Will,
If you were looking at 928 radiators they would be.

Porsche/Mercedes were having issues with overheating back in the 80s I believe. They developed the turbulent radiator to get more efficiency out of the existing size of rad. They added what I would describe as a "ladder" within the existing core that agitated the water as it passed through the rad thereby exposing more of the water to the fins.

Just lately I have been playing with radiators from the view point of purchase, replace and repair and learnt a lot in the process. I am not an expert but just soaking up info. Everyone I have talked to and a lot were long time Behr people confirmed the story about the turbulent design.
There is no where to push a rod through and even if you were you cannot reach all the crud that builds up around the ladder.

I have one bad rad that I may cut up to prove the point to myself.

Normy,
Sean at the P car GTG here in DFW has a Devek radiator and it was leaking in two places. Someone told me that they are built here in TX.
I wonder if the one sold by 928 International has any better performance than the Devek unit when it comes to length of service. I hope Mark or Jim jump in at some time.

 

I had a Devek radiator in my 89 GT for over three years with no problems at all. DEVEK recommends grounding the radiator to retard corrosion. Ron Davis, manufactures these for Devek. He said: 1) Electrolysis, in other words corrosion. If the coolant is not replaced on a regular basis, acids will form. The aluminum radiator becomes the sacrificial lamb. Better that then your heads or block! 2) Installing serious stereo systems without proper ground seems to have an adverse effect on aluminum radiators as well. Not sure why, but I assume the radiator becomes an anode and the effects of large amperage is carried thru the coolant. 3) Ron Davis asks anyone who has a problem to call him @ 623 877 5000. (623 is an Arizona area code, not Texas.) Don't let the receptionist forward you to customer service, talk to the man himself. He will deal with any issue on a case-by-case basis. He says the average return rate is 2%, and even less on the 928, because Porsche owners tend to take better care of their cars. Devek does not knowingly sell inferior radiators. Ron Davis, is an upstanding, forthright individual. The quality of his products speaks for itself, and can be easily verified by a visual inspection.

Jim Mayzurk
93 GTS 5-spd

 

928Intl has C&R make their radiators.

Is there any standard for measuring radiator performance, like X gals per min of water and Y cfm of air and you get Z degrees of temperature drop? (with some reference value for input air and water temps like 100F and 200F).

Whats considered the best radiator design these days, or just use a big one?

 

Jim, that's great to know, but the thing is that when I bought this $800 part, none of this information was provided to me. I usually change out coolant in my cars every two years, and I like to run a 60/40 or 70/30 water/coolant ratio here in Florida, since the higher water content enhances the radiator's efficiency.

I haven't talked to Ron Davis, but when I talked to Devek [Susan] on the phone, she was very helpful and accomodating, and sent me a link to a website that talks about radiator electrolysis. Great information, while my radiator leaks in the garage. The long and short is that these aftermarket parts are made out of materials that are not up to Porsche OEM standards. Ron Davis Racing manufactures radiators for race cars- Nextel Cup cars use these things. But Nextel cup cars don't need to drive around for 10 years with the same radiator, so you get the idea.

I think Devek is a great company, and if I need a part for my 928 I still consider them via their website [I have Porsche original motor mounts from them, I bought them after this fiasco] but at the same time I still don't think that an $800 part should fail within 3 years, irregardless of the 12 month warrantee. Cheesy Behr radiators generally last 15+ years.

N!

 

I got more than a few snickers when I showed up with Walmart distilled water to go with the DexCool, but at $0.69/gal why not?

School kids around here do science fair exhibits with batteries made from tap water and nails.

 

Yup, mines a leaker after 4-5 years of use.

I'm going to go with Rog and Jim on this and see about having it rebuilt via thier suggestions instead of spending $8-900 on a new one. It is interesting to hear about radiator electrolysis, I would have had no idea on this. Something as simple as a ground on the rad to keep it in better health.

As far as not using distilled, when we changed my H2O pump you could see the corrosion on the inside of the pump from others just dumping tap water in there. I'm pretty sure that is what has caused my rad to fail. Keeping a few gallons of distilled around will help prevent this.

 

ROG100 wrote: "Will, If you were looking at 928 radiators they would be.
Porsche/Mercedes were having issues with overheating ... They added what I would describe as a "ladder" within the existing core ..."

I was talking about the various Ford and GM radiators I've seen tankless. The "rods" I've seen used on those are actually flat bars. Those rectangular tubes on the Behr look the same, at least at the the entrance, and they appear to go straight across. I would be interested to see one cut open.

Did I read this right? You also wrote "Hold the rad up to the light and look through from top to bottom. Where you can see the light at the "end of the tunnel" the rad is blocked."

They're blocked if you CAN see through them!? Or is that a typo? If there's an internal structure in the rectangular tubes I wouldn't expect any light to get through even a clean one. And if you can see light why wouldn't you be able to rod it at least partially? Another reason to dissect one.

I wonder if a detailed flushing and/or a solvent bath could get most of the goop out? Sounds like one of those fun, wet, messy jobs for a hot day.

 

Will it was an obvious typo - my bad - should have been Can't.
The experts say no to your questions.

 

If you are worried about possible electrolysis then distilled water is important; you can see why from the enclosed table.
I have seen it recommended for boats that you can prevent aluminium corrosion with some zinc or magnesium; these are anodic to aluminium and suffer attack themselves.
So maybe throw a chunk of zinc into the expansion tank; big enough so it will not get sucked into the cooling system?

When I took my radiator out last year I gave it a good reverse flushing. After the side tanks were on it was relatively easy to check by eye that there was a good flow of water through it.
I guess you could pour a couple of gallons in and time how long they take to come out to measure the flow through? If we only knew what the flow through should be.

Marton

 

The answer is yes your radiator is ruined.