1997 - fzj80 Cooling System Baseline Question - Water Inlet/Outlet

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Hi all!

Another baselining question but this time, it's with the cooling system.

I've gone through a bunch of threads regarding the updating of the cooling system but I didn't see anything about the water inlet/outlet housing...

QUESTION: If I'm going through everything in the cooling system to replace and update, should I remove/replace the water inlet/outlet? Or should they be pulled and cleaned and just put back on? Or are they one of those, "If it ain't broke, don't fix it" kind of deals?

They aren't leaking but I'm replacing (shown below) the thermo, water pump, fan clutch, etc...All as preventative maintenance. She's been good on these it,es for the seven years I've owned her (and 20k miles) but I don't know what the PO did and didn't do as far as maintenance and now that I CAN do preventative maintenance, I want to. I just need to know if these two forged steel parts can remain or if they should be replaced.

Also, I'm posting my spreadsheet for my coolant baseline...if anything is missing, please let me know!

Green = Purchased
Yellow = On Deck to Purchase



Thanks in advance!

Coolant.PNG
 

Njck22

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aluminum outlet and inlet do not need replacing unless they are deeply pitted or leaking. I'd recommend doing all the firewall heater hoses, the throttle body coolant hoses(3) and water bypass outlet pipe orings (3). Your pesky heater hose part number is wrong. I recommend doing the bypass but if you're a glutton for punishment, that part you need is 9955630100 and clamps. Go ahead and get the outlet bypass hose too.
 
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aluminum outlet and inlet do not need replacing unless they are deeply pitted or leaking. I'd recommend doing all the firewall heater hoses, the throttle body coolant hoses(3) and water bypass outlet pipe orings (3). Your pesky heater hose part number is wrong. I recommend doing the bypass but if you're a glutton for punishment, that part you need is 9955630100 and clamps. Go ahead and get the outlet bypass hose too.
Oh, the inlet/outlet are aluminum? Good to know, and thanks! They aren't leaking so I'll probably just leave them "as is" for now.

Definitely planning on the firewall hoses; I'll update my spreadsheet with those. I wasn't aware of the throttle body coolant, so I'll add those as well as the water bypass pipe openings.

Thanks for the PHH part number correction...I've read a few threads about bypassing this and I found this one seems to be pretty detailed.


Thanks for replying and giving some additional insight/help! Anything else you'd recommend?
 
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FWIW, that head coolant bypass hose (aka PHH) only starts to leak after 30 years. Pretty good life expectancy, if you ask me. Unless you plan to drive it for another 40 years, just put back what Toyota installed at the factory. You'll be fine. If you do plan to drive it another 30+ years, buy two hoses and clamps for both. You can re-engineer the coolant system if you want, but you should be really sure you know what you're doing. Toyota didn't design this system over lunch on a napkin.

It's easiest to get the clamp and hose on with the head off, but if that's not an option, buy a new clamp, leave the retaining clip on it and slide it over the nipple on the head, after you install the hose. A dab of Vaseline on the inside of the hose helps, too (the clamp/bead will keep it in place). The retaining clips open the clamps farther than pliers do, and they slide over the bead easily with the clips in place. You can then just pull the clips off with a pair of pliers.

Same goes for the lower end of the throttle body bypass hose. If you think the rear hose is hard to get to, install the throttle body hose on the head first. After that, the rear hose will seem like nothing.
 
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FWIW, that head coolant bypass hose (aka PHH) only starts to leak after 30 years. Pretty good life expectancy, if you ask me. Unless you plan to drive it for another 40 years, just put back what Toyota installed at the factory. You'll be fine. If you do plan to drive it another 30+ years, buy two hoses and clamps for both. You can re-engineer the coolant system if you want, but you should be really sure you know what you're doing. Toyota didn't design this system over lunch on a napkin.

It's easiest to get the clamp and hose on with the head off, but if that's not an option, buy a new clamp, leave the retaining clip on it and slide it over the nipple on the head, after you install the hose. A dab of Vaseline on the inside of the hose helps, too (the clamp/bead will keep it in place). The retaining clips open the clamps farther than pliers do, and they slide over the bead easily with the clips in place. You can then just pull the clips off with a pair of pliers.

