5th Gen Mods, Accessories, Install, Off-Road, Overland, Performance, Reviews

CSF High-Performance Radiator Install + Review – 5th Gen 4Runner

Updated 12/26/20 / Read Time: 12 mins

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner


Earlier this year, CSF High-Performance launched its new all-aluminum, heavy-duty radiator for the 5th Gen 4Runner to address the issue many of us have had with overheating on the trails.

CSF has made a name for itself in the motorsport’s world by manufacturing high-quality import and popular domestic radiators, intercoolers, and oil coolers. However, it surprises some people to find out that the company is rooted in off-road radiator manufacturing.

They started tackling the 3rd Gen Land Cruisers and FJ40s well before the 5th Gen 4Runner was a thing… or the 4th… or the 3rd… you get the point. So, it was only a matter of time before CSF decided to address the 5th Gen 4Runner’s much-needed radiator upgrade.

Heat Soak Technology For Greater Efficiency & Higher Engine Power On the Trails

CSF’s all-aluminum radiator addresses a major issue that we hope very few of you have had to experience; “heat soak”.

Generally speaking, you don’t see a lot of 4Runners out there racing Baja-style; they’re crawling up trails and mountains or through deserts at slow speeds while still producing high engine power. This leads to the engine phenomenon known as “heat soak”. Once the vehicle is shut off, the radiator stops doing its job of cooling the engine and in some cases, can lead to engine fires. By upgrading to their all-aluminum radiator, this could help overheating issues due to its increased size, which in turn, increases the efficiency of the radiator core and radiates heat away from the engine faster. More to come on the radiator size…

So, what exactly does a car’s radiator do?

A car’s engine needs to run at the right temperature in order to perform at optimal levels. When a car’s engine overheats, that’s when things start to go south. The purpose of the radiator is to prevent your engine from overheating by pumping coolant throughout the engine

What is radiator coolant?

Radiator coolant is an antifreeze fluid that is designed to absorb heat and carry it away from your engine. The car’s thermostat helps to ensure things don’t overheat.

What does the thermostat do?

A car’s thermostat sits between the engine and the radiator. The thermostat prevents the engine from getting too hot by opening and closing its valve allowing coolant to flow (or not flow) to the engine. Wax sits within the thermostat that connects to a rod. When the wax starts to melt (meaning things are heating up), the valve opens releasing coolant from the engine to the radiator. The coolant then flows from the engine to the radiator, where the fluid passes through rows and rows of metal fins cooling down the fluid by leveraging the air outside of the car (the heat is actually “radiating” away from the engine).

Why should you consider replacing your radiator?

As with any large-scale manufacturing operation, there’s (hopefully) a happy medium between “good enough for the masses” and “won’t break the profit margin”. When it comes to your 5th Gen’s radiator, that logic was put into effect. The radiator is a combination of plastic and aluminum, which likely is “good for the masses”. While we’re consumed with the 4Runner world and think everyone who has a 4Runner has it dialed in, the truth is, most owners just use it as their daily driver. The plastic/aluminum combo, again, is “good enough for the masses”. However, if you off-road, overland, or just work your engine in some high-heat situations, you run the risk of gaskets and seals melting or busting, causing potential engine damage.

Additionally, plastic tanks crack over time causing leaks that lead to overheating, which obviously leads to engine failure. Plastic is good for some applications, and for others, it’s just not sustainable. But again, it’s cheap and cheaper than manufacturing all-aluminum radiators at scale.

So, if you’re in need to replace your radiator or just want to avoid an issue like this altogether, pay the extra $100 or so and upgrade from OEM to the CSF all-aluminum heavy-duty radiator.

Product & Price

CSF’s all-aluminum heavy-duty radiator is larger in size but still fits perfectly where the OEM radiator sits.

Your OEM radiator has a 1-row 22mm core, where the CSF radiator has a 2-row 42mm core. In essence, this radiator packs almost double the cooling power. Plus, it’s made with CSF’s unique B-tube technology:

“B-Tube technology – Unlike a regular oval shape “O” type radiator tube, CSF uses a specially engineered tube in a shape of a “B”. These “B-tubes” are carefully formed and then brazed over the seam to seal. CSF is able to use thinner and lighter aluminum material (better cooling efficiency) because this design is actually stronger than normal “O” shape tubes that are welded.”  – CSFRace.com

The radiator is TIG welded all around, which prevents potential leakage in comparison to the plastic OEM radiators that utilize rubber gaskets and a crimp design.

