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cooling system diagram request and question

Discussion in 'Gen 3 Prius Technical Discussion' started by ThatDudeOrion, May 7, 2019.

  1. ThatDudeOrion

    ThatDudeOrion Member

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    I'm wondering if anyone can provide me a diagram of the engine coolant lines and the flow directions and also answer a quick question regarding the coolant which flows through the exhaust

    Is there always coolant flowing through the exhaust and the valve just dictates how much exhaust flow/heat stays in the heat exchanger OR is there a valve somewhere that takes the exhaust-coolant heat exchanger out of the loop by having the coolant bypass it when the engine gets up to operating temperature?
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Attached is a Repair Manual excerpt on how the exhaust is used to heat coolant, first page has an explanation.

    What's not jumping out at me, is an overall schematic, all the engine coolant system hoses, how they're routed, where they come from, go to. Would be good to have.

    @Ragingfit cobbled some sketches, necessity with his gen 4 engine swap.
     

    Attached Files:

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  3. ThatDudeOrion

    ThatDudeOrion Member

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    This is very cool, thank you!

    I have recently converted my 2011 Prius to the spin-on oil filter and I added a sandwich adapter to start monitoring oil temperature and oil pressure. Oil temperatures so far are quite low in general and take a LONG time to get to the peak which I saw thus far at 190f. I'm contemplating using the coolant/oil heat exchanger "oil cooler" from the Tundra to speed warm-up and better control oil temps and I think the exhaust/coolant heat exchanger might be the perfect place to tap into the cooling system.
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    I've got a vague memory there are two ports on the oil filter housing. They're typically capped, but are maybe for the purpose of an oil cooler, maybe on another Toyota vehicle than Prius??

    Here's website with swap info, I'm guessing you've been there:

    The 2016+ Toyota 2zr Engine oil filter conversion - Armstrong Family Blog

    And the ports (?), a screen grab from the above:

    upload_2019-5-7_10-24-48.png
     
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  5. StarCaller

    StarCaller Senior Member

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    you got some more info on the oil temperature?
    like coolant/oil temperature numbers?
     
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  6. ThatDudeOrion

    ThatDudeOrion Member

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    My daily commute is 2 hours each way of state highways with 55mph limits and stop lights and some interstate of 75+ to keep up and some urban stop and crawl.

    I've only had the gauges hooked up for a couple days, but so far, my coolant will get to 196 within a few miles of my house and the oil temp has maybe cracked 100-120f. it takes a while (~30 mins?) steady state cruise on 55mph highways will net oil temps in the 140-160 range, and the 180-190 oil temps I only saw towards the end of my drive to work where everything is FULLY heat soaked and I'm merging onto an interstate while going up a decent grade and accelerating to keep up with traffic.

    Caveats: ambient air temps in the 50-70f range and I DON'T have the undertray on right now because I'm trying to finish installing a temp probe in the drain plug of the transaxle so that I can verify how closely the transaxle fluid temp is correlated with the MG1 and MG2 temps reported by the Torque app. Also I have a partial obstruction of the lower grill, but I wouldn't call it a grill block (just a led light bar mounted inside the mouth)
     
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  7. ThatDudeOrion

    ThatDudeOrion Member

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    Yes, the Armstrong racing blog was a huge resource for me since they provided the part numbers for the housing, filter, and o-rings. I reused the bolts

    I had actually looked into using those ports you identified to house my oil pressure and temp sensors, but I ran into a little snag with the adapters (reducers?) that I purchased. The ports are M22-1.5 for the curious among us, however the problem I had, and maybe this was unique to the reducers I got, but since they have a 1/8-27 NPT-F hole in the center, they are unsurprisingly hex shaped on the outside and well, whatever size hex they are (lets say 19mm, I can't quite recall at the moment) but it was too small to form a complete seal against the M22 washer and flange on the filter housing and the unfortunate thing is that if the outer hex size of the reducer were any larger, it wouldn't be able to fit due to how the body of the filter housing extends past the plug mounting surface. This is why i opted for the sandwich adapter to house the sensors.

    Those ports may work for an external filter/cooler setup if used with AN fittings or something like that, but a person may likely run into the same issue, depending on how big the hex fittings on the AN lines are. I think a spin-on adapter is probably the best way to go if a user has the desire to use a remote filter or air-oil cooler setup, however, my early anecdata seems to indicate an air-oil cooler would be a huge waste of resources on a prius. which is why I started looking into coolant-oil heat exchangers such as the following found on Toyota Tundra 4.7L V-8

    upload_2019-5-7_14-34-10.png
     
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  8. Mendel Leisk

    Mendel Leisk Senior Member

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    A case of "just because you CAN do something, doesn't mean you have to"? Not sure.
     
