What rad cap are you running on you're TYC radiator?? (1 Viewer)

[JM74]

Over the winter I ended up rebuilding the top end of my 1FZ, its supercharged and had always seemed to run a little hot during the summer months before. So while rebuilding I decided to try a TYC radiator that seemed to be raved about its cooling abilities, I understand it's a cheap radiator but figured id try it out. The days are getting hotter now and it seems to be doing the trick to be honest I rarely see above 200 now.

Anyways my issue is when I park the truck and come back to it in the morning or after a day or so there is a small puddle of coolant on the ground on the left side towards the lower rad hose (looks like its coming from there), I think the cooling system is building up a lot of pressure because the rad cap I'm using isn't allowing for it to release any... I running a OEM toyota rad cap.

Everything else seems to be functioning well. When I check coolant levels they are still very high and its only leaking a little bit, when I pull the rad cap off you can hear a woosh of pressure being released.

Just wondering what all you AZ guys are running for rad caps on your TYC radiators...

 

[ChaseTruck]

On our '93 with the TYC, the Toyota cap didn't seal enough. No issues at around 1500 - 3,000 feet elevation, but it did become an issue trying the Bear Tooth Highway in Wyoming two summers ago, it boiled over when parked at the Yellowstone Overlook at 8,750 feet elevation. Autozone in Cody to the rescue for a new radiator cap, bought both kinds they had, one fit nice and tight, haven't had any issues since, but haven't had the truck up that high, either.
Other than that, perhaps @richardlillard1 would have more precise info?

 

[JM74]

On our '93 with the TYC, the Toyota cap didn't seal enough. No issues at around 1500 - 3,000 feet elevation, but it did become an issue trying the Bear Tooth Highway in Wyoming two summers ago, it boiled over when parked at the Yellowstone Overlook at 8,750 feet elevation. Autozone in Cody to the rescue for a new radiator cap, bought both kinds they had, one fit nice and tight, haven't had any issues since, but haven't had the truck up that high, either.
Other than that, perhaps @richardlillard1 would have more precise info?

Cheers appreciate the info! Did you find that you lost any coolant due to excess pressure with the Toyota cap at all?

Also any chance you know the brand / model of the cap you ended up going with, I have a bunch of extra caps around that I ordered off rockauto a while ago..

 

[ChaseTruck]

Yes, coolant did boil out of the overflow; added some drinking water and moved on. Beartooth Hwy was closed due to snow anyways (on June 8... some guys were dragging their snowmobiles up there), we just wanted to see how far up we could get. Rolled back down and proceeded on Chief Joseph Hwy.

Don't remember what cap, and can't look since I'm not in AZ right now. Cap is square and has a red locking lever thingy... no issues running desert trails in AZ at 110-115°F ambient temps

 

[LongDuck]

Red locking lever sounds like "Stant" brand, common to auto parts stores. Not sure about quality, but I've only ever run a Toyota OEM part, and as long as you open up the Radiator Cap when the engine and coolant are COLD every once in awhile, it doesn't seem to have problems.

Edited; clarified to check the Radiator coolant level directly from time to time, by opening the Radiator Cap when the engine is COLD to prevent seals sticking in place and preventing proper venting.

 

[JM74]

Red locking lever sounds like "Stant" brand, common to auto parts stores. Not sure about quality, but I've only ever run a Toyota OEM part, and as long as you open it up every once in awhile, it doesn't seem to have problems.

think i should have one of those to be honest. Ill have to search through my parts stash.

If you open up the system and let is de-pressurize it should be fine? what about long continuous drives

 

[LongDuck]

Sorry, to be clear - my comment about opening it up occasionally means, when the engine is cold, remove the Radiator Cap and look into the Radiator top tank to be sure it's full to the top. Also, check your overflow reservoir to be sure it's filled to the Fill line, and then replace the Radiator Cap.

My problem was that I went for YEARS without touching the Radiator Cap because I trusted the overflow bottle to tell me if it was full. In my case, the rubber seal glued itself to the OEM Toyota radiator fill port over time, and I didn't know it. On a supremely hot day, going uphill with no airflow, the Radiator top tank exploded just like in the video, as there was no way for my radiator to vent - with the Cap glued in place. The only venting I got was when the top tank exploded.

Only remove the Radiator Cap when the engine and coolant are COLD. Never open a hot radiator cap.

 

[ChaseTruck]

Haven't noticed any temp problems on long climbs like the one on I-17 up to Flagstaff at ~7,000 feet. On the above episode on Beartooth, no indication of anything really untoward on the Koso gauge (it's a S/C'ed '93, so OBDI; gauge sensor in the head coolant outlet). These trucks overheat anyways when you turn the engine off and the heat soak comes to full bloom without the benefit of circulating coolant, and that's what happened... in the winter, an 80 makes a fine garage heater.

Turned the engine on, let it idle, temps dropped immediately, and it sucked coolant/water from the reservoir. Opening up the hot system to depressurize is asking for trouble/injuries to whoever turns the rad cap. Better to try and squirt cold water at the front of the truck while it's idling.

As for the cooling system on the truck, it's got a TYC radiator, the 170°F thermostat spec'd for the S/C, a stock fan (not the S/C fan or the 3FE fan...) with a custom spacer to clear the S/C belt, the water pump overdrive pulley, a juiced blue fan clutch at about 35k, the regular fan shroud, and Home Depot-sourced foam to seal the edges of the radiator.

 

[Desert Dino]

I am using a Toyota rad cap on my TYC, I check coolant level every morning when cold no problems no need to add coolant. you need to push it down hard when rotating it is not a perfect match

once i left it semi open because it is not a perfect match i lost 1/2 a gallon of coolant and I learned my lesson

other then that it works perfectly, coolant moves back and forth from the rad to the expansion tank on hot cold cycles.