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The pump cannot cavitate air if none is present. The pump just keeps the coolant moving so it can circulate through all parts of the cooling system. The volume of coolant that passes through the radiator and heater core dissipates enough heat for all the coolant when it mixes upon return to the pump (heat is equalized/transfered from different parts of the system when it mixes at the pump). Tim
I think air is likely due to steam pockets forming near hot spots in the head. The van is not renowned for its flawless cooling system.
1. Limited Air flow
2. Low pressure radiator cap from the factory. = coolant prone to boiling
3. A thermostat on the inlet side of the block
Here is my bible on cooling.
http://www.pirate4x4.com/tech/billavista/Cooling/
For a long time I have wanted to install a surge tank on the van.
Less than a decade after the van was produced; pressurized coolant bottles and 20 lb radiator caps became standard equipment on most cars.
Would there be a negative effect if I plumb the HOD to the Radiator vent tube? Or a surge tank installed inline with the Heater Core supply hose?
This puts it closer to the coolant leaving the block and a means for air to escape.
Looking at that pirate 4x4 page made me realize I'm pretty old school with my knowledge on cooling systems. Perhaps if some modern knowledge is applied to our "old school" vans, some worthwhile improvements could be made (definitely room for improvement). I'm currently blessed with vans that do not give me any grief in this area, but I know our cooling systems can be problematic. If you happen upon that "magic mod" that cures these issues please share with the rest of us :thmbup:. Tim
#1 mod so far is 19 lb radiator cap. By mishomoto. (sorry no part number). I'll make a new thread with my cooling mods.
On a hot day, when the thermostat runs up to 3/4, I do not loose any coolant.
With the stock cap. A slight overheat purges coolant and even if you idle to cool down, the system is still likely to be low. Any loose hose or slight leak in even the heater core will suck in air instead of coolant.
I believe so.
Keep in mind that coronan has a new aluminum radiator. Putting a high pressure cap on an aging OE radiator and/or marginal hoses may end in disaster. Tim
Thanks Tim. I didn't know he got a new aluminum radiator, nice. I realized after I wrote that it was not responsible if someone(or me) read this thread in passing and decided to up the pressure without knowing what they were doing.:?:
I was just reading that pirate4x4 cooling system thread and it's long and very informative.
Coronan- I look forward to your cooling system thread and addition of a surge tank.
A stock 13 psi cap is fine for the temperatures the van is designed to run. It's true that more pressure will reduce and/or prevent boil overs, but a 13 psi cap will not allow boil-over unless temperatures exceed design limitations of the van. If allowed to get hot enough for that to occur more stress on things (particularly your head gasket) is the end result. True, a higher pressure cap will delay (and may even prevent) boil-over, but the temperatures reached before that point are much more damaging. Although only another 6 psi, I would advise against that cap. If you do it anyhow, then you should at least have an accurate temperature gauge that reads in degrees. A stock van is typically fine up to ~220° F. If it's running hotter than that, then you're pushing the limits. Excessive wear and/or damage to head gasket, pistons, cylinder walls, and rings will start to occur at temperatures above 230° F. The ideal operating temperature of the 3y/4y falls between 185° F - 210° F. If yours is consistently running above that, then there's something else going on that needs to be addressed. Tim
Thanks Tim-won't be upping pressure on this van. I will be going for an extra radiator(heater core mod) like you did to help with cooling when the a/c is on in the summer.
in the pirate 4x4 cooling thread they don't list an extra radiator in their ten commandments but i think it's a viable option for us.
Some facts to consider: @ 0 psi (no cap) a 50/50 antifreeze/water mix boils @ 226° F. @ 13 psi, it will boil @ 261° F. @ 19 psi, it will boil @273° F.
When you shut-off the engine the coolant circulation stops, so engine temps will temporarily increase (I'm guessing around 30°). Other than possible heat soak issues this is of little concern because the engine is stopped (no wear on moving parts). However, if your engine operating temp is >230°, it will likely boil-over after shut-down and you'll lose some coolant (at least with a 13 psi cap). This is the only scenario where the 19 psi cap could help, but it would only reduce and/or eliminate coolant loss. If your van is running hotter than 220° F, then you're better off finding and solving the root cause rather than using a higher pressure cap (band-aid). Just my 2¢. Tim
Alright guys... I have a further question to ask on this Hose of Death thread.