Same goes for the lower end of the throttle body bypass hose. If you think the rear hose is hard to get to, install the throttle body hose on the head first. After that, the rear hose will seem like nothing.
Thanks for all of that.

Pulling the PHH will definitely be accomplished while the engine is still in the bay and the head is still attached...so, I'm assuming there will be a lot of cursing, prying, throwing things, and a general temper tantrum thrown...but it'll be worth it, from what I've read.

I'll try to get a pic of it posted sometime this weekend for inspection. My '97 has 220,xxx miles on it and from what I have gathered, a lot of the hoses and clamps don't look OEM (topside of the engine bay), particularly around the Heater Control Valve. From what a couple other members noted (I think you might have also), the clamps around the HCV are definitely NOT OEM...but again, I have no idea what the PO did and didn't do to her...so, in my opinion, it's best to just replace all the hoses.

When I post the PHH image, if the general consensus is that it's "fine" then I'll leave it be for the time being.

As of this note, older brother has a '97 also (his is green) and he has about 375K miles and hasn't had an issue with his, although, since discussing the Heater Control valve, he commented that it is "yellowing" so he ordered an OEM replacement.

Engine Full Front.JPG


Engine1.JPG


Engine3.JPG


Engine4.JPG
 
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I'd replace the two lower head connected hoses, unless you know they have been replaced with good hose (Toyota or otherwise), and clamps, recently. Especially important is the rear bypass hose, because when it leaks, it leaks onto the junction connector from the engine harness to the transmission harness, and you'll lose the PRNDL2 tree lights and the backup lights. And you do not want to service that connector with the head in place. Ask me how I know.

Also, pull the drop hardline to the rear bypass hose, put the hoses on that (both ends), and then put the other end of the hose on the hardline. THEN, connect the upper end and bolt the hardline onto the head.
 
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I'd replace the two lower head connected hoses, unless you know they have been replaced with good hose (Toyota or otherwise), and clamps, recently. Especially important is the rear bypass hose, because when it leaks, it leaks onto the junction connector from the engine harness to the transmission harness, and you'll lose the PRNDL2 tree lights and the backup lights. And you do not want to service that connector with the head in place. Ask me how I know.
So very noted, thanks.

And this is why the ih8mud site (and its users) is my bible for this rig :)
 
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IMHO, if I were you I would at least get eyes on the PHH and see if it's swollen. I'd also try to get my hand on it and palpitate it a bit to see if it feels hard as a rock, crumbles in your hand, etc. And then respond accordingly with either no action or replacing it.
Also, I think it is important to consider your use case in deciding what to change out on your rig, and whether you work on it yourself or pay someone else to do so. For me, I do a lot of semi-remote solo trips in the desert and mountains. My rig has to be as reliable as possible, period. Also, I work on it myself. So, as PM, I have replaced things like the starter, radiator, all the hoses and clamps in the cooling system, thermostat, electrical relays, fusible link, water pump, etc.
There are a lot of posts on Mud about baselining, but I think one should consider use and budget, and worst case scenario for a failure when deciding the proper scope of baselining For You. If it's an around town rig and you have another car or two, that's a lot different than if it's a rig you take out on remote trips with your two kids and a dog. Just my two cents.
Good luck and the tips above are all good ones, too.
 
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IMHO, if I were you I would at least get eyes on the PHH and see if it's swollen. I'd also try to get my hand on it and palpitate it a bit to see if it feels hard as a rock, crumbles in your hand, etc. And then respond accordingly with either no action or replacing it.
Also, I think it is important to consider your use case in deciding what to change out on your rig, and whether you work on it yourself or pay someone else to do so. For me, I do a lot of semi-remote solo trips in the desert and mountains. My rig has to be as reliable as possible, period. Also, I work on it myself. So, as PM, I have replaced things like the starter, radiator, all the hoses and clamps in the cooling system, thermostat, electrical relays, fusible link, water pump, etc.
There are a lot of posts on Mud about baselining, but I think one should consider use and budget, and worst case scenario for a failure when deciding the proper scope of baselining For You. If it's an around town rig and you have another car or two, that's a lot different than if it's a rig you take out on remote trips with your two kids and a dog. Just my two cents.
Good luck and the tips above are all good ones, too.
Thanks for the input and advice!

