Fzj80 with 1fzfe radiator upgrade (1 Viewer)

[Woofythewolf]

I posted a video on these forums of what happened immediately after the AC stopped working (so I was above 227F). The coolant was boiling in the reservoir bottle and the the entire top of the radiator was steaming and boiling coolant was coming out of the top seams. The radiator cap did its job too well--it never gave way. Not great videos, but here they are: Cooling Situation...Is This Normal?

Oh I see. so you were sending a huge volume of gas out and the small outlet couldn't keep up. Crazy that could happen even with a 3 month old OEM radiator cap. When I was going up the grapevine I was fairly heavily loaded for moving, but I made sure to keep the speed up above 55 (I had the pedal to the floor at maybe 3600 rpm). Vehicle speed will do far more than the fan could ever hope to do.

I wonder if people who really work their vehicles hard should go for the pure glycol coolant. It doesn't boil until 310F or something like that, so it will literally never boil over and lose cooling performance.
Edit: Evans Waterless Coolant, Prevent Engine Overheating

 

[Broski]

I'll give you the numbers I have from a '94 purchased with 277k and the original brass radiator. Temp readings are from a Toyocom, stock fan and coolant wass Prestone green.

1st readings (average) from November - January in Las Vegas
Highway speeds (65-70mph) and no AC: 186F (max 187F)
City driving and no AC: 191F (Max 194F)

That radiator cracked while offroading in January 2020 and I installed a Koyorad A1918. Coolant was Prestone green

2nd readings started in June when it regularly gets well over 100F in Las Vegas
Highway speeds with AC: 194F (Max 196F)
City driving with AC: 199F (Max 206F)
Idling with AC: Max 212F

The Koyorad only lasted until July. I slugged the motor going up an off-road mountain pass and blew the top (I know, I should have been in a lower gear...). This time, I went back and purchased a used original brass radiator (cash was tight) and used Peak Final Charge Global Extended Life red coolant after flushing the system with distilled water.

3rd set of readings from June-August in and around Las Vegas
Highway speeds with AC: 194F (Max 196F)
City driving with AC: 196F (Max 204F)
Idling with AC: Max 212F

Personally, I didn't see a significant performance difference between the stock brass radiator and the A1918, and I know that I said that the brass radiator was better than the Koyorad, but that's because the original brass radiator lasted the PO and myself nearly 280k miles before it crapped out. Until someone says their koyorad has lasted for about that long, the OEM has the edge despite new ones being about double the price. Still, I wouldn't hesitate to pick up a Koyorad. Just don't overtax the motor like I did and I think you'll be fine.

Very good info. My Reg runs with very close to the same temps. I have seen higher temps with the AC on when hard core rock crawling but as long as I don't run the AC it's fine. The issue is when it 100F out I want the AC on.
Some performance radiator suppliers advertise a 20 degrees drop in temp guaranteed with there radiators ( Be Cool Radiators ) this would allow me to run the AC when it's hot out and I'm rock crawling.

 

[Woofythewolf]

In that case you have a low speed air flow issue. What you probably want is a couple of electric fans on the front.

That would be the most likely culprit I think, and is the easiest/cheapest solution that will still provide benefits regardless of which way you go.

I’m not convinced on the aftermarket radiator’s “20 degrees guaranteed” claim, cause if there’s barely any airflow in the first place and it’s only dropping coolant temps by 5 degrees across the rad, there is no way they are going to achieve 5x the cooling performance in a similar form factor. An absolute temperature drop just isn't something that can be claimed on a heat transfer device, as it’s too dependent on other variables.

if they said something like a 10% increase in cooling performance, I’d believe them and trust them as a brand a lot more. But claiming 20 degrees is just BS and shows a lack of knowledge on the very basics of heat transfer, from a company who is supposed to be making radiators.

 

[TYM4FUN]

In that case you have a low speed air flow issue. What you probably want is a couple of electric fans on the front.

Agree. Aux A/C fan solved my heat issue when wheeling.