I sent in my head to get rebuilt, and need to put the Hose of Death 4 bolt plate back on the head.
Can anyone help with what kind of gasket maker this plate requires?
Thank you!
Hugh
There is actually a gasket that goes here. It's Toyota part #11182-71010. Although not required, I'll usually use a very thin layer of FIPG (Form-In-Place Gasket) on both sides of the Toyota gasket. If you need the plate/nipple, I believe it's still available for 2wd vans and 5-speed 4wd vans. That is Toyota part #11181-73010. If you have a 4wd auto, sadly that plate/nipple is NLA. You'd need to resort to something like what trestlehed did in this post: http://www.toyotavantech.com/forum/s...5321#post25321. Tim
Tim you are incredible! Thank you! I would have never know, the plate was stuck on with some sort of white gasket maker before... I just ordered the gasket so I'll be good to go now!Quote:
Originally Posted by timsrv
-Hugh
im in the process of planning out a heater delete to make things easier/more simple and have less chance of something leaking down the road.
am i able to make a block off plate for the rear hose of death, and block off the line going to the front/rear heater hose T, and still have the coolant circulating through the engine via upper/lower rad hoses?? im aware i would be bypassing the throttle body warmer but i wont be driving it in cold winters so thats not too much of a concern...is there anything else im bypassing that will cause troubles? if there is no coolant going to either front or rear heater hoses, will i have to worry about capping the line here: Attachment 5134
or will be there be no coolant going to that line anymore anyways after the rear plate has been blocked off?
thanks for all the help, i think i know what i need to do for the most part but im still a bit unsure what all happens with the coolant bypass hoses, and how much theyre needed
I'm not sure what you're using the van for, but not having a working heater doesn't sound like much fun to me. To each his own I guess. If you really don't want it, there will be 3 places to block off and they're all on the head.
There's the "hose of death" port on the back of the head
http://i8.photobucket.com/albums/a23...pssumw04ue.jpg
The heater hose output port on the front of the head
http://i8.photobucket.com/albums/a23...pswmjyxsk0.jpg
And the heater hose return port on the side of the head (right behind the radiator return port)
http://i8.photobucket.com/albums/a23...psftuaw28t.jpg
That last one would be a PITA to cap off with the engine installed/assembled. An alternate way for that could be to put a hose plug on the metal tube where it comes out the D/S back of the engine. If you do it that way, then you'll also need to get the bypass return line that's also part of that metal tube assy.
Frankly, I'd rather replace hoses, then you'd have heat and not need to mess with it (at least the hoses) for another ~30 years (but that's just me). Tim
Thank you for your response! that last picture was what i needed to see!
The reason for wanting to remove the "water bypass" hoses is that many of the nipples that connect to the heater hose (eg. the little metal tubes coming off of the throttle body) have rusted completely off and are no longer really usable....rather than just bypassing all of this with more heater hose and having pointless hoses going throughout the engine that no longer are serving a purpose....i figured it would be easier in the long run to bypass all of this and just have coolant flowing through the engine. I wouldnt complain about still keeping the heaters, but i didnt think that would be possible with removing the throttle body heater hose/idle air control valve/hose of death/everything else that runs around the intake area.
Thanks, andrew
I'm in Van purgatory right now with the Hose By-pass Pipe No.2 on my 1984. The steel coolant pipes are riddled with cracks along rusty striations that run their entire length. I'm wondering if anyone can sell me a new by-pass pipe!? Its pipe number 16278 on the diagram below.
http://parts.germaintoyotaofnaples.c...ze/MA6928D.jpg
...And thank you for creating this wonderful forum site Tim (and co.)! It's a breath of air after feeling like I was underwater for so long.
