coolant filter question

[79jasper]

Personally, I would change it.
But I would have to say blend door also.

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[LCAM-01XA]

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Just not sure to switch it or leave it or if it makes a difference odd?

Is this how yours is set up right now? If yes then you got it right. Tho like Riot said the core itself doesn't care which of its ports is inlet and which is outlet, on the same truck we've had it both ways depending on how the hoses routed better and I can assure the truck may have 99 problems but lack of heat sure as heck ain't one

Really the only way to plumb the system wrong is to inline the filter between the heater core and the water pump - when the filter gets plugged up the coolant flow backs up in the core and under high engine speed the core may go ****. Filter inline between engine block and heater core is perfectly okay tho, that's how you do it if you wanna use heater core output as an indicator of how plugged the filter is - not quite how the filter is meant to be used, but seems to work just fine.

 

[Fixnstuff]

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Just not sure to switch it or leave it or if it makes a difference odd?

This is my first post to Oilburners and I chose to reply to your post because of the Topic and the diagram you presented. Without knowing the flow rates that your filter head and filter are capable of handling, nor the flow rate coming from the engine head to the heater core, ('technical data') I will say that your installation diagram is the safest way and in the absence of technical data to show otherwise, it is the correct way to connect a coolant filter. You don't need to change anything. I can suggest a minor improvement I came up with in a later post when I describe how I will be installing mine.

 

[LCAM-01XA]

Fixnstuff, I think Eric's concern wasn't so much whether to switch his bypass to full flow, but rather which port of the heater core is inlet and which is outlet. Which should never be a concern on these trucks, since the ports are the same size and so are all hoses - route them any which way works best for you, as long as one is in and one is out and the core is clean internally there will be plenty of heat coming out the vents. And if too much hear is coming out without the engine actually overheating, then the issue is not in the coolant loop but rather the blend door - likely the cable sheathing has slipped in its clamp and thus changed the end position of the blend door, it's an easy fix once the glove box has been swung down out of the way.

 

[Fixnstuff]

'How To Install A Coolant Filter' is one of the most screwed up and hair-pulling topics that I have yet encountered on diesel forums. I'm focusing entirely on 6.9L and 7.3L IDI engines because I've not studied the Power Strokes and later systems which are different. The main reason for the confusion is the ever increasing backyard advice to install the filter in-line in one of the heater core hoses, advice which I have yet to see any technical knowledge or reasoning whatsoever to support this other than 'it's easier' 'I'm too lazy to connect it the other way' (apparently it looks like it will work) and by using this connect the dots method, these are the fewest dots. I intend to show good technical reasoning and explanations why not to install the filter in-line with a heater core hose. Anyone who has taken the time to study this subject at length just from the topics on various diesel forums should be aware of at least a couple of reasons suggesting why it should not be installed in-line and I think I can affirm and add to those. My perceptions are based on some significant technical knowledge and background. I have not performed any tests to prove these perceptions but they are fairly common and basic knowledge in fluid dynamics. When I am ready to install my own filter system plus a 4 port a heater core bypass controlled by existing heater A/C controls on the instrument panel (a bit complicated) I will do some tests to prove or confirm that my perceptions about the coolant filter setup are right or wrong, including a possible improvement to increase coolant flow through a filter connected in parallel (like the diagram posted by ericwade381. In any case this should be an interesting discussion.

It's late at night, I am very tired (I write to much when I am tired) and I am going to take a rest break before I resume my comments. If I fall asleep I'll be back tomorrow. I plan for my next post (or two) to cover all of the issues that I am aware of, explained in terms that are easy to understand.

I am a perfectionist at nearly everything I do and I like to do things at least the right way and beyond that, the best way that is practical to achieve. I'm passionate about restoring my truck and making it a very nice truck doing the best I can. On very low income disability I cannot afford to buy a very nice newer truck but making the right decisions I can restore this 1987 truck over time and it will be just as nice as the much newer ones, so this is it, "My very nice truck project."

My sole objective in this topic is to get the confusion about coolant filter setups sorted out so others will have more information to make better decisions and maybe we can improve upon the systems we have now and possibly invent better ones.

 

[Fixnstuff]

Fixnstuff, I think Eric's concern wasn't so much whether to switch his bypass to full flow, but rather which port of the heater core is inlet and which is outlet. Which should never be a concern on these trucks, since the ports are the same size and so are all hoses - route them any which way works best for you, as long as one is in and one is out and the core is clean internally there will be plenty of heat coming out the vents. And if too much hear is coming out without the engine actually overheating, then the issue is not in the coolant loop but rather the blend door - likely the cable sheathing has slipped in its clamp and thus changed the end position of the blend door, it's an easy fix once the glove box has been swung down out of the way.

