Questions on Installing a Coolant Filter (1 Viewer)

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Hey all, I'm about to totally overhaul my cooling system in my 1993 FZJ and I was surprised to find almost no threads on coolant filters. This is the only one I could find, from 14 years ago:

FZJ80 Coolant Filter Install

I don't really like this install for a few reasons:
1. It adds a lot of connections in an area that is already crowded and hard to reach
2. It mounts the filter pretty far away from where it is actually drawing coolant from
3. It is set up as a bypass system that tees off of the heater core system, which in a way is already a bypass of the main cooling system; I don't really see the advantage of adding a bypass system to a bypass system

So I pulled up Joey's great thread on coolant hoses and flow and did some thinking:

1FZ-FE coolant flow and planning

Now, my system is actually a little bit different, because it is a 1993; that means that the heater core return (the line coming from the firewall on the exhaust side of the engine) is not a hard pipe as shown in those photos, but instead it becomes a hose again to meet the housing for the main coolant inlet to the block. You can see what I'm talking about in this picture (stolen from this thread):

1587373346426.png


I was originally going to just replace it with the one-piece pipe, but then I had an idea; why not just use that spot to add in a coolant filter? I could just put a 5/8 hose on the end of the pipe, route that to the inlet of a filter base, which I would mount over where the washer bottle used to be. Then run a 5/8 outlet back to the inlet housing. Here's my professional diagram I made in CAD (and definitely not Microsoft Paint):

Coolant Diagram.png

What do you guys think of this? It would solve all of the problems that I outlined earlier. It adds no additional connections to the cooling system other than those at the filter itself, it's very close to the source of the coolant, and it's a bypass system (if the filter clogged or leaked, your heating system would stop working but your engine would still be getting coolant). I'm still considering what filter base to use, and I'll update this thread when I make a decision.
 
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I guess the question is why?
This seems like a solution looking for a problem.
I mean, you can ask those same questions for oil and transmission filters (I know the FZJ doesn't have an external trans filter, but it does have an internal one of sorts), and many of the same answers apply to the cooling system. There is crap that gets in the coolant; hoses break down, the additives break down, corrosion from an aging radiator or heater core, and a litany of other things. If you look at that first thread I linked, you'll see the evidence of that, in the form of all the gunk that he was able to catch with the filter. There's a reason why pretty much EVERY commercial vehicle has a coolant filter. I can't find it at the moment, but I remember reading a FleetGuard brochure a while back that claimed 50% of engine failures were due to cooling system malfunctions; it's no secret that debris in the system is a large contributor to these malfunctions.
 
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I mean, you can ask those same questions for oil and transmission filters (I know the FZJ doesn't have an external trans filter, but it does have an internal one of sorts), and many of the same answers apply to the cooling system. There is crap that gets in the coolant; hoses break down, the additives break down, corrosion from an aging radiator or heater core, and a litany of other things. If you look at that first thread I linked, you'll see the evidence of that, in the form of all the gunk that he was able to catch with the filter. There's a reason why pretty much EVERY commercial vehicle has a coolant filter. I can't find it at the moment, but I remember reading a FleetGuard brochure a while back that claimed 50% of engine failures were due to cooling system malfunctions; it's no secret that debris in the system is a large contributor to these malfunctions.
These systems are not designed for a cooling system filter.

A filter in this system is a restriction. The water pump design on these vehicles is a centrifugal pump design. With too much restriction, they will cavitate. Cavitation means no flow. In your case, you are looking to create a bypass to the filter. In order to prevent cavitation, this filter area would have to be very large with a very high flow rate. What particulate size are you looking to remove? That relates directly to the flow rate. The unit will be on bypass most of the time (of course you cannot KNOW that because it's a closed system) and it creates another maintenance item that you have to drain the coolant to change.

Secondly, the cost of installing a coolant filter on a vehicle designed without it would be cost prohibitive. Just change the coolant every 2-3 years and be done with it.

While it is important on a diesel OTR truck that run 10 million miles in a lifetime, it makes more sense because they put on more miles in a year than these trucks will see in a lifetime.
 
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I just drained my coolant and it's still squeaky clean after 2 years service. I agree with @jonheld, what's the point? Yes, crud will eventually get in there as things break down, but that's why you don't leave your coolant in forever. It is a service item. Crud floating around in your cooling system isn't going to catastrophically damage your motor like crud in your engine oil--that's probably one of many reasons why most vehicles are engineered with engine oil filters but no cooling filters.