She's not my DD...that's reserved for the Avalon Limited primarily for comfort and way better MPG (currently about 30 mpg mixed)...I'm planning on running some old trails my dad and the FJ40 club he was a part of in the early 80's cut up here in the PNW, and camping. I'm not really interested in hard rock crawling...not because it isn't fun, but things break more easily. Plus, and nothing against those who like to scale up tall red rock walls, I'd just rather go around than screw up and roll down, you know? So, camping, overlanding, some moderate trail running, exploring (some remote areas in the PNW for sure), etc. I've known my entire life that Land Cruisers are over built and about THE MOST capable rigs out there, so I'm not worried.

Currently, I have either ordered or have sitting in a box waiting to be updated:
  • New Tires (Copper Adventurer 265/70r16)
  • Drive belts
  • Spark Plugs / Wires
  • Cap / Rotor / Dizzy-O
  • Heater Control Valve
  • Fan Clutch
  • Water Pump (With gasket & stud)
  • Thermostat (With Gasket)

All hoses are all being purchased next week sometime.

The hope is she'll be mechanically baselined by the end of this summer; I'll then throw in the Kenwood double din and speakers another Cruiser friend gifted me when he updated his sound system and make several small trips...and next summer I'll have the 2"-2.5 inch lift installed, 285 tires thrown on her, and then front/rear bumpers with rear swing out.

That's the hope, at least.


I'm not married and I don't have any kids, and my HOA (until very recently...like three months ago) didn't permit dogs in the community...so aside from saving for a down payment on another place, everything outside of bills and life is dumped into savings.
 

Njck22

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FWIW, that head coolant bypass hose (aka PHH) only starts to leak after 30 years. Pretty good life expectancy, if you ask me. Unless you plan to drive it for another 40 years, just put back what Toyota installed at the factory. You'll be fine. If you do plan to drive it another 30+ years, buy two hoses and clamps for both. You can re-engineer the coolant system if you want, but you should be really sure you know what you're doing. Toyota didn't design this system over lunch on a napkin.
I totally agree that toyota is not naive when it comes to designing these things, and 30 years of life is great for a heater hose. But this is a mass produced vehicle. On an assembly line, the engine goes in as one piece. there is no time to be fooling around with routing a heater hose around the brake booster. So they routed it straight up, with a hardline. These parts are installed with the engine off the vehicle, very easy and the only connection that is made once the engine is the vehicle is the connection from the phh hardline to firewall heater valve. So while not the "OEM" way, the bypass routing simply wasn't a possibility for toyota, even if it is optimal, which in my opinion is.
 
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I totally agree that toyota is not naive when it comes to designing these things, and 30 years of life is great for a heater hose. But this is a mass produced vehicle. On an assembly line, the engine goes in as one piece. there is no time to be fooling around with routing a heater hose around the brake booster. So they routed it straight up, with a hardline. These parts are installed with the engine off the vehicle, very easy and the only connection that is made once the engine is the vehicle is the connection from the phh hardline to firewall heater valve. So while not the "OEM" way, the bypass routing simply wasn't a possibility for toyota, even if it is optimal, which in my opinion is.
So, it's in everyone's opinion to change/swap to the PHH kit, correct? Easier and more efficient set up AND easier to work on after the fact?
 
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So, it's in everyone's opinion to change/swap to the PHH kit, correct? Easier and more efficient set up AND easier to work on after the fact?
You do you.

I chose to pull the pipe, remove and replace the hose on the PHH, then reinstall original pipe with new section of Toyota hose. I did NOT use Gates Green Stripe as many do because I didn't like the fit.

It can be done with a standard ratcheting combination wrench, 12mm, with angled head on ratcheting end, from the top side on the two bolts with the valve cover still installed, but with the heater valve and all heater hoses removed.

Jack up and remove LF tire and inner fender flaps for better access from below.
 
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^x2. Same here. Opinions vary.

I will say, just for the sake of nearly repeating myself, if you choose to do this with the head on, and without draining the coolant, cover the engine/transmission harness junction connectors BEFORE you open the coolant system. If you don't, you'll wish you had.

Also, now is the time to install the new, and improved, block drain:
1658428645496.png
 

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