Plastic tank radiator


Believe nothing you hear and half of what you see.
Dec 9, 2002
My friends and posters here have had plenty of discussions on plastic tank radiators. Many use them on Turbo Buicks, others have stong reservations. The all aluminum radiator choices that are "direct fit" are getting scarce. Even those "direct fit" seem to not be that direct. A local guru here that has a 9 second car and works for customers did an install on a GN that he has owned for years and recently sold. The new owner brought it to him and the two proceeded to install the "direct fit" that the customer bought. Well, this experienced TB guru and his helper took 5 hours for this install. He was pissed and will never install that brand again. So the choices in plastic tanks is small too. Rock Auto has a few on their website specific to the TB. You can also use the F body without the oil cooler and different location trans line and radiator hose locations. Not a huge issue but not "direct fit". I've looked at the other G body plastic tank radiators that could work and found the CU570 which might work. I don't know anyone that has tried that. Most plastic tank radiators I've seen are the Fbody. So the big question with the plastic tank radiators that we have talked alot about is can they handle the rigors of a TB. I have seen an all aluminum radiator that was pressurized by a blown head gasket that pushed combustion chamber pressure into the system. The end tanks bowed out but it didn't fail. So the question is how would a plastic tank radiator behave if hit with high pressure. Others worry the plastic will age and split or crack.
V8Killer had a B body plastic tank radiator hanging around. It was used and at least 5 years old. He decided to see what happens when you pump it up with shop air. The ambulance repair shop he runs uses 145psi in their air lines. He blocked off the outlets and gave it hell. All the time he was scared it would blow up in his face. This is what happened:


So V8Killer can't say exactly how much pressure was in the tank but clearly the aluminum bowed out. The end tanks did not blow off or split or crack. I can't say this is definitive evidence a plastic tank won't blow off or crack but I think it shows they can take a hell of a lot of abuse. Looking at new vehicles, all use an aluminum radiator with plastic end tanks. Everything from a putt putt to a ZL1 Corvette. If the OEM manufactures have enough faith in them surviving then they must be half way reliable. V8Killer and I have decided the plastic alternatives are not a threat to blow a tank. We think the more likely item that would fail is a hose under extreme pressure.
CU570 is what I run .16 lb cap will open long before you will hurt the radiator. What you have there is some Tomfoolery and maybe some alcohol.
Hoses are in the right spot and size for Turbo Buick unlike F body. Inexpensive light and it works.
My car is just 11.5 car but I think it would work into the 10s . Temperature stays 160 to and from track AC on and never above 180 hot lapping.
I like how a lot of people claim plastic radiators are just going to explode left and right....

...yet auto manufactures will install millions of them on cars that they warranty.

Think about it... If they were half as bad as they're made out to be, it would costs billions in recalls, engine replacements, product updates, and lawsuits. Yet they do just fine.
My reservations about plastic end tanks has nothing to do with performance. I had one in my BMW years ago that gave up the ghost on me during a trip. The plastic developed a crack in it, while the rest of the rad looked mint. There are no signs or symptoms that warns you about this until it lets go and leaves you stranded. I just don't like the idea of mixing plastic and aluminum together in such a crucial component. Some have great success, others not so much. The one thing I will not do with a plastic end tank, is run any oil or tranny fluid through it as a cooler. That is a accident waiting to happen. The Dodge Neon's are a prime example of the transmissions getting destroyed when the rad lets go.
Lots of other things to worry about. Tits or tires kinda deal. We put a great deal of faith in one u joint don't we? If that breaks its a bad day too. Just one example. Not busting balls, to each his own.
I like how a lot of people claim plastic radiators are just going to explode left and right....

...yet auto manufactures will install millions of them on cars that they warranty.

Think about it... If they were half as bad as they're made out to be, it would costs billions in recalls, engine replacements, product updates, and lawsuits. Yet they do just fine.
Not arguing that they'll work well in a number of situations but all manufacturers care about is that their cheap products make it out of warranty so they don't pay and the customer does. Massive profits are what they're all about.
The first thing that comes to mind is GM and others with their piss poor brake, fuel, transmission, etc lines that literally rot soon after if not before warranty expires. Look at VW, not that I think it was bad for customers but they played games and got caught to the tune of billions. Pinto, Vega, they've played the cheap for decades. Guess that's why the aftermarket comes to the rescue many times.
The Sierra has the plastic one and after 13 years its still going but only has 72K on it. The best part is no petcock to drain the coolant out. Cheap is the business model for practically everything out there, not just autos.
All the plastic tank radiators that I've seen fit the TB have drains of some sort. Not a petcock facing down like the stock brass radiator has but there is a way to drain it.
I suppose if you are afraid of old plastic cracking or the coolant line leaking coolant into a trans line you could replace the radiator after year since the Fbody one is under $100 and just call it maintenance like the alky pump.
I'm 60 years old. I can remember when all radiators were brass and copper. I also remember them developing leaks and cracks regularly. Radiator shops were on every corner and they had to do recores all the time because of pinhole leaks. All those joints brazed were subject to failure especially after a "radiator flush". I contend the repair rate and/or failure rate of a stock TB radiator and a plastic tank one is pretty much equal or better for the the plastic tank. My 1999 Sierra 2500 is still fine. How many 20 year old TB radiators were all corroded and had pin holes? I know my original one got all pinholes in it and had to be replace shortly after I got it. At that time it was less than 20 years old.
True on the brake lines. My dad got rid of a 2000 tahoe and we never put a radiator in it and it had 280,000 on the clock. Also never put an o2 sensor or any exhaust part on it. It was all still sealed up nice. Seems random.
My nickle on this- when I found my Turbo T the original radiator was in bad shape, leaking everywhere/pin hole leaks and the tanks were both shot. Being a novice, I needed a radiator to even begin work on her and ordered the Rock Auto replacement with the stock Oil and Trans Cooler lines. 1 year later I am still running the plastic tank radiator. I do believe that a Be Kool or equivalent is a much better radiator long term. I agree with Pronto though, at $100 and some change it does the job until you can afford/need an upgrade.