Again, it mounts directly in place of the OEM radiator. As you’ll see in the installation steps below, once all the steps are taken to properly remove the OEM radiator, this one just slides into place and bolts back up the same way. All the mounting points are identical, including the radiator cover that sits along the top of the engine bay.

CSF vs. OEM Radiator

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner(Left: OEM, Right: CSF)

Genuine Toyota OEM parts can be pricey, but in a lot of cases (like lower control arms), you want to stick with OEM unless you’re upgrading to something with better capacity or of better quality. We’ve seen the prices range for a 2010 – 2020 4Runner radiator from $325 – $450.

The CSF radiator comes in around $100 more than OEM, but for that extra few bucks, you’re buying something with double the capacity, which to us is the price for peace of mind! Plus, it comes with a 2-year warranty and it does look shiny in the engine bay!

Find it online: 

  • CSF Radiator (All-Aluminum High-Performance) | 5th Gen 4Runner: Check Price

Where this thing really stands out is the fact that CSF’s radiator increases the capacity of the transmission oil cooler. This means that for those who haul heavy loads (i.e., 4Runner full with overlanding gear, rooftop tent, steel front and rear bumpers, etc.) or those who tow (i.e., general towing or towing an overlanding trailer behind their rig), this radiator will keep your transmission much cooler than the OEM radiator.


CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Right from the gate, you can tell you just bought a quality product. The radiator fins needed to be protected at all costs, so CSF takes their radiator packaging seriously. While it’s not like unboxing a new iPhone, it’s pretty darn close…

The radiator comes packaged with a pliable foam on both the top and bottom, taking into consideration the grooves, valves, etc. with necessary cutouts.

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

As the center of the box can still get punctured and damage the fins, CSF wraps the radiator in a dense blue plastic which is to aid in kicks or punctures to the box.

Then, once you remove it from the plastic housing, the shine and precision might just take your breath away!

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Alright, this is where the fun begins.

I couldn’t find much in terms of 5th Gen 4Runner installation steps, but, that’s what Trail4Runner.com is all about! Follow the steps below, take proper precautions, and don’t rush a job like this. Expect to spend between 2 – 3 hours from start to finish, which includes about 20 minutes of monitoring at the end of the install.

Tools Required: 

  • 10mm Socket Wrench + Extension
  • 12mm Socket Wrench + Extension
  • Plastic Clip Remover
  • Drip Pan (+ Way of Disposing of Any Fluid Waste)
  • Funnel (or Radiator Funnel Burping Kit)
  • Flathead Screwdriver
  • (x2) Needle Nose Vice Grips (or x2 Line Clamps)
  • Hose Clamp Pliers (or Channel Lock)

Materials You’ll Need:

Step 1. Remove Skid Plate

Removing the skid plate is required as it will provide easier access to the underside of the radiator and allow you to open the petcock.

Step 2. Remove Radiator Cover

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Next, you’ll need to remove the radiator cover from the top of the engine bay (you won’t be able to access or remove the radiator without it being removed).

Note: We learned a while back that these specific plastic clips on the cover can be a pain. So, we bought extras.

However, you should be able to remove them with your plastic clip remover tool. Start by slowly lifting the center tab (not completely), then removing the outer tab. Remove all thirteen (13) clips and set aside. If you broke any in the process, they’re not expensive and good to have on hand.

Step 3. Drain Engine Coolant

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

With the skid plate now removed, locate the petcock on the bottom of your OEM radiator. It should look like a small plastic wingnut. Line up your catch/drip pan directly below the petcock and slowly open the valve counterclockwise. You’ll see a pink/red liquid emerge from the valve; this is the engine coolant and it should be completely drained before removing the radiator.

Pro tip: To speed up the process, locate the radiator cap on the top of the radiator and remove it. You’ll see the coolant flow out faster.

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Step 4. Disconnect Clamps from Upper & Lower Radiator Hoses

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Since we were upgrading the radiator, we decided to swap out the hoses for newer ones. Check your hoses before doing this install; if you see cracks in the rubber, it might be time to change yours out as well. For most, this might be an optional step.