THANK YOU. I didn't see a few of these posts that came up while I was writing my last one. Eric's diagram looked correct to me - the hose going to the top of the water pump is the return hose from heater core- the bottom hose in his diagram and that is an important one as I will mention later. I've spent some time studying the cable controls, vacuum motor controls, A/C circuits etc. from the 87 Shop Manuals to figure out how I am going to tie in a 4 port heater core bypass valve- controlled by vacuum motor, cable or electric from existing controls on the heater A/C panel. Somewhat complicated. The easiest way is electric servo and just install an additional dial knob on the dash like some modern temperature controls, left (blue-cold) = complete heater core bypass for maximum A/C cooling in the cab (for very hot climates) and to the right (red) to gradually go to full open through the heater core for maximum heat in cold weather- thus having variable settings. I wanted to tie this into existing controls but haven't figured that out yet- or if it can be done. Enough on that because it is off topic.

By the way, I am not used to this forum software. All I am getting is a 'Quick Reply' window. Is that the standard? Thanks.

Cancel that question. I SEE NOW! I CLICK ON 'ADVANCED'

 

[LCAM-01XA]

This should get interesting. Our trucks are all done with the bypass setup, I was just looking at the IDI and thinking that even if we are to switch it to full flow the hoses routing ain't gonna run any different so there's really nothing to be gained from doing so.

Regarding your project with the heater core shutoff - what works against you is that your 87 has full mechanical HVAC doors control, both the 86-down and the 89-up models use vacuum servos and so running a 4-port valve with a vacuum can T-eed into the fresh air door vacuum line is the standard practice, but obviously you can't do that. What you can do is use a 4-port valve that is cable actuated, and hook that up to the recirculating door lever - when the door is closed so is the heater core for max A/C effect. The one thing I don't like about this setup is the same thing I don't like about the vacuum T-ee - sometimes it's nice to have the door closed AND the heat running full blast, if the bypass valve is slaved to the door actuator that's impossible to accomplish. Of course most folks have no issue with that cause from the factory the fresh air door is closed only on the "max a/c" setting (well, and "off"), but for trucks like yours where the door is manually controlled you could do the "max heat" trick easily. And I wouldn't wast time on a variable coolant flow setup - make it a simple on/off instead, cause when it's fully on you can still vary your vents temperature via the blend door anyways.

Also a heads-up, I'd highly recommend that you do NOT use the aftermarket replacement diverter valves you can get from the parts store for like $20 or so, they are very hit or miss things as far as quality goes.

 

[Fixnstuff]

Sooooo here is a question guys I notice that my lines are opposite of this routing. Looking at the truck the far right hose goes to my water pump and the left outlet goes to my block?? This shows opposite of what someone did on mine? Would this explain why my truck always blows hot air or is it maybe right?

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Your Attachment link does not work. Try to fix it if you can! I incorrectly thought that the diagram in your following post was the attachment you had first attempted. That diagram is correct. Standing in front of the truck looking at the Heater Core connections, the Hose on the LEFT toward passenger side is the RETURN HOSE to the WATER PUMP. The Heater Core connection on the RIGHT (toward he Drivers side) should be the hose coming from the Engine Head passenger side or the 'block' as shown in the diagram in your post that followed the one quoted here.

From what you wrote above it seems that they may have been connected backwards. The heater core may not care even as it is being back-flushed due to the reverse conncetion and any crud that comes loose will go back down to the water pump and pushed through the engine - but to someone working on the truck at any time in the future it could make a big difference if they didn't notice the hoses being connected wrong. It would make a big difference to me when installing a 4 port heater core bypass if I didn't notice it. My perception of IN and OUT hoses would be completely opposite to the way yours ia apparently is hooked up, so yes it makes a difference.

Are you SURE it is hooked up that way?

This would make no difference on the heater blowing hot air as others have suggested.

If it really is hooked up backwards though, I would suggest that you change it at the heater core ends to make it correct.

 

[Fixnstuff]

The coolant filter is used in a bypass mode- parallel to the return hose. Use two Tee's on the return side hose, the filter gets plumbed in between the two Tee's. The filter head should show an IN and an OUT flow arrow or text, the IN side connects to the Tee closest to the firewall..

INTERESTING, BioFarmer93. I don't recall seeing that configuration before but it seems great for mounting the cooler on the inside fender- about where the base of screw jack would be. Less intrusive than parallel between both hoses.