:edit: I would bet the guy in that thread you linked had something going on to regularly generate crap in the system like that. Either a failed bargain basement radiator, hoses not rated for coolant, some weird additives or something. I just pulled an ancient (maybe original?) copper radiator and it looks perfect inside. I flushed some brown crud out of it two years ago at the last coolant change with a garden hose. I believe the cause was mixing red and green.
 
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These systems are not designed for a cooling system filter.

A filter in this system is a restriction. The water pump design on these vehicles is a centrifugal pump design. With too much restriction, they will cavitate. Cavitation means no flow. In your case, you are looking to create a bypass to the filter. In order to prevent cavitation, this filter area would have to be very large with a very high flow rate. What particulate size are you looking to remove? That relates directly to the flow rate. The unit will be on bypass most of the time (of course you cannot KNOW that because it's a closed system) and it creates another maintenance item that you have to drain the coolant to change.

Secondly, the cost of installing a coolant filter on a vehicle designed without it would be cost prohibitive. Just change the coolant every 2-3 years and be done with it.

While it is important on a diesel OTR truck that run 10 million miles in a lifetime, it makes more sense because they put on more miles in a year than these trucks will see in a lifetime.
I am not a cooling system engineer, but I think that the odds of causing the pump to cavitate by adding a slight restriction to a 5/8 auxiliary line, when the comparatively gigantic radiator hoses are still there and open, is HIGHLY, HIGHLY unlikely. Sure, if you used one of those inline filters that you chop your radiator hose in half and stick it in, I could see cavitation problems (I think that's a horrible design to begin with). I still agree that you should use a higher flow filter, and pretty much all of the coolant filters on the market are going to be plenty big enough as they are capable of filtering much bigger cooling systems.

I don't really see the cost as very prohibitive, as I think the whole job can be done for around $100.
 
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I am not a cooling system engineer, but I think that the odds of causing the pump to cavitate by adding a slight restriction to a 5/8 auxiliary line, when the comparatively gigantic radiator hoses are still there and open, is HIGHLY, HIGHLY unlikely. Sure, if you used one of those inline filters that you chop your radiator hose in half and stick it in, I could see cavitation problems (I think that's a horrible design to begin with). I still agree that you should use a higher flow filter, and pretty much all of the coolant filters on the market are going to be plenty big enough as they are capable of filtering much bigger cooling systems.

I don't really see the cost as very prohibitive, as I think the whole job can be done for around $100.
Knock yourself out and report your findings! Maybe it will help the next person considering this.
 
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Knock yourself out and report your findings! Maybe it will help the next person considering this.
I am really leaning towards trying it, as I know there's currently gunk in my cooling system from mixing green and red. If it does nothing, I can easily just take it out and put a piece of hose back there.
 

Tachycardic

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Just wondering...what are you trying to achieve? Are you trying to extend the life of the radiator or water cooler? Unless you're mixing coolants, or using things you shouldn't be, OEM already lasts many years to decades. There's a reason why you haven't found a bunch of threads about coolant filters and the 80--they're not needed.
 
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Just wondering...what are you trying to achieve? Are you trying to extend the life of the radiator or water cooler? Unless you're mixing coolants, or using things you shouldn't be, OEM already lasts many years to decades. There's a reason why you haven't found a bunch of threads about coolant filters and the 80--they're not needed.
Like I said elsewhere in this thread, just trying to remove the particulates that can build up in the cooling system over time. And the PO did mix red and green in mine so there is some brown stuff; I am planning on doing a flush, but that will never get 100% of the stuff out.
 
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I am really leaning towards trying it, as I know there's currently gunk in my cooling system from mixing green and red. If it does nothing, I can easily just take it out and put a piece of hose back there.

The PO of mine mixed red and green also.

I ended up with an exploded radiator because of that and the old parts still in the system.

I flushed with a garden hose in every orifice, both directions until it ran clear. (Realize a garden hose is pushing 60 PSI and your cooling system is only designed for 14 PSI, so DON'T seal it when you do that.)

