Possible overheating issue

[Toast]

Got an interesting situation here...
My existing cooling setup has worked great with no issues for years, in fact I've never had an overheating issue ever. My old dated existing 3row radiator developed a small pinhole leak ( at least I think ) when I started to notice a small amount of coolant here and there along the top of the radiator. Figured it was time to replace it so I bought a new CSF 3 row rad along with new cap and top hose. Also currently running the black magic electric fan but decided to drop a new one in for good measure.
So to recap we have a new radiator, fan, hose and cap. Currently running auto meter short sweep gauge with the sending unit in the back lower section of the block where the coolant drain port is. Never had an issue, truck ran between 180*-195* and would very rarely creep over that. During the rad swap i failed to wire my fan properly and by the time i figured it out my coolant began to boil over... oops (212* @ atmosphere). I shut off the truck and let the coolant settle out in my spill proof funnel. Figured nothing was hurt because 212* isn't crazy hot by any means for a rig. Figured I would mention this just in case it could have done something. Got the fan going and burped the system and off I went. Truck slowly got hotter and hotter while driving (220*-230*) but when I would stop and let it idle it would start to cool off. With a temp gun I was measuring 175*-185* at the stat housing and top rad inlet. Figured the t stat was the issues so i replaced it with an aftermarket one to see if it fixed the issue. It definitely appeared as if the issue had been resolved but the next day when I went up a long grade it started to overheat again. Same thing as before with things under the hood temping normal but gauge is reading high. This has me stumpted big time. So possibilities are:
-Bad sensing unit for temp gauge
-Bad aftermarket thermostat
-New radiator faulty? (doubtful but it is aftermarket)
-New fan not moving enough air? (not likely)

I have an OEM thermostat and new sending unit on standby but I also feel compelled to put the old radiator back in to see if that changes anything. The problem with doing everything at once is you don't know the specific thing that fixed the problem. Thoughts on where the sending unit is located? I figured the coolant cant have that much difference in temp there vs the factory location. Any and all input is appreciated, Thanks!

 

[gnob]

sounds like the radiator.
i thought someone else just posted a similar scenario with the csf

 

[Toast]

Well it’s not the temp sending unit and there’s definitely not air in the system. Re bled the system up hill. I’m gonna swap in the old radiator and fan to see what I find…

 

[Toast]

Update: so I have suspected my truck has been running lean for a while now based on my higher than normal nox levels and slight pinging here and there. Adjusted timing, adjusted valve lash
(3 exhaust valves were tight and holding open)
Plugs are pretty white and crusty, definitely showing signs of running lean. I’ll replace those along with a new O2 sensor. Adjusted TPS and finally I decided to replace my AFM with one of those Chinese EBAY ones. Definitely sounds more responsive and smooth. All of this because I thought maybe running lean was driving up my internal temperatures. Ok, back to the cooling issue. Swapped back in a OEM thermostat along with my original radiator and fan. Pulled the block plug and there was a bit of junk built up in there but nothing crazy. Cleaned and reinstalled, Bled the system of air and the system is staying rock solid at 180* which is where it used to sit when the truck was at idle. Crossing my fingers that it stays under 195* during my test drive tomorrow.

 

[Toast]

Well hope this massive time / money suck can help someone. DO NOT buy a CSF radiator. I’m sure there are plenty of people who have had good results but it’s not worth the gamble if you ask me. The cooling system is definitely something you can’t chance. I was looking through threads in the cruiser forums and I found multiple people who had experienced the exact same issue as me and narrowed it down to the CSF. I reinstalled my old radiator and all my issues vanished. Going to have to find a different solution for my radiator replacement. Any suggestions?

 

[pappy]

Any suggestions?

I just installed a KoyoRad. Aluminum. I did have an install issue. The mount for the shroud is wrong. It pushed the shroud too far into the engine instead of being right on the radiator.

I cut the bracket, and pop rivet it back on in the correct place so the shroud was right.

 

[Toast]

Got any pics of your Koyorad? I’ve seen those but saw a few bad reviews so I am a bit skeptical. Currently I was looking to find a used OEM radiator and have it gone through but the Koyorad looks pretty nice

 

[RichardSkinner]

Check my post about rad upgrade and e-fan setup. So far I like the change.

