External coolers on a 2005 MDX

[Hokiefyd]

Since I was changing the radiator on it (link to relevant thread), I figured I might as well add a supplementary external transmission cooler while I was at it. And, after looking at it, I figured that I'd replace the cheesy power steering fluid cooler, too (which was just a long U-shaped tube).

That long U-shaped tube that spans the width of the opening is the power steering cooler. Gee, Honda, don't go out of your way for anything fancy, here.

Old power steering fluid cooler and bumper off...ready to start building.

These two holes right here (well, four, including the matching ones on the opposite post) would make great mounting points for some aluminum C-channel. More on that in a minute.

I gleaned some insight from our Ridgeline for this project, as it comes from the factory with power steering fluid and transmission fluid coolers in front of the condenser. The power steering fluid cooler is a simple two-pass serial flow cooler (like the MDX's U-shaped tube, but shorter, and with fins). So I figured that the smallest serial flow cooler I could get would suffice here for the MDX. The Ridgeline's transmission fluid cooler is a parallel flow multiplate cooler, much like a radiator in concept. So I bought a nice parallel flow multiplate cooler for this application to match it. Both were from Hayden and the shiny serial flow one was made in the United States and the black parallel flow one was made in Australia. Both appear to be very good quality. The pair cost about 100 bucks from Advance Auto.

I mounted the black one with stainless hex head cap screws and nuts. I mounted the shiny one through the fins, as it didn't have any mounting flanges. But rather than go through the condenser or radiator, I drilled small holes through my aluminum L-channel stock and zipped it straight to that.

Installed on the vehicle.

A close-up of the C-channel brackets on the side, and the L-channel stock mounted to them. I used .75" galvanized steel tube spacers to prevent any crushing, and used small .25" nylon spacers against the vehicle body.

Mmmm...shiny...

Nice and tight spacing in front of the A/C condenser.

And here we are, all geared up. The new Chinese radiator is installed, with new Mexican Dayco radiator hoses, and all coolers are plumbed with American 3/8" Dayco hose...a real international effort, this.

I went through a lot of 3/4" plastic wire loom that I just happened to have on hand. That was a good size to protect the 3/8" rubber hoses where they might chafe on something.

Everything fit nice. Disregard the black overspray in the bumper area -- that's a relic from an earlier install (when my folks had a front hitch bumper installed so they could tow this vehicle behind their motorhome).

The coolers centered up perfect in the lower grille opening.

My total cost for the entire job was about $325. $100 for the radiator, $100 for the two coolers, and another $125 for all of the new hoses, aluminum stock, and hardware. I used stainless steel fasteners throughout, and that adds up fast!

I spent a lot of time on this project this weekend, just test fitting stuff, going back to the store for something else, etc. Fabricating a solution like this is something that I enjoy immensely, and I had a great time in the garage this weekend. Looking forward to some turkey in another few days, now!

 

[Sunnyinhollister]

Looking good!

 

[HerrStig]

Hope you don't like your AC real cold.

 

[OneEyeJack]

Nice, neat job. I take it that you consider this car a "keeper".

 

[Mr Nice]

Nice work.

 

[Rand]

are you worried about overcooling in the winter?

 

[6starprez]

Nice clean look and I love that our state doesn't have front license plates.

 

[Hokiefyd]

Yes, this car is a keeper...or at least that's our intent right now. It's been in the family since it was new and it's just one of the best-driving vehicles we've owned. Despite being hauled around by its nose for many of its first 58,000 miles (so it has all sorts of excuses for giving us unconventional issues, like transmission or suspension problems), it hasn't missed a beat for the last 75,000 miles under our ownership (130k miles total).

I'm not worried about A/C performance, or about over-cooling in the winter. This is essentially the same as the factory setup on our Ridgeline, and is very proven in the world of Pilot/MDX DIYers.

I shot these with an IR gun after my wife and girls came home from dance class this evening, in ambient temperatures of about 40 deg F. The power steering fluid hoses were about 85 deg F on the inlet side and about 75 deg F on the outlet side. I couldn't get a good read on the transmission cooler hoses because they were too far above and below the narrow grille opening, but I shot the cooler itself, and it was about 150 deg F as far high as I could get on it, and about 115 deg F near the bottom, so that's a significant reduction in temperature.

From most places I've read, fluid temperature is one of the biggest predictors of transmission life. It's done fine so far for 130k miles, but I figure keeping it even cooler can't hurt.