If your hoses look good, use your channel locks (or hose clamp pliers) and back off the upper hose clamp from the radiator. If you’re not replacing the hose, there’s no need to remove it from the engine; just back it off and out of the way for the time being.

You’ll also want to remove the clamp on the lower radiator hose.

 Upper Portion of Lower Radiator Hose

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Note: The picture above shows the upper portion of the lower radiator hose. If you’re not replacing the hoses, you don’t need to back the clamp off from this section.

Follow the hose to the bottom of the radiator and back off the clamp on the lower portion only.

Step 4. Disconnect Transmission Cooler Lines and Clamp

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Locate the two lower transmission cooler lines.

In order to avoid losing a ton of transmission fluids, use a set of line clamps if you have them to pinch the lines before removing the hose clamps. We didn’t have a set on hand, so we used needle nose vise grips to loosen it up enough so we didn’t pinch the rubber but tight enough to hold the transmission fluid back.

Pinch the lines and back off the hose clamps.

Step 5. Disconnect Overflow Hose

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

The overflow hose is located directly behind the radiator cap. Simply remove the hose from the radiator and push it aside.

In a later step, you’ll need to remove the overflow reservoir completely from the radiator.

Step 6. Remove Fan Shroud Bolts

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Using your 10mm socket wrench, remove the four (x4) bolts holding the fan shroud to the radiator.

In this process, you’ll also need to remove the overflow tank as it’s connected to the fan shroud. The overflow tank has three (x3) 10mm bolts as well. When removing the overflow tank, keep it upright when setting aside to avoid any radiator coolant spills.

Step 7. Disconnect Transmission Mounts

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

The transmission lines are mounted at two (x2) locations on the backside of the fan shroud.

On the lower side (underneath your 4Runner), one transmission line has a clip welded to it that is connected using a 10mm bolt. Remove that, then move to the top side of the radiator through the engine bay. The two radiator lines are clipped in using a mounting clamp. Use your flathead screwdriver to free that clip from the shroud.

Step 8. Remove Fan Shroud

With the transmission lines removed from the fan shroud and the mounting bolts disconnected, you should now be able to remove the fan shroud.

Step 9. Unbolt & Remove Radiator

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

It’s important to note that during this step, you may need to remove your front bumper. We’re running the C4 low-pro front bumper, so we had access to the lower two (x2) of the four (x4) bolts holding the radiator in place. If you don’t have an aftermarket front bumper, you’ll likely need to remove it altogether to access these lower two bolts.

Remove all four bolts using your 12mm socket wrench and any necessary extensions or elbows you might need. Be patient, as those lower two radiator bolts are a pain to locate and remove, unless you remove your front bumper – which is also pretty easy.  For removing the front bumper, you can read this post.

Once unbolted, the radiator should slide out relatively easily.

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Step 10. Clean Your AC Condensor

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Now that the radiator is removed, it’s a good idea to use some compressed air or a shop vacuum with a bristle head, to clean the air conditioning condenser. Once the radiator is back in place, you won’t get this chance again. So, use the opportunity wisely!

We also used some degreaser to clean the general area while everything was removed and gave the fan shroud a good cleaning.

Step 11. Prep Radiator with Included Foam Strip

CSF includes a strip of adhesive foam to adhere to the bottom of the radiator. Look at your old radiator for guidance on where they should go. In essence, you’ll need to cut the strip in half and stick to the lower left and right corners of the radiator.

Step 12. Reverse Everything You Just Did!

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

Now that you have the new radiator ready for installation, simply perform steps 1 through 9 above in reverse order.

  • Ensure all of your hoses are reconnected properly and the clamps are in place.
  • Use grease, or spit, or warm water to loosen the hose end to force the hoses onto the new radiator.
  • Ensure the fan shroud is sitting in the “H-brackets” on the bottom of the radiator.
  • Make sure not to overtighten the bolts on the fan shroud, since it’s plastic and overtightening could crack the housing.
  • Leave the radiator cover off for the time being as this will be the final step.

