cooling system diagram request and question

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?

 

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.

 

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)

 

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

 

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.

 

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.

 

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.




But instead I bought adapters like this:

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:

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.

 

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