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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