mt_goat

You can get one at any Toyota dealer if you tell them the part #. This dealer sells them for $54.72 https://www.1sttoyotaparts.com/partscat.html

suprathepeg

SO what is the part number?

mt_goat

Edit: The new number is PTR04-35050 and they are $54.72 here:
https://www.1sttoyotaparts.com/partscat.html

TNRabbit

mt_goat: What exactly are you considering to be a high operating temperature? If the t-stat opens at 165, doesn't that make your engine run less efficiently? I saw you had up to @ 205 degrees here in your post somewhere. Most new engines operate most efficiently above 185 degrees, & coolant doesn't boil until well over 212, so what's the problem?? what is supposed to be the max operating temp of these engines?

mt_goat

See post #454. https://www.yotatech.com/forums/show...&postcount=454

As far as the max that's a good question, whatever temp the coolant starts to boil at the head is the limit.

mikewic

have you by chance had the a/f ratios looked at? it sounds like it could be running a bit lean at the upper rpm ranges and under heavier loads. maybe some tuning? I know when we work on performance stuff, we have to watch things really carefully for leaning, one sure way is water temps. if it starts to get pretty hot when under load, chances are it's running a bit lean.

mt_goat

Yep, I'm constantly monitoring with this stand alone wide-band A/F gauge:

See post #454 https://www.yotatech.com/forums/show...&postcount=454

suprathepeg

The t-stat may open @ 165 but is pegged @ about 180 so that is about where you want it depending on how hot the engine runs. I find that once my engine temps excede 210 the ECU starts to really retard the timing and the engine starts to run like poop. Mine is a 3.0 but I find I get best performance when I'm reading 180-190*.

mt_goat

To make it easier to keep an eye on the temps I placed a temp probe in my upper radiator hose yesterday, it's screwed into a section of steel pipe 1.5" diameter, drilled, tapped to 1/4" NPT, and sealed with water pump RTV:








Also installed the TRD 160 t-stat, but before I put it in, I did one more test this time comparing the TRD (left side) with what was in before, the URD (Napa 170 deg):

Here at about 180 deg, the TRD 160 (left) is well on the way to opening, while the URD (Napa 170) is just started to make a crack


Here at about 210 deg the TRD is still open more than the URD:


Cooling back down to 180, the URD (Napa 170) is just barely open and the TRD 160 still has a wide openning.


The URD (Napa 170) does have a 0.11" bigger diameter opening if the valve was open all the way but at no time during my test to boiling (212 deg) was it opened as far as the TRD 160.

TNRabbit

Your temp probe is a great idea! How's it working?

mt_goat

Thanks Rabbit, it works pretty good. The initial warm-up before the t-stat opens its reading about 25 degrees lower than the OBDII temp probe, which is understandable since there isn't any flow to the radiator through the upper hose. Once the t-stat opens it's reading 4-8 degrees higher than the OBDII readout.

My fan started kicking on when the gauge reads 182 and the OBDII reads 174 and it held steady there just idling in the driveway. I manually switched off the fan to let it get hotter and at 190 on the gauge the OBDII was at 183, and at 200 the OBDII was at 196. That's as hot as I let it get and switched the fan back on and it quickly settled to 180 (gauge)/172 (OBDII) with the fan barely running. I haven't driven it yet.

I'm hoping to do a little test drive later after I get all the air bled out.

shoes138

DAMn MT goat, i just got done looking at your photo album in webshots, And damn you got alot of skills. Your truck looks like it all Professionally done! you did a great job! i hope my engine will be the same! but keep up the great work and pics! and i wish i had a drill press man those things are sweet!

mt_goat

Thanks Mr Shoes, I guess I picked up a few tricks and tools with 50 years in the rear view.

Cooling Update:

The TRD 160 t-stat test went pretty good yesterday, it helped some anyway. The temps were about 5 degrees cooler on the high-end and (as expected) 10 or more degrees cooler on the low-side at idle. The ambient temp was 81 deg (vs 83 for the URD 170 test) but everything else was the same (road, distance, AC on, CC set on 75 miles per hour). The max temp was 212 at the top of one long hill (slight grade but the boost gets going some) and generally it stayed in the 200-205 range once it got good and hot, which seems to take about 8-10 miles at 75 miles per hour.

So bottom line : I'm going to keep the TRD 160 in place (at least for the summer, we'll see how it is in the winter), but that's still not cool enough for hotter weather and much longer and steeper mountains to climb, at least not with water based coolant in the system.

So on to plan B, here's the options I'm considering:

Plan B3: Bypass the radiator ATF cooler competely (maybe Brian's original theory was right) that autos can't run e-fans as well as manuals because of the extra heat dumped into the radiator from the ATF.

