85 PICKUP

I recently installed a Hayden 677 transmission cooler to bypass the internal one in my 99' 4Runner V6 4x4 with 163k. I am a little paranoid as it doesnt seem like a very popular choice and I am worried its too small.

Both the parts and a tranny shop guy advised that it was fine.

http://www.summitracing.com/parts/HDA-677/

I dont do any towing aside from a utility trailer for the occasional yard work and home improvements. And I live in Oregon so for the most parts its fairly mild temps. Dont really wheel it either, pretty much use it to commute back and forth to work.

I've seen a cut away view of the internal radiator ones and the Hayden seems much bigger if that means anything.

kball

That's the same size as the B&M 70268 I installed and I believe it's the same as the Tru Cool 4454 as well.

dgz32

Yep, that's the same size as my Tru-Cool 4454 - looks identical, actually. Mine has been great for commuting. However, I have a trans temp gauge installed and have seen temps spike beyond my comfort level while climbing prolonged steep grades on pavement. I'm currently looking to go with a thicker core.

|dg

FogRunner

It's really important with using a external transmission cooler is your fan clutch must be in 100% working order. If you don't hear the vroooom of the fan when you take off at a traffic signal, then your fan clutch is bad.

Its really easy to misdiagnose a cooler as being too small because of a marginal fan clutch. If your fan clutch is more than a few years old chances are it needs to be replaced.

The old test of spinning it with it turned off isn't always a good test. The way to test it is to do a bit of city driving in warm weather. Then stop the car and open the hood and rev up the motor a couple times and hold around 1500-200rpms. You should feel the fan moving ALLOT of hot air.

If your fan doesn't keep moving allot of air at 1500 rpms for more than a few seconds then it needs replacement.



FOG

quicksilvr

Does $140 for an OEM fan clutch sound about right? I need to replace mine, and I figured this was a part that was probably only available OEM. And if it is available cheaper aftermarket, probably worth the extra $$ for OEM quality on a part like this.....

FogRunner

I bought a Hayden fan clutch at Oreillys with a lifetime warrant for $130.00 and IMHO its on par with the OEM in quality. I would spend the money at oriellys and get the lifetime warranty.

FOG

dgz32

You've got a point there. I didn't change the clutch with my timing belt job last year. I can hear it roar in the mornings...but I have no idea if/when it's been replaced.

|dg

FogRunner

My old one would roar in the morning but once it got hot it didn't move much air at all. After driving around a bit it should roar every time you take off at a stop light.


FOG

85 PICKUP

Did you have your trans-temp gauge before the cooler install? I wonder what the temps were before the bypass.

The external cooler has to be better than the internal one regardless I would think. Mine is mounted in front of the AC condensor right behind the grill so it gets blasted with air.

ft_surgn

Having similar concerns...

Just finished the milkshake-preventing maintenance last night, and while re-loading the anti-freeze, we didn't get any fan engagement. Driving around today in the city shows steady temps, but when I got out, I put my hand on the hood and immediately retracted it; my hood was very hot!

Does this mean it's time for fan clutch replacement? What would happen if the clutch weren't replaced?

What effect does the external cooler have which suddenly makes an ok clutch non-functional?

CLin9383

i have the 1678 in my 4runner and it is the biggest you can fit without doing other mods. My hood has always been hot, when it rains if you look carefully you can see smoke coming off my hood from the rain cooling it or whatever and this is more prevalent in the winter time as my hood will have no snow on it after a while.

dgz32

I didn't have the temp gauge installed before I did the bypass, unfortunately. Last summer, just after I installed the TruCool cooler, I was at 210+ degrees and climbing after running an uphill grade for several miles on pavement. It was pretty steep, and temps fell quickly on the other side - still, I was very uncomfortable watching that needle.

That said, I took FOG's advice and picked up a Hayden fan clutch - $74 shipped from RockAuto, btw. Also bought the B&M unit with the thicker core. Both will be going on this weekend - along with plugs, wires, O2 sensors, fuel filter, and a battery

|dg