uncle Doug‘s R2.8 threads on the other forum, “Cummins R2.8 into a Defender” talks about the cooling package/heat exchange working so well Cummins had turn the fan on remotely. My understanding is that his cooling package is the same thing Allisport sells these days.

Would you attribute that solely to altitude and mountains? Or do you think there is something else ?
Wondering if Cummins changed something on their end over the few years, because he also talks about that truck going deep into Colorado mountains without issue.

(Also feel free to ignore this if my understanding of that cooling package is wrong)

I have one of Doug's trucks. He installed the Cummins et al into my 1989 110 in 2020.

I've had uncomfortably high temperatures twice. Once was climbing from about 4500 to 6700 feet on 54 in New Mexico in late September. Ambient temps were over 100, and, embarrassingly I didn't realize I was pushing it as hard as I was or gaining that kind of altitude. AC was running; I wasn't towing anything, but the truck was pretty loaded.

The second time was driving across central Massachusetts in July, when it was 100ish and humid. Stop and go traffic on the interstate. Turning off the AC kept temperatures below 200. Long-suffering wife not amused by turning off the AC, it has to be said.

Under normal circumstances, when the Murphy gauge reads 196, the fan kicks in and temperatures drop fairly rapidly.

-Matthew

 

[MountainD]

I will say Doug/Kraig‘s cooling package is very similar to Allisport. Matter of fact the Fan (Spal) I have was originally for Kraig’s and it identically works on Allisport. I couldn’t use that set up and had to send it back (fan bought separately) but I can say first hand they seem similar on the surface dimensionally. I know from NickandNora and Norton that they work for some in their conditions and I respect those guys for designing it! Pull a trailer and/or go over steep passes, that is my need, and I don’t believe it’s suitable. This is based on first hand use.

Is it possible I have an airlock? Stupid to say it isn’t possible. And if was just me with this issue, I’d say probable— or at least some component I have in the engine is faulty. And I still contend it is possible. But just less likely. And if I didn’t tow, I’m sure I could get cooling to a place I could live with. But I do. And I have the wife & A/C condition to contend with. And I’m tired of staring at my gauges all the time worrying…

And folks, don’t get me wrong! I’m not anti-electric nor saying what you have used/planning to use isn’t suitable! If it works for you, great. I’m describing a particular use intent and sharing my observations (so far). I’m not even sure the mech with shroud will work yet! We will see soon enough, not in a rush as I don’t overheat in winter…so there is time

@erover82 here is the front (with muffler—again, no issue in winter!). I do have a winch, but minimal blockage and only HD drag arm, no skid plate on front underneath.

 

[Nick&Nora]

And I have the wife & A/C condition to contend with. And I’m tired of staring at my gauges all the time worrying…

And folks, don’t get me wrong! I’m not anti-electric nor saying what you have used/planning to use isn’t suitable! If it works for you, great.

No worries; I'm following with interest, as I hate the worry as well, even without towing or living at altitude. Ultimate my truck will live in Arizona, and I will definitely want to feel good about running AC and going where i want to go.

 

[KW1985def110]

I’m sure you don’t want to keep throwing money at the issue, but I wonder if converting to a different style charge air cooler would free up air flow for the radiator ?

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[MountainD]

I’m sure you don’t want to keep throwing money at the issue, but I wonder if converting to a different style charge air cooler would free up air flow for the radiator ?

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Intercooler For Cummins R2.8 Aftercooler for tight spaces on the diesel engine swap for the Defender, scout , or Bronco

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Never considered one due to heat soak. TBH, I have never been a fan of them for this reason from past builds and track. I know someone right now that is running the R2.8 in a Delica (how cool is that!) that is going to go back from the AWIC to a FMIC due to heat soak (on the Cummins R2.8 FB forum). But that is their story to tell---if you are on that forum you will know who I mean. Friggin cool build.

There is always a trade off!

 

[Ephry73]

That’s weird. My previous statements were only made because of any the motor shouldn’t overheat that much. The coolant mix is done correct? Had to ask.

E

 

[dkemm]

That’s weird. My previous statements were only made because of any the motor shouldn’t overheat that much. The coolant mix is done correct? Had to ask.

E

yep. as Chris noted...this is a common occurrence with the R2.8 (not just Defender installs).
If i recall correctly - engine throws an error code at 225degrees (which I consider on the low side compared to my car getting to 280's w/o a problem). Also noted previously...this doesn't happen on flat land or low elevation or without load on the engine. The issues to crop up during summer time heat (ambient near 100F), sustained uphill (load on the engine), or towing (again load on the engine) and all that at 5000ft+ elevation.