Builds - RockGoat Version 3RZ

OK, what are your thoughts on using a 1990-95 V6 fan shroud and fan? I seem to recall someplace seeing it's a bolt in to our radiators. I haven't heard whether the 3.0 fan bolts up to the 3rz or if the 3.0 shroud lines up correctly

forum.ih8mud.com

 

[Toast]

Check my post about rad upgrade and e-fan setup. So far I like the change.

Builds - RockGoat Version 3RZ

OK, what are your thoughts on using a 1990-95 V6 fan shroud and fan? I seem to recall someplace seeing it's a bolt in to our radiators. I haven't heard whether the 3.0 fan bolts up to the 3rz or if the 3.0 shroud lines up correctly

forum.ih8mud.com

Very cool! I currently have the flex a lite black magic fan setup sold by LCE paired with a 3 core v6 rad. Setup works great but I'm struggling to source another OEM V6 radiator. I was eyeing the aluminum radiators but keep hearing people having issues with them. Champion seams to be a pretty decent brand from what I gather. I really like the amp draw on your fan and the variable speed controller makes so much sense. My fan is in great shape and would hate to ditch it strictly for a reduced amp load but its something to consider for the future. Where did you get that aluminum shroud to back your radiator and is it absolutely necessary? Really appreciate the feedback. Definitely leaning towards a aluminum radiator though.

 

[Toast]

Does anyone know if the v6 champion radiator will fit the 84-88 rigs?

 

[pappy]

Got any pics of your Koyorad? I’ve seen those but saw a few bad reviews so I am a bit skeptical.

Before the shroud. You can see how the shroud mount sticks out into the engine (22RE). The shroud not only had a gap at the engine, it hit my AC.

The modification of the shroud mount. Mount bolts off, so this is an easy fix. I clamped some angle on the mount to work as a guide, and cut it off about an inch (maybe less) using a Diablo saw blade on my circular saw. I mounted the shroud to the pieces I cut off, positioned them on the radiator, marked, then drilled for pop rivets.

Note that the Koyorad is a thicker radiator, but only has two wide cores.

 

[pappy]

For the ultimate radiator see Ron Davis Radiators. Just don't be too surprised when they quote you over $1K..

 

[Toast]

I wonder if Koyorad knows that their radiator requires modifications? I would think they have to know but I’m sure I would have to do this for the electric fan setup. That radiator looks great by the way

 

[Toast]

How is the Koyorad holding up? Have you noticed any difference in cooling? Pretty sure I'm going to go with one of these

 

[pappy]

How is the Koyorad holding up? Have you noticed any difference in cooling? Pretty sure I'm going to go with one of these

It's cooling my supercharged 3RZ just fine.

 

[RichardSkinner]

Very cool! I currently have the flex a lite black magic fan setup sold by LCE paired with a 3 core v6 rad. Setup works great but I'm struggling to source another OEM V6 radiator. I was eyeing the aluminum radiators but keep hearing people having issues with them. Champion seams to be a pretty decent brand from what I gather. I really like the amp draw on your fan and the variable speed controller makes so much sense. My fan is in great shape and would hate to ditch it strictly for a reduced amp load but its something to consider for the future. Where did you get that aluminum shroud to back your radiator and is it absolutely necessary? Really appreciate the feedback. Definitely leaning towards a aluminum radiator though.

If your charging system is doing fine with the load, then I wouldn't worry about it unless you add more stuff. I haven't posted yet but I have a lot of extra electrical load on my system - namely an isolated auxillary battery and upgraded alternator.

I made the shroud. I wasn't a fan (ba dum dum tssss) of the efan shroud options out there and I do believe shrouds are very necessary and that you do want standoff built into them. Some of the cheap 22RE aluminum rad combos have shrouds that are just flat panels the efan mounts to. That effectively reduces the useful cross section of the radiator to just the diameter of the fan because no flow can be pulled through anything outside the radius of the fan. Some try to defeat this by putting slotting in the corners that should have flaps on them in order to allow air to flow when you are moving, but the flaps are intended to "suck shut" when the fan is pulling. I dunno, might work, but seems like a bandaid to me.

 

[Toast]

Figured I’d finish this thread off. Ended up having OE radiator rodded out and rebuilt. $165 later and I can’t get the truck to get hotter that 195 and it’s been over 100* in the greater Sacramento area lately. Needless to say I am very happy. Gotta love Toyota quality; their 30 year old radiator out performed a new one… I still am super curious what was wrong with the CSF radiator. Anyways, those 90-95 4Runner M/T radiators are getting very hard to find so if you ever come across one, grab it. Thanks dudes!