 

[user52165]

Originally Posted By: HerrStig
Hope you don't like your AC real cold.


Are you inferring that his AC will be diminished by this installation?

No basis in facts. It doesn't work that way.

 

[Gasbuggy]

AC loses efficiency as you begin blocking air from the condenser. I'm unsure what your impact will be.

 

[KrisZ]

Very nice and clean install

Personally I would try to install the coolers vertically on each side of the radiator as close to the edge as possible. It's always best to keep the radiator and the condenser as clutter free as possible and those coolers don't need the same air flow as the radiator does.
Or since you already have them on a nice rail, I would move them to the edge of the rail on each side leaving the middle of the radiator nice and open.

 

[Hokiefyd]

They could probably be mounted a little further out towards the edges, but I did want to keep the rubber hoses from making too sharp of a bend. It's pretty cool here, so I admit that I can't test A/C performance. But again, this solution is very proven in the DIY world on these vehicles, so I'm not too concerned about it. If I have to make an adjustment next summer, it's easy enough to do.

 

[Lapham3]

Nice job-I think you'll be fine

 

[eclipsegst149]

The ridgeline came with the better cooler because of the extra weight it can haul, mdx was an option for the tow package. Looks good for DIY. I wouldnt worry about the a/c performance, will be just fine

 

[iluvhonda]

Good job. Enjoyed reading your write up.

 

[Colt45ws]

I like that install. Very professional. Ill keep this in mind if I ever need to add cooling to a vehicle.
So far, the factory coolers are doing a good job on my CVs.

 

[Hokiefyd]

Update...I'm getting leaks from the radiator hose clamps. I used the best ones I could find locally -- stainless worm gear clamps. Days after the initial install, I had to keep cinching them down a bit to keep the aftermarket Dayco hoses tight. We are going to make a 1,000 mile road trip this weekend, and something told me to pop the hood on the MDX and just check everything out. There's chalky blue staining around the radiator hose connections and around the clamps, and the subframe is wet behind the lower hose connection. Nice.

So, the Ridgeline is dispatched to road trip duty this weekend.

I never liked the fit of the Dayco hoses -- they don't quite have the same profile as the OE hoses. The upper hose especially seemed to be a little shorter than the OE hose, and kept trying to pull off the engine block connection, which is why I had to keep clamping that one tighter and tighter for it to hold. I think the hoses are the root of my problem, and over-tightening the worm clamps is the result. Seems like a common problem.

Since it seems that I need new hoses anyway, I'm going to go back to OE. I'm also debating which clamps to use. I still have the factory spring clamps. I may use those -- I had zero problems until I started putting aftermarket stuff on it. The Acura dealer said, "oh, I wouldn't use the spring clamps." Looking online and on BITOG, there seems to be mixed opinion on them. I'm going to give my factory ones a shot and see how they seal. If I have problems with them, I'll buy new ones, or re-assess then. But at least I'll have OE hoses back on it.

I probably shouldn't have replaced them to begin with. The old ones looked pretty much new.

Sound like a good plan?

 

[OVERKILL]

You want either the OE spring clamps or the Fuel Injection clamps, which are much better than a worm gear clamp (which are junk).

 

[SatinSilver]

Yep the ct(constant tension) clamps are the way to go along with oem hoses. The oem hoses can go an extremely long time. The worm clamps will need constant adjustment.

edit: from a very knowledgeable guy on an Accord forum:


Quote:
Leave the radiator hoses alone unless they are very soft or crunchy. If its used Honda coolant they should be in good shape. I've seen original hoses on these up to 300k and many years. You really didn't need to do the coolant again since you had the w/p done already. No harm done though, unless it was previously filled with other than Honda coolant.

If you want to change over to Redline D4 (since you're up in miles), you'll need enough to do 4 full drain/fills. Put the filter on the return line going back to the trans as any gunk will have already accumulated in the rad cooler.

The P1739 is the 3rd gear pressure switch for the trans if I recall correctly. The switch may have stuck and not sent a signal when it was supposed to.

 

[IndyIan]

The Tracker came with worm drive clamps on its rad hoses. They were tight enough to cut into the hose a bit, but everything has been leak free for 13 years now, with no adjustments. They've been off once 2 years ago, but still didn't leak.
I suspect they have been tightened hard enough initially to take all the slack out and have the clamp stretching a little like a spring.
With the clamps this tight, if there's any pulling on the hose it would probably start tearing around the clamp.