Quote:
Originally Posted by Surf5557
That one is likely still available from Toyota. It's part #16278-73011 and sells for around $60 (MSRP), or you can purchase from the site I linked to (click on the part number above), and pay $43 (then pay the $17 you saved in shipping). Tim
Does anyone know the correct order of operations for installing the upper manifold and throttle body? Last time I struggled for hours trying to line up the most accessible bolt that holds the by-pass bracket to the manifold, but I gave up on the second bolt that was further towards the "Hose from hell." Is it somehow easier to assemble these parts with the by-pass pipe already mounted?
Also, I find that the length of my hoses is causing issues. Nowhere in my 1984 Factory Manual does it list instructions for this. I'd love to just bypass the by-pass!
I vaguely remember dealing with that years ago before cutting the access hole (as pictured earlier in this thread). Hasn't been an issue since. Did you cut an access hole?
If you're planning to use the van in cold temperatures (below freezing), I wouldn't disable the bypass. Doing so would prevent the air valve from working and would allow freeze-ups of the throttle body. Tim
Edit: I believe I leave that pipe assy bolted to the manifold, then cut both the bypass hoses (HOD 1 & 2). The vacuum lines are not that hard to pull off. After the manifold is out of the way, it's easy to clean-up/remove the left-over parts of hoses. Tim
Thanks Tim!
The second go around to correct the leaking bypass pipe I brazed the holes with an oxyacetylene torch and brass, then I bolted it onto the throttle body/manifold, and after that I installed the manifold. The last thing I ended up doing was connect the hoses (without the access hole) and everything is sealed up tight now for 2 weeks.
I'm convinced I fixed the leak this time, although I'm a little embarrassed that I did use some alumiseal in the coolant and it did nothing but congest my cooling system. Whoops
In the last picture you have included a peek of the vacuum lines that go into the valve on the power steering pump. How does one correctly install those hoses when the valve can be under/over torqued and the orientation of the ports reversed? Is there indication for correct orientation on the pump valve?Quote:
Originally Posted by timsrv
It doesn't matter if they're reversed. It's just an on/off valve so it doesn't matter which hose goes where.Quote:
Originally Posted by Surf5557
the pre-formed hoses on the underside of the intake (part numbers in purple) are all NLA.
Attachment 5468
I have some hose the same size but it kinks when I try to bend it at that angle. I was able to replace the one small straight piece obviously, but the bent pieces kink pretty bad.
is there a way to form it to the proper shape? or maybe use a different type of hose material thats more flexible?
That really sucks............I was wondering when that was going to happen. Those are all vacuum hoses with ~1/2" ID (to direct air through the Auxiliary Air Valve). The only thing that comes to mind is to find some 1/2" ID formed heater hose with tight bends, then cut parts out of it to match what you need. When I get in a spot like that I ask the guys at my local Napa to let me look through their inventory. There's also some weird shapes and bends available at the Dorman HELP! rack.
Then there's brass nipple elbows pushed onto straight hose. Another option is Unicoils. Gates makes devices called "Unicoils" that you put over straight hoses. You get one that fits the OD of the hose, then you can bend sharply and it prevents kinking. They work, but I'm not crazy about them as they make the hoses heavy and clunky. As these vans get older and parts get harder to find, I suspect there will be a lot more of this type thing we're forced to do to keep them on the road. Good luck. Tim
That really sucks as I was getting ready to rebuild a spare engine and replace all that stuff. I went through this when I did my head gasket 5 years ago. I tried my best to avoid the dealer but ran in to problem after problem with aftermarket hoses. The issue was the diameter. They actually are not 1/2 inch but 12 mm which requires a clamp to seal and is still not ideal. From what I remember there was not enough room on some of the air valve connections to install a clamp. I had the same issue with coolant hoses and the local industrial hose supplier told me this was common on Toyota, Mercedes, and a few others that chose to use metric sizes. The solution was to either stretch on the next size down or clamp down the next size up. I ordered all that was available form the dealer and compromised on the rest. I used a unicoil for the small angled hoses at the rear heater core as they were NLA at that time but like Tim said it makes for a bulky hose and may not fit for the air valve application. Two years ago when I tried to find a unicoil for my Subaru most parts store counter persons looked at me like I was a moron and said," A uni-what?". The guy that finally knew what I was talking about said they quit making them but I've still seen them online just not on the local parts store counter.