  9. ThatDudeOrion

    ThatDudeOrion Member

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    Possibly, but as I mentioned, in my limited testing, I'm seeing that the engine oil is taking a long time to heat up, and it's never really getting to the optimum temperature for efficiency and burning off water vapor and preventing/reducing buildup of acids in the motor oil when the water vapor combines with other combustion byproducts. This is maybe contributing to the high shear figures we see reported in UOA's from the 2zr-fxe.

    My guess is that prius owners who have less rigorous commutes / daily driving habits are never getting their oil as hot as it should be. The oil/coolant heat exchanger would help solve this issue, and for me it would help accelerate cold engine warmup times, reducing emissions etc.etc. which there's not really any downside I can see.

    We have seen Toyota reverse course on the cartridge filters (the use of which made packaging an oil/coolant heat exchanger much more difficult) and now that we're seeing spin on filters back, it wouldn't surprise me at all to see them spec something like the Tundra had on future Prii. I mean, they routed coolant through the exhaust to get it hot faster, they have to know those benefits extend to other fluids like engine and transmission oils. I'm just quite hopeful that I can make the Tundra part fit, it's going to be quite close based on how close my spin on filter is to the engine block.
     
  10. Grit

    Grit Senior Member

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    So it take roughly around hwy driven 2 hrs for oil temp to reach optimum level?
     
  11. ChapmanF

    ChapmanF Senior Member

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    The go-to manual for those kinds of overviews and explanations is the New Car Features manual (more info). The Repair Manual is mostly procedures, and thin on that kind of overview/explanation, assuming you'll have already boned up in the NCF.
     
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  12. ThatDudeOrion

    ThatDudeOrion Member

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    Not exactly, I would say it takes about 30-60 mins of highway driving to get the temps to stabilize around 180. Mine would only go up to 190 if I started to really dip into the ice power to merge uphill or pass somebody going faster than I probably ought to be. Then it pretty quickly returns to 180 ish when you go back to a steady state cruise. At least this was on my way home today around 80f ambient temps. By the time I got off the highway and made my way through town and into my driveway it was down to 140-160 range.
     
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    That sounds very similar to coolant temps I observed, when I was monitoring with ScanGuage. The seem to be neck-and-neck, which seems plausible.
     
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  14. mjoo

    mjoo Senior Member

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    Dude,

    Have you considered something like this?

    Banjo Bolt kit for turbo oil feed

    I'd like to better understand your mounting issue. I have a bypass filter in storage that could go on my Prius some time in the future.
     
    #14 mjoo, May 8, 2019
    Last edited: May 8, 2019
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  15. ThatDudeOrion

    ThatDudeOrion Member

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    OK, so if I had bought adapters like this, it may have worked, with a couple caveats, 1 the OD of the circular part of this fitting isn't too large in diameter so that it interferes with the side of the oil filter housing in these areas highlighted in yellow and 2, parts of the front subframe below the areas in yellow would have interfered with the bodies of the my temp sensors had they been installed in those locations.

    upload_2019-5-8_14-44-41.png
    upload_2019-5-8_14-52-0.png

    But instead I bought adapters like this:
    upload_2019-5-8_14-45-39.png
    and the hex side doesn't form a complete seal around the diameter of the m20 washer,

    In light of all the above, I got a sandwich adapter like this:
    upload_2019-5-8_14-54-56.png
    to use in between the Toyota spin-on filter adapter I retrofitted and the new spin on oil filter, of which I'm using an oversided K&N HP-2009

    so now I have an oil temp sensor and an oil pressure sensor in 2 of the 4 1/8 npt fittings on the adapter. Additional ports could be used to plumb a bypass filter in, if desired.

    My next idea is, because of the low oil temperatures I'm seeing, is to stack the Tundra heat exchanger into the mix to warm up the oil faster and better manage the oil temps.
     

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  16. SFO

    SFO Senior Member

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    Any updates or installed pictures?
     
  17. ChapmanF

    ChapmanF Senior Member

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    I know this is from way early in the thread, but I hadn't seen it before. :)

    There is a separate volume in the set of manuals (more info) called the New Car Features Manual, which is where that kind of overall "here's how it works" information is found.

    The Repair Manual, by and large, is written on the assumption that you've studied that.
     
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  18. ThatDudeOrion

    ThatDudeOrion Member

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    i wish! life got in the way and I lost momentum on this project, but I've been itching to make some progress on it lately
     
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