How does it work? The ones I've seen pressurize the system through the radiator neck ... but that's the part I need to test.
What rad cap are you running on you're TYC radiator??
- Thread starter JM74
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COS80
SILVER Star
Same.
So, I didn't read this thread exhaustively, so this may be totally off base, but I remember seeing it in a thread here somewhere...
Aftermarket rad, stock cap, and the overflow was welded to the neck, a hair too close to the cap and it was ever so slightly lifting the cap causing it to leak when at top pressure. They literally notched the sheet metal on the edge of the cap so it had a little clearance when in the close position, and it solved the problem. May have nothing to do with your situation, but I thought i'd throw it out there.
Aftermarket rad, stock cap, and the overflow was welded to the neck, a hair too close to the cap and it was ever so slightly lifting the cap causing it to leak when at top pressure. They literally notched the sheet metal on the edge of the cap so it had a little clearance when in the close position, and it solved the problem. May have nothing to do with your situation, but I thought i'd throw it out there.
Interesting - I'll take a look at that in the daylight tomorrow.
Not 100% but isn’t a stock LS rad cap 18psi pressure effectively making the boiling point higher? Maybe you should try a higher pressure cap that’s closer to stock for a LS I’m thinking a cap for a 200 series might work and provide more pressure than one for a 80 series. I could be off base on this one though.
Everything I've seen indicates a 13 psi cap for the 80 series.
I guess I'd be concerned about putting a higher pressure cap on a radiator built for 13 psi.
I think the problem is that the cap isn't sealing at all - boiling at 220ish indicates it isn't holding any pressure, not that it's exceeding the 13psi cap. So putting a higher pressure cap on it isn't likely to do anything.
But it's any easy & cheap try, so I'll put it on my list.
But it's any easy & cheap try, so I'll put it on my list.
Good point. My research verifies your statement:
"A factory GM LS V8 cooling system typically uses a radiator or surge tank cap rated between 15 to 18 PSI. Stock fourth-generation LS applications frequently specify an 18 PSI cap, while custom LS engine swaps generally run safely with a standard 16 to 18 PSI rating depending on the specific radiator core and hoses used. [1, 2]" when I googled: "LS v8 engine radiator cap rating"
What are you looking at? The LS engine doesn't know or care that it's now in a 80 series Land Cruiser that previously had a 13 lb radiator rating engine in it. IMHO you need to satisfy what the GM OEM parameters require or modify the LS ECU.
Edit: You may even need a higher rated radiator.
The radiator is built for an 80 series that specced a 13psi cap. So presumably it's built for 13psi and 18psi is above that. That's an additional roughly 250 pounds trying to separate the top tank from the core. Is that a problem? I don't know but it makes the engineer in me twitch a bit.
But again, I don't think it's relevant. Because as it stands, I don't think the cap is sealing at all so it will never see either pressure.
I would say the radiator and cap are over matched. You should have a cooling system that all the components are rated to what is specified for your current engine. The TYC radiator that you have now is rated for the 80 series OEM engine, but I doubt that it's rated for an LS V8 engine, which is what you have.
I’d be less concerned whether or not the sacrificial lamb of a cheap radiator can take it as opposed to whether or not the engine can take it… which costs more. It’s obvious when a radiator can take it. If you check your engine as often as you should on a 30 year old truck and test it real world with data and a pinch of skepticism as one should when modifying a chassis / engine combo. I’d put good money the radiator can take it no prob but if your really that worried remember a bonded 1/8 inch tops! Plastic expansion tank is where the 16-18lbs takes all of the 200-210 degree heat soaks and pressure of a LS and that plastic garbage usually outlasts the water pump and often the radiator in a LS equipped 5.3-6.0L vehicle. Either play with aftermarket questionable 160-180 T stats or play with a 16 / 1.1 bar cap for a 200 series. I’ve offered solutions here this is exactly the process of how I’d go about this problem before trying to customize a radiator set up to accept a GM expansion tank. Which I think would be a complete waste of time and effort.