Side Note: We had some extra foam stripping on hand, so we ran a strip along the top between the radiator and the frame. That’s not a necessary step, but the OEM radiator had it on there, so we put the extra piece back in. In talking with CSF, they shared with us that they plan to include that strip for the top of the radiator with future production runs.

Step 13. Fill’er Up

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

With the radiator in place, and everything completely bolted in, it’s time to pour in the radiator coolant. The coolant is already pre-mixed with water, so there’s no need to cut it any further.

Start by tossing a sheet or two of cardboard underneath your 4Runner to check for leaks. Using your funnel (or the radiator funnel, if you have one), begin to slowly pour in the coolant. Fill it to the very top leaving about half an inch from the top of the radiator filler neck.

Don’t forget to check for leaks on your cardboard.

Before starting the 4Runner, leave the radiator cap off. The lines will undoubtedly have air in them, so you’ll want to “burb” them out. Start your 4Runner and let the engine run for a few minutes. Put the emergency brake on and give the engine a few revs. We turned our air conditioning on full-blast so that we could start to heat the engine and open the thermostat to let the coolant flow back and forth from the engine to the radiator. You’ll start to see a few bubbles emerge and the radiator will begin to heat up.

After 20-minutes or so and a few bubbles, you should be good to put the radiator cap on. Clean the area, check to see if you have enough coolant in the overflow (add some if needed), and shut the car off.

Step 14. Reinstall Radiator Cover

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

This is the final step in the installation.

Now that everything is done and you’ve checked everything to ensure it’s working properly, reinstall the radiator cover using the clips. Clean the area and pat yourself on the back; you’ve successfully swapped out the radiator!

Final Review

CSF High-Performance Radiator Step-By-Step Install + Review For the 5th Gen 4Runner

We’ve only had the radiator in for a day, so we’ll follow up in a few weeks with a “Trail Impressions” review.

Steamy hot summer days in Philadelphia are right around the corner, and all the states for that matter. We’re looking forward to hitting the trails to give the CSF a test. In that review, we’ll include before and after temperate readings from our ODBII app (we took some readings before this installation while on a trail).

In regards to the product itself, the sheer weight, appearance, structure and design tells you it’s a solid product.

CSF has been in the cooling industry since the 1940s and they’ve perfected their product time and time again. Lots of aftermarket parts don’t always bolt up as easily as OEM, but this radiator did. We’d never swapped a radiator before, so admittedly, we were a bit nervous. But once it was done, we were kind of surprised how easy it was.

Kudos to CSF for a solid, solid, solid, product. We’re looking forward to putting it to the test on the trails in a few weeks!

Comments or Questions? Leave them below!

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January 11, 2021 8:12 pm

Thanks for the writeup!! Super helpful. Going to bolt on a C4 Fab Lo Pro and thought I would upgrade the radiator at the same time. Very interested in a quick update on the performance and any issues following the install.

Kipp Johnson
Kipp Johnson
July 26, 2020 4:40 pm

Ryan this was awesome and thanks so much. I just did this install and it went really well. Only one hang up I had maybe to discuss in case others get stuck here also. After removing the fan shroud bolts and the overflow tank, and releasing the two clips, I had the tank off and the shroud “floating” freely. However I could not for the life of me figure out how to remove the shroud without taking the radiator out. Maybe I misunderstood but it seemed like in the write up I should have been able to take it out… Read more »

July 2, 2020 8:19 pm

Thanks for this write up, I ordered one after I read this for my 2016 Runner as a I do a lot of towing, twice a month with a 18’ travel trailer. Install was pretty straight forward, especially if you’ve done a radiator before. I have a stock bumper and you 100% have to remove it to get those two lower bolts. Not hard though, just takes time. Driving around town temp gauge looks the same. Wanted to invest in my ride as it does a lot for the family. Doing my first trip down CA coast in a couple… Read more »

Joe K.
Joe K.
June 19, 2020 5:30 pm

Is there a similar product for the UZJ120/GX470?

My searches didn’t point me to equivalent, but the replacement steps look so familiar.

Thanks for the write up.

Michael J Was
Michael J Was
June 19, 2020 7:59 am

Just wondering…do you see a difference in the temp gauge after the radiator install? should be running cooler?