I wrote lot's of comments relating to this and other things pertaining to filter setups but I got way too tired to finish it so I had to cut it from my reply and save it for a new post sometime later tomorrow- or that is, later today. It's almost 4 AM here.... up too late being obsessed with truck stuff (again)

 

[Fixnstuff]

....

Blows hot cause blend door not functioning is my best guess

I agree! (as did one or two other people)

Eric, you can start by checking the the vacuum motor connector that controls the outside air vent/recirculation door. Look above the heater hoses on TOP of the black plastic cover (so tired I can't think of the name of it) right in the corner by the hood hinge. There is a small vacuum motor, looks like it has a small wire on the back but that is a tiny vacuum line. On the firewall side there is a flat metal mechanical bar with a hole in the end- that hole fits over a plastic pin that opens the vent door below to outside air or closes it to recirculate the air inside the cab. Sometimes the clip that holds it on breaks and the small flat bar comes off of the pin. That wont help much with your 'heat always on' problem but is something easy to check.

Fixing the blend door control will be more complicated so get ready to study up on how to do it. I can only go by what is in the Shop Manuals because I have not done any similar repairs on this particular vehicle and I'm much to tired to get into that right now. Hopefully the blend door will be an easy access easy fix compared other controls and doors in the heating A/C system.

 

[Fixnstuff]

....

Regarding your project with the heater core shutoff - what works against you is that your 87 has full mechanical HVAC doors control, both the 86-down and the 89-up models use vacuum servos and so running a 4-port valve with a vacuum can T-eed into the fresh air door vacuum line is the standard practice, but obviously you can't do that. What you can do is use a 4-port valve that is cable actuated, and hook that up to the recirculating door lever - when the door is closed so is the heater core for max A/C effect. The one thing I don't like about this setup is the same thing I don't like about the vacuum T-ee - sometimes it's nice to have the door closed AND the heat running full blast, if the bypass valve is slaved to the door actuator that's impossible to accomplish.

I could see from the 87 Shop Manuals that this would be complicated. I've used maximum heat many times in very hot weather to help cool an engine, especially when working it climbing a long grade.

Of course most folks have no issue with that cause from the factory the fresh air door is closed only on the "max a/c" setting (well, and "off"), but for trucks like yours where the door is manually controlled you could do the "max heat" trick easily.

My 'fresh air'/recirc air door is controlled by a vacuum motor (described for Eric to check- I hope it's the same on an 88) from a control on the panel (been awhile since I have looked at all of this) unless you meant a different door but I'll look at it all again when I am niot so tired. The diagrams in the manual are a bit confusing and not as clear as they should be and require a lot of study. I saw vacuum lines and control cables but too tired to look now.

This is getting far from Eric's original topic so although it's very interesting to me I'd like to return focus to Eric's situation and coolant filters. I can start a good topic on my plan when I'm ready to dig into it which will probably be after this calendar year ends.

And I wouldn't wast time on a variable coolant flow setup - make it a simple on/off instead, cause when it's fully on you can still vary your vents temperature via the blend door anyways.

Very good advice which will probably prevail but I've always liked technical challenges and solving problems, sometimes (maybe too often) with an obsession (by habit). I HOPE I've learned by now when to quit - when sacrificing further time and energies to arrive at an even better solution is not worth it. Knowing when good enough is good enough and accepting that.

Also a heads-up, I'd highly recommend that you do NOT use the aftermarket replacement diverter valves you can get from the parts store for like $20 or so, they are very hit or miss things as far as quality goes.

I was looking at a very modern OEM 4 port valve and a few diagrams of similar valves. That OEM valve was priced very cheap which in my experience, especially with a difficult to find part like a VRV, means that they don't actually have one to sell but keep such parts listed to bring people to their websites.

At least I know they have good quality OEM valves in newer vehicles that I can find in wrecking yards.

I've appreciated your comments and good advice.

How is Eric going to fix his heater control is what I want to look at and THEN my coolant filter rants - whichever comes up first for me later... after I knock myself in the head right now to go to sleep.

 

[FORDF250HDXLT]

I intend to show good technical reasoning and explanations why not to install the filter in-line with a heater core hose.

this should be interesting.

 

[riotwarrior]

^^^^^ what he said ^^^^^

 

[ericwade381]

Thanks guys the diagram I posted was one I found online. Mine however is reversed at the heater core section that's what was scaring me when I saw it and had me like wow. I just was not sure if the heater core it's self was a in and our design.

 

[FORDF250HDXLT]

Thanks guys the diagram I posted was one I found online. Mine however is reversed at the heater core section that's what was scaring me when I saw it and had me like wow. I just was not sure if the heater core it's self was a in and our design.

the only IN and OUT on the heater core is however you connect it.