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Magnefine before or after the cooler?

9963 Views 53 Replies 17 Participants Last post by  sulkair
I did a search on this and really didn't come up with that much, sorry if I missed it. I also posted it in another thread and nobody responded

If I installed a B&M cooler, temp gauge and Magnefine all at the same time on our higher mileage Ody, where should I put what? My plan is to put the temp sensor right after the fluid comes out of the tranny and before the radiator. Then I'd put in the Magnefine after the fluid comes out of the radiator, then send it from the Magnefine to the cooler, and from the cooler the fluid would go back into the tranny. My reasoning is that I wouldn't want a bunch of crap clogging my new cooler. But the general consensus seems to be that I should install the Magnefine after the cooler and right before the fluid goes back into the tranny. What should I do?
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Before your new cooler is fine.

The general instructions are to put before the cooler if less than 5000 miles on the vehicle and after if more...
But this refers to the in-rad cooler. Since you are adding a brand new cooler you can indeed place it before the cooler if you want so as to protect it from any debris...
Generally, when installing an ATF filter in an existing system, you install it in the return line to the sump. In other words, install it in the line from the cooler (radiator or existing additional cooler) to the sump. The idea is to remove all crap that is being flushed out of your system just before the sump, and supply clean oil to the pump pick-up. So you just snip the hose, insert the filter, install a couple clamps and you’re done. You may also need to support the filter, but probably not.
If you are also installing an additional cooler, install the filter downstream of the existing cooler (radiator), and upstream of the new cooler (the other side of the new cooler returns to the sump). This way you prevent deposition of crud in your new cooler.
I would install it before the cooler since hot oil is less viscous and would be easier to filter. And there shouldn't be crap coming out ouf the cooler, that's a passive piece!
I'd install it in which ever line gives you a cleaner, safer, more obstruction free install. Debris can collect in the (in-radiator) cooler, but if you've got that much solids in there, the trans is toast anyway. FWIW, every service manual trans replacement I've ever seen calls for replacing the radiator or doing a thorough 'purge' of the in-tank cooler.

Laphroaig said:
I would install it before the cooler since hot oil is less viscous and would be easier to filter. And there shouldn't be crap coming out ouf the cooler, that's a passive piece!
That's contrary to Magnefine's instructions. Perhaps since its a magnetic filter, it filters better at cooler temps.
Laphroaig said:
And there shouldn't be crap coming out ouf the cooler, that's a passive piece!
The cooler doesn't produce crap, but it can trap crap and then release it back to the transmission where it can cause sudden death. That's why a cooler flush is part of every tranny replacement.
dvpatel said:
That's contrary to Magnefine's instructions.
Um... No. It's not.

The instructions read: "On new vehicles (less than 5,000 miles), it is recommended that the filter be installed on the cooler supply side to protect the cooler from contamination. On in-service vehicles (more than 5,000 miles), the filter should be installed in the return line from the cooler to the Transmission."

So the intent is to filter the fluid as it is returned to the sump so that clean oil is pumped back into the tranny. If the cooler is new (<5000 miles) you can prevent crud deposition in the cooler by filtering upstream of it. If the cooler is not new (>5k) then you go downstream to prevent previously deposited stuff from releasing back to the sump.

From mechanical and chemical engineering points of view, heat exchange surfaces will tend to suffer deposition of certain constituents.
I was actually agreeing with you. If the cooler is new put it before. If not, put it after is what the magnefine instructions say like you posted. I quoted Laphroaig's post and said its contrary to Magnefine's instructions because his post instinuates that its OK to put it before the cooler regardless of whether the cooler is new or not. I suppose the intent is to prevent contamination of the new cooler but if its over 5K miles old, then Magnefine assumed that its contaminated and hence put it on the return line may be?

Now that I read my prior post though, it doesn't make sense about the cooler fluid though. I am not sure why I posted that bit.

Laphroaig said:
I would install it before the cooler since hot oil is less viscous and would be easier to filter. And there shouldn't be crap coming out ouf the cooler, that's a passive piece!
Just out of curiosity (really), how did you find this 2 years later?

I think I'll disagree a bit doesn't matter if it's a "passive piece", it can still accumulate debris. It can also shed debris downstream in large slugs under the right conditions. I've cleaned out one of these before when I installed a Hayden ATF cooler on our Accord. Surprising amount of stuff in there.