And this is why I had to spend eight hours on my back on a cold cement floor (and cussing almost the entire time) to replace a leaking HOD not all that long after the head job (by someone else). There's no substitute for OEM hose, especially in any hard-to-access locations!Quote:
Originally Posted by originalkwyjibo
Gwen
I was incorrect on the size. Factory is 14mm not 12mm. Hope I didn't cause anyone confusion.Quote:
Originally Posted by originalkwyjibo
Just another Hose o' Death access panel job, and huge thanks to the detailed original post and all the help that was posted after. I'm replacing the hose with the only thing the local CarQuest auto store had that will fit, SAE 30R7 fuel line hose. It's rated to 50 PSI working, 250 psi burst, 275 degrees F, and is nitrile-lined. The silicone heater hose sounds better, but a hose in the hand...
Attachment 5554
Attachment 5555
Good luck man. I nearly got burned by the previous owner cheaping out and using 50 psi fuel hose rather than proper heater hose for a hose of death replacement. It worked for a couple of years but split in half at literally the most inopportune time.
I'm sure you could rock it for a while but I'd hope you get some proper hose for it. It'll be a quick replacement since you've already done all the leg work.
It's a valid point, and I'm going to pick up the Toyota 99556-10200 (or 99556-10300, as Tim recommended, long enough to make two replacements) as soon as possible. The original seems too have lasted 29+ years, that's good enough for me. Thanks for reinforcing the urge to get the right part.Quote:
Originally Posted by AD2101
I'll be doing this change out soon and post another video of the process once I get into it. Thanks so much TIM for all the reference points and education. It's definitely invaluable!
Looking forward to it. Ramjetalpha1Quote:
Originally Posted by armorrell
It would appear that it is prudent for a new owner who is positive that nothing has been done in 15 years to a van to flush, then replace all water hoses, and the thermostat? And that the OEM hoses are worth the premium. Time to get a parts list together. Any particular antifreeze? Will the antifreeze sold for Asian cars work? Or is that for aluminum engines?
For those that need preformed tight bend vacuum hoses that are NLA 90 degree plastic angles are available from a variety of sources.
https://www.google.com/search?client...30.JwLHLHVeh0c
Hydroponic supply stores might be a source. I think Granger or a heating supply Jobber. Some heating systems are vacuum controlled. A brake tubing bender might let you do the angle in steel.
The other day after driving the van on some morning errands I noticed some smoke coming out from underneath the driver side of the van, I opened the door and could hear a drip and burn off with smoke, because of where it was located I thought for sure it was the Hose of Death!!
Contacted my MasterTech and informed him of what was happening and the following day Sunday afternoon I drove it over to his house for a quick diagnosis. He jacked up the van and rolled under with the creeper for inspection and found not only that the Heater circulation molded hose was dripping but the Hose Of Death had developed elephantitis (fully expanded) unfortunately I couldn’t get a picture of that from laying on the creeper.
Thank you Tim for documenting this thread, I sent him the link for review as an easier option for the repair and he loved it.
Leaking Heater Circulation Molded Hose/Repaired with molded hose to route away from the manifold.
https://i.imgur.com/JAoMMuz.jpg
https://i.imgur.com/dqjhCKm.jpg
https://i.imgur.com/BMrwTtE.jpg
https://i.imgur.com/4WH3eDn.jpg
Hose of Death ready to blow
https://i.imgur.com/sZBCgJQ.jpg
https://i.imgur.com/4m8PPUe.jpg
Cut access hole and replace with the Gates Heater Hose, new clamps, heater foil wrap and seal back up
https://i.imgur.com/nQuIslI.jpg
https://i.imgur.com/umARJJc.jpg
https://i.imgur.com/HeM0IC5.jpg
Thank you Tim
JDM
Has malleable copper tubing been tried? this seems to be a cheap and easy to bend tubing https://www.youtube.com/watch?v=oWP_zEKLvyc
I haven't tried copper tubing for the HoD, but this is a nice method, thanks for the link!