maybe a heater hose inlet and outlet incorrectly connected. i have never personally wrenched on a 3.4, so i couldn't be specific. i just remember a friend of mine with a K5 had connected a heater hose off his water pump so that it bypassed his thermostat, and the truck took about fifteen minutes to get to operating temp. figured the opposite may be possible as well.

 

I was talking to a radiator guy last week that makes custom aluminum radiators for Downey. As I was describing my problem he says do you have a winch? I said yes, how'd you know? He's seen a lot of problems lately from those new big Warn winches with the air compressor on top of them. He says at highway speeds the air hits the front end and with all the turbulance going on the air flow ends up just going over the hood. He started describing how to make an air foil to funnel air into the radiator when I told him I'd already done that.

 

I suspect this is exactly what's happening, but with your bumper rather than the winch alone.

Basically, I see two possible solutions:

1) Cut holes in the bumper to allow some flow through it. That or go tube bumper.

2) Remote radiator (obviously not the preferred option).

 

Well after looking at the bumper and feeling around with my hands I don't really see where I could cut any material out that would make much of a difference. The winch pretty much takes up all the bumper space in front of the radiator. I did notice the trans coolers are blocking a nice chunk of openning though so I think I'll remove one of them. The trans temps have been very low anyway, the hottest ATF temp I've seen is 180 deg.

Bob Bridge Toyota send me a 160 deg t-stat but its not a "TRD" highflow t-stat. In fact its got a smaller openning than the stock one has. Here's some pics of the stock 5VZ 180 deg on the bottom and the 160 deg they sent me on top (part# PTR01-21050-95). Needless to say its going back to Bob Bridge ASAP.

 

tell me more about the overheating problem. how much does the temperature fluctuate? does it only overheat on the interstate with the ac? what temp will it hold just sitting and idling?

 

Well like today I drove about 22 miles and it varied from 185 to 203 with the AC on all the way. Its hottest at higher speeds, like 70-75. Idling at stop lights it cools down to 185-low 190s. Ambient temps were around 80 deg during the drive.

 

I noticed this happend with my snow plow truck this winter on warmer days when i had the plow to high. I think your radiator man has the right track with the bumper/winch. I would try removing the winch and seeing if that makes a differnce. Obviously this isnt a solution because you want the winch but it would isolate the issue more for you. Another option you might consider if it is the winch, is mounting the winch on a reciever so you could not only move it front to back, but also put it in your truck bed when it wasnt in use (going down the freeway) if indeed it is the issue.

 

I found another idea today, waterless coolant:
http://www.custommachiningusa.com/Evans_NPG+.html
Anyone used anything like this in a vehicle? I noticed they suggest aluminum radiators, that would be nice too but about they cost lots of $$$.

I started a thread about the Evans waterless coolant here:
https://www.yotatech.com/forums/f123/evans-npg-waterless-coolant-114994/

 

I found this post today over on TTORA:
http://www.tacomaterritory.com/forum...54&postcount=6
Note: his mods, ARB bullbar,33s, SCer and 7th injector (that comes with a TRD 160 deg t-stat BTW)

 

Well I called Barb @ Toyota of Dallas, I should have called them to begin with, unlike Bob Bridge Toyota, at least they know what a TRD part is. http://www.trademotion.com/partlocat...?siteid=214074

She said the TRD t-stat had been discontinued and was no longer avaliable. She said TRD still has them in the 7th injector kits though and suggested I call TRD (888-551-2929). I called TRD and they said they were avaliable and gave me a # PTR-01-35050-01. So I called Barb back and ordered one, list price about $90...special Yotatech internet price $65.55, that must be one special t-stat Should be shipping tommorrow.

 

Hope its gold plated and brews beer for you

hopefully that does the trick, I think you have done everything else.

 

Nope not everything else, I still could get a custom $500 aluminum radiator that may even distill moonshine too.

 

Is this a truck or a money pit

 

Come on, do you even have to ask? But at least it's been paid off.

 

I have to say Dale, I think getting (or making) a tube bumper would get rid of your problems... something that allowed more flow in and around the winch.

I'm sure you could sell your ARB for a pretty penny...

 

That will be a last resort thing, however I went to use my winch yesterday and it didn't work so I maybe taking the bumper off to figure out what's wrong with it. If so, I'll take a little test drive with no bumper to see.

Another thing I haven't tried is bypassing the ATF cooler but I'm not too hopeful that will help since my ATF temp going into the radiator is about 180 max right now. Not sure what the coolant temp is at the bottom the radiator where the ATF heat exchanger is but if its hotter than the ATF then you see where the ATF is actually taking some heat out of the radiator.

 

Well I got the TRD 160 deg t-stat:


I did some testing on it and the stock 180 deg together, with some hopeful results. I've heard some say that the t-stat only determines the low temp, not the high temp, but my testing shows a wider opening passage to the radiator through the entire normal operating temp range.









What I tested:


The other 160 deg t-stat was what was first sent to me by Bob Bridge Toyota as supposely a "TRD t-stat" I knew something was wrong when I saw the plain white box and the made in Canada label. It was definitely different, seems to be cheaply made even though it was $36. It opened wider than the stock 180 deg through the whole range of testing but not as wide as the TRD. It also opened a little later than the TRD, closer to 165 than 160.

 

Hope that works for you Dale.

 

Thanks John, hope so too.

 

So where did you find your TRD stat?