If you've got some miles accumulated (like on the OP's "higher mileage" Ody, I'll say that Magnefine's instructions for installing it downstream of the OEM radiator in-tank ATF cooler seem to be on-the-mark for that situation.

I've only observed a cooling delta of about 9 degrees (median value) from the OEM radiator in-tank ATF cooler...I just don't think that small value will contribute to a measureably significant change in viscosity.

Any other inputs from the knowledgeable Ody owners out there?

0dyfamily said:
Just out of curiosity (really), how did you find this 2 years later?
Did a search with Magnefine.

For the tech part, transmission wear is a slow process. There is very few steel particles that wears off the transmission for each complete oil cycle across trans/cooler/pump/hose/etc. I do belive that the key is to remove as much of that steel everytime it passes through the filter than filtering it before or after the cooler since it's the cummulative and not the instant effect that is the problem. I don't belive that coming out of the transmission, the oil is completely contaminated and nearly useless and that with a simple filtering, it rejuvinates! I'm sure that the oil in my Ody can make many cycles in and out of the transmission and UOA wouldn be able to find any difference between cycle 0 and cycle 100.

But oil viscosity as it exits from the trans is lower than after it has cooled in two coolers. As it's easier to remove steel particles from water than from molasses, it's easier to do so with hot oil than cool one.

Finally, if those steel particles accumulates in the cooler from the transmission, why would that completely change the minute there's a filter somewhere?

1-oil contamination is a slow process.
2-To prevent contamination, we must filter oil as much as we can, continuously
3-If there's dirt in the cooler, it won't come off instantly the minute we install a filter.

i would guess that there's an equilibrum on contamination across the oil "cycle" and the oil itself. I would be suprised to see a dirty cooler with an ultra clean trans. The transmission will slowly generate steel particles. Oil will spread it where it passes. Let's say we change the cooler, oil will slowly contamnates it with steel. Add a filter and we slowly remove dirt.
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Thought I'd ask the rhetorical question just to show that our Search function is a great feature!:D It rocks.

On the note of the topic, it wouldn't change a thing...except you now have a filter, so why not put it some place where it can potentially do the most good? The OP has a higher-mileage car. If it were brand new, I'd toss it on the line immediately exiting the AT, for sure (so it can do the most good and maintain the cleanliness of the the already-clean part of the circuit) but that's not the case's an older Ody. There's stuff in the cooler.

Still, anybody out there who can tell me if a 9-degree Fahrenheit difference is going to change the viscosity appreciably? I don't think it will. I don't think that ATF at 131F is going to be a whole lot different than ATF at 140F, for example, in terms of viscosity. Downstream of the OEM radiator in-tank cooler, per the instructions, seems to make good sense to me for this older Ody. The OEM radiator in-tank cooler isn't much of a cooler. Sometimes, it acts as a heater, at least according to my thermocouple thermometer.

Are you sure it's easier to filter thin oil than thick oil? I'm guessing you meant to say that thick oil will flow with more difficulty, all things being equal, right? The filter media will still catch particulates, hot or cold, as long as the ATF is at a temperature supported by the media (i.e., it's not so hot as to exceed the temp at which we could see degradation of the filter media).

I mean, we install these things for two reasons, as you pointed out:

1.) Continued filtration of particulates in solution
2.) Ability to stop a large amount of stuff, should it get dislodged.

Last I recall, when I cut apart an OEM radiator in-tank cooler, there was just a lot of dark, fine stuff that had the consistency of pond silt laying in there. I can appreciate wanting to not allow any of this to run back to the tranny, should any of it become dislodged (via vibration, road shocks, etc.).

I think one our forum members (theojo) cleaned one out as well, and had the same results.

Any other people who've cut one apart or cleaned one with similar experiences?

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I just don't think that there will be chunks of something coming out of the cooler.

And i think that the filter efficiency is better when oil is the hottest than when it's the coldest.

And I would expect the filter to slowly remove dirt (that could be trapped by it!) and this way cleans parts that are in contact with it.

I trade a chance of being protected should an unidentified/unseen thing coming out of the cooler for a better filtration efficiency (essentially, filtration made by the magnet).

Edit after your edit : I would put my filter after the AT rather than after the coolers. I expect the oil temp going out of the AT when there's the most wear, i.e. under load, would be much higher than the oil temp after the coolers.

I said viscosity, but I guess the chemical bond between oil and steel changes with temp too.

As for the filtration, as I wrote in my reply while you were editing yours, I talk about filtration made by the magnet, not the filtering media. I guess the only thing that really matters with the filtering media is whether or not it is bypassed! The oil pump is a constant displacement one and will provide the pressure needed at a given rpm whatever the oil viscosity is.