June 19, 2020 5:20 am

Ryan, great write up and appreciate the detailed remove/replace/install. This site is great for knowledge and information. If you are still looking for a means of monitoring the transmissions temperature I might recommend the Scangauge device that plugs directly into your OBD2. I have it on my 5th Gen TRD Pro 4Runner and keep an eye on the temperatures. I checked the owners manual to see what normal and high operating temperatures were but nothing was listed. I spoke with the techs at Toyota and they informed me under 200 is ideal and anything 200-230 is high. If approaching those… Read more »

Cal Mitchell
Cal Mitchell
June 18, 2020 2:53 pm

This engineering statement concerns me comparing Toyota OEM tube thickness to CSF tube thickness. Thinner tubes engineering wise has better thermal transfer but also and this is critical rot out a lot quicker. So tell me what CSF does in this specification. What are OEM and CSF wall thickness specs???? and life,,, CSF life expediency I drive in Ontario Canada salt in the winter. Is CSF worth the money and time investment???? “B-Tube technology – Unlike a regular oval shape “O” type radiator tube, CSF uses a specially engineered tube in a shape of a “B”. These “B-tubes” are carefully… Read more »

Minh Nguyen
Minh Nguyen
June 4, 2020 11:28 am

How was the difference in temp via the OBDII Before & after install?
Any noticeable difference? Especially curious about the Radiator’s transmission Cooling ability.

Eddie B
Eddie B
June 4, 2020 11:12 am

Excellent writeup, good to see more replacement parts for the 4Runners of superior quality and decently priced compared to OEM. I like your comment (As with any large-scale manufacturing operation, there’s (hopefully) a happy medium between “good enough for the masses” and “won’t break the profit margin”) in my opinion this is key when it comes to decide on OEM quality vs aftermarket (and reputable) parts.

Chris - @Deadeye.4r
Chris - @Deadeye.4r
June 4, 2020 6:47 am

Great article and install on something I had never even considered as being a potential problem! I live in Texas and plan to do mostly rock crawling so now I’m considering this installation. I’ll have to keep an eye on my temps before and after to see if I’m going to be having any issues.   A few questions:   Do you know what temperatures are acceptable/problematic for both the engine and transmission? I assume the owner’s manual would say something, but it doesn’t list everything. Knowing the boundaries for these would be very helpful in determining if the upgrade… Read more »

June 4, 2020 8:45 am

Chris,   Regarding your Question #3: The engine coolant and the transmission fluid are two completely different items and do not mix. The radiator is a dual purpose radiator that circulates the engine coolant and transmission fluid in two separate areas of the radiator. Therefore, the engine coolant and the transmission fluid are always segregated from each other and never mix, unless the radiator has failed, in which case the radiator must be replaced and both the coolant and transmission fluids must be flushed completely and replaced. Mixing of engine coolant and transmission fluid is detrimental to the cooling system… Read more »

Chris - @Deadeye
Chris - @Deadeye
June 4, 2020 12:08 pm
Reply to  Paul

Ahh, I see now. The transmission fluid itself is cycled through the radiator. Yeah, mixing these would be bad. lol.   After looking through a few videos, it appears checking the levels of the transmission fluid isn’t too complicated and would be a good step. Also, you could attempt to drain or flush out any ATF WS fluid from the previous OEM radiator and measure that amount, then just add that same amount back into the system. However, there actually might be more fluid needed with the larger CSF radiator (more potential volume). Sounds like checking might be the safest… Read more »

Last edited 7 months ago by Chris - @Deadeye.4r
June 4, 2020 1:01 pm


June 4, 2020 6:06 am

Did you need to add transmission fluid? If so, please discuss.

June 4, 2020 6:32 am
Reply to  Ryan Gibbons

I understood your description of pinching the transmission lines, but I assumed some transmission fluid would remain in the old radiator after removal.

June 4, 2020 6:53 am
Reply to  Ryan Gibbons

Well, the radiator is circulating transmission fluid, might be good to know how much is in there and if the new radiator holds more transmission fluid than the old.   Does the new radiator itself hold more engine coolant than the old? If yes, when you add coolant you are replacing not only the coolant drained from the old radiator but also adding coolant to account for the increased capacity of the new radiator, if it in fact has a greater coolant capacity than the old radiator.   Same holds for transmission fluid.   Does the new radiator itself hold… Read more »

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