Plan B4: Remove one of the ATF coolers in front of the radiator to increase air flow and decrease heat (in front of the radiator). Replace it with my old tranny cooler which is currently being used as a powersteering cooler and probably not needed anyway, click on pic:


Plan B5: Convert to Evan's waterless coolant (see post # 468 here: https://www.yotatech.com/forums/show...&postcount=468) While this will likely not lower the engine temps at all, in fact they may go up just a little, it will give a nice level of insurance that even if I do run too hot at times the coolant will not boil in the head and cause hot spots that can do all kinds of serious damage (cracked or warped heads, detonation, blown head gaskets, to name a few).

Plan B6: Replace my $120 cheapie aftermarket 3 core brass/copper radiator with an expensive custom aluminum radiator like designed by Downey for V8 conversions. After talking to the radiator builder again (http://www.alumrad.com/) I'm starting to understand radiator design better. Appearantly one large core (like 1 3/8") transfers heat better than a multiple small cores (less than 1/2") because the air can get through them better. I know the factory Taco radiator is aluminum and has one large core and the Taco guys over on TTORA swear by them and seem to have problems when they replace them with anything else but the factory radiator. I may be even be able to fit in a 2 core aluminum where each core is 1" width for an over all thickness of 2.5"

Plan B7: Replace the Taurus fan with the stock mechanical fan, may try this before Plan B6.

Plan B8: Remove the other ATF cooler in front of the radiator and relocate somewhere not obstructing the radiator air flow.

Plan B9: Last resort, remove the winch and/or TJM bumper and replace with a tube bumper for better air flow.

I'm also going to remove the weather stripping at the rear edge of the hood to see if it might help air flow under the hood. I could also raise the rear of the hood a little with spacers for test run to see if a cowl hood scoop may help.

Any thoughts?

suprathepeg

I would say your next move should be the aluminum rad. I'll bet that is your best bet. I just made a spacer for my engine so now I can run the 3.4 stat I'll let you know how that goes.

mt_goat

Yeah that's probably the "big bang" hopeful fix, but I have to try the cheap fixes first. Actually I sort of already ordered an aluminum radiator from Radiator.com but haven't paid for it yet since they have to make it first (2-4 weeks) and they couldn't even quote a price until then.

mudbutt

I just installed an aluminum core, plastic tanks radiator (customers 4runner not mine). It was made in china but sold through Modine (lifetime warranty), i was able to get it through my local shop "spikes radiatior". The core was just one big core, but it was about 3 conventional cores wide.

My truck is running at 198 most of the time (conventional 3 row). I just ordered the t-stat you installed to cool me down a little more. The part number changed again to ptr05-..... I'll insert this tomorrow I forgot the rest of the number. My cooling fan (stock mechanical) kicks on at longer idle times (A/C on) but that is about it. I have a giant wind break warn rockcrawler bumper and winch. I'll let you know my upgraded t-stat temps later this week.

mt_goat

Hey thanks Mud, let me know how that works out. I suspect the one I ordered from Radiator.com will be a plastic tank model too but as long as they have a lifetime warranty you can get new ones for free.

Yeah the TRD 160 deg t-stat part number did change again but the computer links them. The new # on my bill was PTR04-35050 and it was $54.72 from Bob Bridge Toyota here: https://www.1sttoyotaparts.com/partscat.html

It does come with a new gasket but it's hidden inside the bottom of the box so don't throw it away by mistake.

BTW I must say again the service is excellent at Bob Bridge for parts. They sent a Fed-ex truck to my door to pick-up the wrong part they had shipping by mistake and they shipped the correct part on their dime (no shipping charge). I've ordered lot of parts from them and they always had the best prices and that was the first time I got a wrong part so I forgive, everyone will make a mistake sometime. Here was one of my previous experiences of them too: https://www.yotatech.com/forums/show...ght=Bob+Bridge

toy power

man, thats good that you have gotten it down a few degrees. i do still think that there is just something seriously lacking when your temps are 40 to 50 degrees past the thermostats rating. do you have any idea when the aluminum radiator will be done? also, do you have the fan and clutch from the 3.4? I was all about electric fans for a long time, but you cannot beat one for pulling massive cfm for low bucks. I place my bet on that radiator not cutting it..

mt_goat

Yeah, you may be right. The aluminum radiator I thought I had ordered from radiator.com they now say they can't get one.

Yes, I still have the 3.4 fan and clutch as well as the 3.0 fan and clutch, and I may just throw one on and try it.

Are you saying you can't beat the mechanical fan for massive cfm?

toy power

Now they say that they can't get one? Sounds like they may not have been the place to get one anyway huh. I am sure there are other vendors who can get you one or make you one and actually give you a price, and even the radiator for that matter. As for the fan, I meant that it is more cost effective to use a mechanical one in a situation requiring a lot of air movement. I had a broken fan clutch on a 302 ford, and thought I may as well replace it with electric fans. It was not suitable for SC heat and humidity with ac on.