Would be interesting too to know if someone somewhere ever saw or had a situation where a big chunk of sludge/deposit/?? broke apart from somewhere in the oil line to damage the transmission. It's like searching someone who actually had a problem with a Fram filter!!! :)
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You could solve either of the two arguments by simply installing a second $15 Magnefine filter (one for each line).
Early on replacements for gen2 Ody's under dealer extended warranty provisions did not clean out the radiator ATF cooler which resulted in subsequent failures. Later on, they included instructions how to "flush it out" and included a Mickey Mouse in line cigar sized "screen" filter for the ATF mounted on the lower radiator output line. Point is, junk embedded and later dislodged will shorten the life of a tranny.
herrhaus said:
You could solve either of the two arguments by simply installing a second $15 Magnefine filter (one for each line).
...or flush all that stuff out of the cooler (JUST the cooler, don't flush anything else).

edited to add this:

herrhaus, I think you know I'd be the last to stir up the poop...but from all I've gathered data-wise, I still don't have data to show if the viscosity poser is relevant.

I mean, I've seen well over 200F on the ATF leaving the A/T, and even though our 2002 EX has the additional OEM ATF cooler, the best steady state cooling Delta I've seen is about 18F (10C).

Not insulting anybody's expertise or enhanced knowledge on the subject, but I'm just skeptical...I just don't think that under normal benign driving conditions (IIRC, about 70F OAT, 68mph, no A/C, approx 200F ATF outlet temp, 180F to 185F ATF return temp on my last data-observing trip), I don't think the ATF will undergo that much of a viscosity drop...but like I said, I don't have a lot of knowledge on that part of the equation. That's why I'm asking for somebody to give some hard data. I'm just skeptical over the impact it would have on our situation.


P.S. herrhaus, I'm selling the MR2 beatermobile. Just cannot function with only two seats while my 2003 Ody is down for ATF & PSF cooler installs! I have a minimum of me and two kids with me on most short around-town trips. I've tried it on a trial basis with the '03 in the garage, and it's a no-go situation. That used '98 Ody is lookin' like what I need....

Also, don't laugh, but I've got a HECAT heat exchanger flusher to attach to my shop compressor. Once I get a set of wheels and start tearing apart the Ody, I'll post a progress report on how well it handles the OEM radiator in-tank cooler.
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I tend to agree that magnetic filtering will be better if the fluid is hot rather than cold since its easier for the magnet to draw the particles out of a less viscous fluid as it pass's by the magnet..

Having said that I also agree that the difference between the viscosity at the point the fluid exits the AT and point it re-enters isn't that much different. AT fluid is a very light weight oil to begin with and no matter what the output and return temps will only be about 20F different..

Now for non magnetic filtering like a plain oil filter I don't think it makes any differnce at all. If it remove particles of a specific size it will do so no matter what the viscosity of the fluid.

I installed the magenfine on the return line because the return line was a much easier location seeing as it was just a straight peice of hose from the rad back to the tranny... I couldn't see a good location in the line from the tranny to the cooler..

Before or after isn't the most important point, just installing one is...

The combination of the magenfine plus a true thermostatically controlled ATF cooler have kept my ATF fluid in great shape..
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bb5, I get the feeling that you, Laphroaig, herrhaus, and many other posters must have some sort of engineering background (I myself do not).

Just a complimentary observation, based on what I've read from everybody's posts.

I'm convinced by all of you...when I clean my heat exchangers (when I do the big ATF cooler install), I'm going to put that filter on the line coming out of the transmission (before the coolers).


P.S. Or attain internal harmony (mine, not the car's :D ) and do like herrhaus said and add a Magnefine before and after!
Now just hold on a are giving me way too much credit. First of all, I don't have a a Magnefine installed before and after on mine....just after. Secondly, I was only being a smart donkey and stating the obvious. :)

Thanks for the compliment.....however, while I may have an engineering background.....I ain't a mechanical engineer.....I'm a civil engineer silly. ;) :) ......and......I'm still trying to find the stupid train. :stupid:
I have a simple question. I plan on adding this filter to my return line next week. I am ordering the filter on Monday. How can I identify the line I need to splice it into? Is it a rubber line? Is this an easy process? What type of time am I looking at? If my trans blows after I put this on, will HONDA try to void my warranty?

My main question is about the installation
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