Lots of overthinking the issue, it was a common problem with the TYC radiator years ago. The neck is cast/molded crooked on some, it just needs a radiator cap with more depth. Pretty sure the Sankei brand cap solved the issue.
Kyle
Kyle
Also not to pile on but the OE stock radiators on a 80 series brand new were built like brick s***tx houses compared to a LS equipped Chevy ( insert model here ). If you could figure out a way to drop 10 degrees that’s all you really need to do.
Maybe solved...
I set up this system on the radiator steam nipple.
It lets me pressurize the cooling system with the air compressor.
I tried the old cap, the new OEM cap from the dealership and the Autozone cap. All were leaking through into the overflow before the regulator needle even came off the peg. So the radiator wasn't holding any pressure at all. To all those recommending a higher pressure cap - won't do any more good then the low pressure caps if it doesn't seal at all.
My guess is the neck on the TYC radiator is a little to tall so the cap plunger won't seat & hold pressure.
Next I tried the two caps I just got on Amazon.
Amazon.com - https://www.amazon.com/dp/B096MR3YMH Radiator Cap 13 PSI 0.9 Bar For Toyota Camry Corolla 4Runner Land Cruiser, Honda Accord Civic Prelude, Nissan Mazda Mitsubishi Subaru Lexus Infiniti, # 1306J1 16401-63010 16401-71010 16401-87710
This one held some pressure! A bit over the first line on the regulator, about 5 PSI.
Amazon.com: Gates 31533 Safety Release Radiator Cap : Automotive - https://www.amazon.com/dp/B000C2WF4U Gates 31533 Safety Release Radiator Cap
This one held to about midway between the first and second lines on the regulator, so 12-13ish pounds. This regulator goes to 200 PSI, so not ideal for measuring low pressure like this. I have a low pressure one on order that will offer a bit more precision.
I noticed that both of these caps still felt a little loose when screwing them on. So I tried bending the tabs on the cap a bit.
They definitely go on a little harder. Now the Gates one will hold to just below the second line on the regulator, so 14-15ish psi. Doing the same with the other new cap brought it up to about the mid point.
Doing the same on the autozone cap got the needle to come off the peg just a little. So bending the tabs alone isn't necessarily a solution.
Now I just need another hot day to try it. Today is pretty cool.
I set up this system on the radiator steam nipple.
It lets me pressurize the cooling system with the air compressor.
I tried the old cap, the new OEM cap from the dealership and the Autozone cap. All were leaking through into the overflow before the regulator needle even came off the peg. So the radiator wasn't holding any pressure at all. To all those recommending a higher pressure cap - won't do any more good then the low pressure caps if it doesn't seal at all.
My guess is the neck on the TYC radiator is a little to tall so the cap plunger won't seat & hold pressure.
Next I tried the two caps I just got on Amazon.
Amazon.com - https://www.amazon.com/dp/B096MR3YMH Radiator Cap 13 PSI 0.9 Bar For Toyota Camry Corolla 4Runner Land Cruiser, Honda Accord Civic Prelude, Nissan Mazda Mitsubishi Subaru Lexus Infiniti, # 1306J1 16401-63010 16401-71010 16401-87710
This one held some pressure! A bit over the first line on the regulator, about 5 PSI.
Amazon.com: Gates 31533 Safety Release Radiator Cap : Automotive - https://www.amazon.com/dp/B000C2WF4U Gates 31533 Safety Release Radiator Cap
This one held to about midway between the first and second lines on the regulator, so 12-13ish pounds. This regulator goes to 200 PSI, so not ideal for measuring low pressure like this. I have a low pressure one on order that will offer a bit more precision.
I noticed that both of these caps still felt a little loose when screwing them on. So I tried bending the tabs on the cap a bit.
They definitely go on a little harder. Now the Gates one will hold to just below the second line on the regulator, so 14-15ish psi. Doing the same with the other new cap brought it up to about the mid point.
Doing the same on the autozone cap got the needle to come off the peg just a little. So bending the tabs alone isn't necessarily a solution.
Now I just need another hot day to try it. Today is pretty cool.