'05 CDI- Is one row radiator adequite? - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 06-13-2018, 08:32 PM

I needed to replace the radiator in my brothers '05 E320 CDI W211, so I ordered and received a Spectra Premium unit. To my surprise, it has only one row of tubes. The factory one had two. I can't see how manufacturers can sell a radiator with half the cooling capacity. The description says "Unit is designed to original equipment (OE) fit, form and function requirement".
It looks identical, so it should fit just fine. It is the "function" aspect I am concerned about. I just wonder if I should send it back and get a two row (Nissens or Valeo).....Rich

BillGrissom · #2 06-13-2018, 10:07 PM

It wouldn't have half the cooling. Even if the 2-row gave exactly twice as many identical tubes, it would only give ~30% more cooling, since the front tubes see cooler air. What matters more is the thickness of the core in each. I think there are 1-row radiators which are as thick as a 2-row, so almost the same tube surface area, and perhaps less coolant flow resistance. Heat xfer to the air is limited more by the fin surface area than the tubes. Not sure, but I think many aluminum radiators have fewer rows, or even 1 row, yet they generally cool better than copper.

mbolton1990 · #3 06-13-2018, 10:10 PM

Dunno if I'd trust a Spectra rad in a CDI. That's a real nice car and a real important part to go cheap on. Just food for thought

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Mxfrank · #4 06-13-2018, 11:03 PM

Quote:

Originally Posted by ROLLGUY

I needed to replace the radiator in my brothers '05 E320 CDI W211, so I ordered and received a Spectra Premium unit. To my surprise, it has only one row of tubes. The factory one had two. I can't see how manufacturers can sell a radiator with half the cooling capacity. The description says "Unit is designed to original equipment (OE) fit, form and function requirement".
It looks identical, so it should fit just fine. It is the "function" aspect I am concerned about. I just wonder if I should send it back and get a two row (Nissens or Valeo).....Rich

There's a lot of crap out there, but your assumptions are bad. The question isn't only the number of tubes, it's the size of the tubes as well. And fin design makes a big difference. Some of the worst radiators have four or more tubes and very dense rows. More is not necessarily better. Unfortunately, the only way to know is to try it.

What's important is how much tube/fin contact area is created, how restrictive the air flow path is and how turbulent the air and water flow are. Lately, I've been competing against insanely cheap Chinese radiators which invariably come with four small rows. My radiators have two rows. But in a comparison between four 3/8" tubes and two 1" tubes, the 1" tubes give measurably bettter performance. See the drawing below to understand how fewer can be better. The problem is that the ends of the tubes make poor contact with the fins. So fewer, bigger tubes have more contact area. It may seem to be a small point, but it makes a big difference. Additional improvements can come from corrugated fins and turbulators in the tubes.

ROLLGUY · #5 06-14-2018, 12:16 AM

The S.P. radiator has literally 1/2 the fins/tubes as the stock (Valeo) radiator. The tube count and width is the same, but one row vs two. Again, I can't understand why any vendor could even sell these. Could it be that my car has some sort of "extreme" cooling package, and the "standard" cooling package has a one row rad from the factory? Maybe the one row would work just fine? The reviews on the site were positive for this particular radiator.

vstech · #6 06-14-2018, 07:56 AM

Nissans, or stock...

Mxfrank · #7 06-14-2018, 08:40 AM

Quote:

Originally Posted by ROLLGUY

The S.P. radiator has literally 1/2 the fins/tubes as the stock (Valeo) radiator. The tube count and width is the same, but one row vs two. Again, I can't understand why any vendor could even sell these. Could it be that my car has some sort of "extreme" cooling package, and the "standard" cooling package has a one row rad from the factory? Maybe the one row would work just fine? The reviews on the site were positive for this particular radiator.

I think there's some confusion here. If "the tube count and width" is the same, then the radiator would have the same number of rows. If the overall thickness is the same, but half the number of rows, then the tubes are twice the width of stock. In that case, it's perfectly plausible that the radiator would cool at least as well as stock. Also, I don't see any spec on fin count or fin width for the SP radiator, what are you looking at?

Here are two radiator cores, not necessarily for your application, to illustrate the difference between a one and two row core.

DieselPaul · #8 06-14-2018, 11:20 AM

With as clearly in doubt as you are, I'd return it.

You've been given some solid info from MXFrank, but at the end of the day it is your car and if you're not comfortable you should NOT run the part.

ROLLGUY · #9 06-14-2018, 11:56 AM

Quote:

Originally Posted by Mxfrank

I think there's some confusion here. If "the tube count and width" is the same, then the radiator would have the same number of rows. If the overall thickness is the same, but half the number of rows, then the tubes are twice the width of stock. In that case, it's perfectly plausible that the radiator would cool at least as well as stock. Also, I don't see any spec on fin count or fin width for the SP radiator, what are you looking at?

Here are two radiator cores, not necessarily for your application, to illustrate the difference between a one and two row core.

No confusion here. I originally thought that the one row S.P. radiator would come with wide tubes like your illustration, but in fact it is not that way. The two row is basically two of the one row cores together. Same amount and size of tubes. A little more research has revealed that the one row rad is for the gasser, not the Diesel. All the vendors on the web show that the single row rad will FIT ("drop in replacement") the CDI. I have decided to send the rad back and ordered a 2 row from 1-800 RADIATOR through my local radiator/A/C shop that I work with all the time. It will be here this afternoon. It is only a few dollars more (because of the tax) than the Rock, and I will get it today.

DieselPaul · #10 06-14-2018, 12:04 PM

Good info, thanks for posting the resolution

BillGrissom · #11 06-14-2018, 10:42 PM

Thanks for the clarification. Others may not relate to your climate, assuming your brother lives in the Mojave Desert like you, or at least visits since all it takes is 1-time of over-heating. Inland regions in CA often reach 115 F on summer afternoons, and you get no points for "low humidity" in radiator heat transfer.

ROLLGUY · #12 06-14-2018, 11:09 PM

Quote:

Originally Posted by BillGrissom

Thanks for the clarification. Others may not relate to your climate, assuming your brother lives in the Mojave Desert like you, or at least visits since all it takes is 1-time of over-heating. Inland regions in CA often reach 115 F on summer afternoons, and you get no points for "low humidity" in radiator heat transfer.

I think regardless of climate, the CDI needs the two row radiator. If it was just a regular E320 (gas), the one row radiator might have been adequate.

ROLLGUY · #13 06-17-2018, 11:23 AM

I got the two row radiator and installed it. Everything is working great!