Then I filled with distilled water (I left out the thermostat for most effective flow) and drove it 40 miles, let it cool most of the way, then pulled a lower radiator hose and the block plug to COMPLETELY drain it. I did the SIX times before it was nice and clear.

Then I installed the new OEM T-Stat, filled it with Toyota Red and it is still nice and clear, almost a fruit punch Gatorade look, 6 years and 80K miles later. Mind you, I installed almost ALL new hoses, and a new OEM radiator at the time. Also make sure you use a new OEM radiator cap and that it has PROPER fitment to your radiator. The cap not relieving can explode the system.

Then make sure you "burp" the system when complete to get out all the air bubbles.
 
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There is absolutely no comparison between having an oil or tranny fluid filter, and a coolant filter. The tolerances inside the transmission valve body and inside the bearing journals of an engine are extremely small (~12microns IIRC).

There is no place in the cooling system that requires micron filtration. There are no tolerances that tight. The water pump is a centrifugal pump that does not have tight clearances. There is no valving or porting that is critical.

Engines ingest air that; though filtered, still contain particulates that make it into the oil. The water system is sealed...

I think that this is a non-issue...
 
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The PO of mine mixed red and green also.

I ended up with an exploded radiator because of that and the old parts still in the system.

I flushed with a garden hose in every orifice, both directions until it ran clear. (Realize a garden hose is pushing 60 PSI and your cooling system is only designed for 14 PSI, so DON'T seal it when you do that.)

Then I filled with distilled water (I left out the thermostat for most effective flow) and drove it 40 miles, let it cool most of the way, then pulled a lower radiator hose and the block plug to COMPLETELY drain it. I did the SIX times before it was nice and clear.

Then I installed the new OEM T-Stat, filled it with Toyota Red and it is still nice and clear, almost a fruit punch Gatorade look, 6 years and 80K miles later. Mind you, I installed almost ALL new hoses, and a new OEM radiator at the time. Also make sure you use a new OEM radiator cap and that it has PROPER fitment to your radiator. The cap not relieving can explode the system.

Then make sure you "burp" the system when complete to get out all the air bubbles.
Yep I am basically going to do the same thing, except I don't actually have access to a hose so I am just going to do the fill/run/drain method a bunch of times for flushing. I also have 2 bottles of the Prestone coolant flush, I am planning on running one with the old components still on and then 1 with the new stuff on before I flush it with water one last time and then finally fill it with the red. I have pretty much every part for the cooling system: new radiator, radiator hoses, every other hose, Aisin water pump and gasket, Aisin thermostat and gasket, brand new cap, and red coolant (mine is the Valvoline stuff just because I can't really afford Toyota brand, nor do I have easy access to getting some).

Edit: adding the filter will be the last thing I do, right before I fill it with the red
 
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Yep I am basically going to do the same thing, except I don't actually have access to a hose so I am just going to do the fill/run/drain method a bunch of times for flushing. I also have 2 bottles of the Prestone coolant flush, I am planning on running one with the old components still on and then 1 with the new stuff on before I flush it with water one last time and then finally fill it with the red. I have pretty much every part for the cooling system: new radiator, radiator hoses, every other hose, Aisin water pump and gasket, Aisin thermostat and gasket, brand new cap, and red coolant (mine is the Valvoline stuff just because I can't really afford Toyota brand, nor do I have easy access to getting some).

Edit: adding the filter will be the last thing I do, right before I fill it with the red

You know, now that I think of it, I might replace the non-hose components (radiator, heater valve, water pump, thermostat) BEFORE I do any flushing. I think there is probably gunk caught up in them (especially the radiator), and I feel that by flushing I might actually just be breaking it loose to go get stuck somewhere else.
 
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yes , yes , yes, you definitely need one, no put two better tree filters, this particular engine notorious for overheating under load will fitted help ya to keep coolant clean? perhaps so , you will have a clearer coolant, will filter create a restriction flow - yes it will so prom to run hotter! I do not see the problem with dirty coolant, but see the problem running hot.
 
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yes , yes , yes, you definitely need one, no put two better tree filters, this particular engine notorious for overheating under load will fitted help ya to keep coolant clean? perhaps so , you will have a clearer coolant, will filter create a restriction flow - yes it will so prom to run hotter! I do not see the problem with dirty coolant, but see the problem running hot.
Not to be rude, but could you speak in coherent sentences?
 

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