I believe that the purpose of posting here is to share the learned knowledge and hopefully save others from additional spend / time for cooling package installs. If your install is space limited and requires an eFan - I get it - again hopefully saving others time & money by making informed decisions.
From my own experience - I would say its the heat soak and the EGR cooler adding additional heat to the system.
My cooling package efforts:
v1.0 was a single pass radiator (372 sq in surface) w/ 1600cfm 16" SPAL. (this was behind a FMIC also 272 sq in)
v1.5 was upgrade to a 2000CFM SPAL (front area fully sealed so all air was directed through radiator)
v1.6 changing to a 50% smaller FMIC so that the radiator had clean air passing through it
v2.0 was upgrade to dual pass radiator that was 522 sq in (40% bigger core) - this dropped temps, but still higher than I want to see. (2000cfm SPAL/original shroud)(original shroud left some un-shrouded area to facilitate highway speed free flow) smaller FMIC also ducted to "hot side" of dual pass radiator, leaving "cool side" clear
v2.5 was change to Mechanical Fan - When I first installed mFan - eFan and shroud were still in place - temps dropped to acceptable level
v2.6 - removed eFAN & shroud, running mFAN un-shrouded for testing -- while I build a new shroud - no problems with cooling
v2.7 - *coming soon* - in the process of building the custom fiberglass shroud to facilitate proper flow through radiator.

Why the mechanical fan makes such a tremendous improvement over the E-fan can be many factors - I also struggled to understand how an eFan was not up to par with mFan.
1. static pressure in the engine compartment - hood vents could possibly fix this (I didnt go this route)
2. Fan blades - w/o getting into blade pitch, rpm, etc...mFan blades have more surface area
2. M-Fan does push more air (even prior to full clutch lockup) than the eFan (this could also be clearing out hot air from engine compartment
3. Currently with 60-70 degree ambient temps, murphy gauge stays in low 170's, with only partial flow from thermostat to radiator. Where I would hit 212 consistently w/ eFan, now only gets to 189MAX. Like Chris...I will likely be running a radiator muff into the winter so that proper warm up happens

If anyone is interested, I do have some used FMIC's, radiator, silicon hoses and fittings...

 

[erover82]

It would be an interesting test to remove the mechanical fan, stow it in the vehicle, and go for a test run that is known to push the thermal limits. At speed, the fan should be irrelevant so the outcome should indicate the root cause.

Overheats - Probably a heat soak / engine bay cooling issue
Runs cool - Probably a cooling stack airflow issue

 

[erover82]

I’m sure you don’t want to keep throwing money at the issue, but I wonder if converting to a different style charge air cooler would free up air flow for the radiator ?

Intercooler For Cummins R2.8 diesel engine swap adapter kits

Intercooler For Cummins R2.8 Aftercooler for tight spaces on the diesel engine swap for the Defender, scout , or Bronco

quickdrawbrand.com

Most discussion I've seen of these air/water heat exchangers is in the context of motor racing where the water is chilled with ice or runs through a secondary cooling loop. If this is intended to "cool" charge air with hot coolant, I wonder how effective it can be even given water's high thermal mass.

 

[dkemm]

It would be an interesting test to remove the mechanical fan, stow it in the vehicle, and go for a test run that is known to push the thermal limits. At speed, the fan should be irrelevant so the outcome should indicate the root cause.

Overheats - Probably a heat soak / engine bay cooling issue
Runs cool - Probably a cooling stack airflow issue

great idea...
I have to remove the fan to install the shroud...so I can go for a drive first.
The other tough comparison part is simply the lower ambient temps of winter...

 

[KW1985def110]

Most discussion I've seen of these air/water heat exchangers is in the context of motor racing where the water is chilled with ice or runs through a secondary cooling loop. If this is intended to "cool" charge air with hot coolant, I wonder how effective it can be even given water's high thermal mass.

That’s where I’ve seen them used as well. Never used one personally. Also never understood how they work in non-racing applications as you mentioned. Was throwing it out there as an “out of the box” option to free up air flow in front of the radiator.

 

[MountainD]

I only know one person so far, happens to be in CO, that is running one--you will see him as Rio on the R2.8 forum. He is about to remove his due to heat soak and throwing the high ambient air temp code when running to heat soak. He is also running nearly a 30" wide radiator, so massive compared to ours. His is an high air intake temp code---so he is going back to FMIC.

My experience isn't with rovers or with R2.8's but I have never been a fan. It is a good option for some, but the theory of it isn't good in my opinion, at least for my use.