Hello everyone! I have a leaking ECP radiator. This is the second one they sent me under warranty. Also, I have a third, brand new and warrantied unit(they didn't ask for the second one back and is still in the car) sitting on the shelf which I have decided not to install as I feel it will just leak again. The leak came from within the fins on both occasions. In this adventure I replaced the entire cooling system assuming I was the one doing a poor job just to rule that out as the original leak worsened, revealing the source. On top of both units performed worse than the OEM unit it replaced, so I am not exactly incentivized... and weirdly the second one was about an ~inch too short, it does not seat in the upper mount properly

The car is a 2000 M6 with 135k. It is a daily driver and will never see the track. However, I will eventually rebuild the engine, port and polish the heads, valves, etc... and install a street-able cam in the process. I'm thinking it will max out at ~400-425 rwhp if I'm lucky? I don't have experience building motors yet, so maybe one of you more experienced chaps will chime in on that.

The current mods that affect power are a Z06 intake and LT headers and 3 inch exhaust.

I am considering a DeWitts with the integrated oil cooler and maybe the SPAL fan upgrade. It won't see race conditions but I am in Texas and we do see up to 105 degrees days. If I am stuck in traffic the hottest the oil ever gets is 230 and usually hovers between 200-210. So maybe the oil cooler adds unnecessary complexity. Currently the AC struggles to stay cold while in traffic; this was not the case with the OEM radiator. I assume the ECP unit is more restrictive. Would the DeWitts have a similar effect and need the fan upgrade?

From what I gather from a few threads is that a stock car doesn't need the upgraded radiator or fans and the oil cooler is over kill, but I need to make the best long-term decision I can. I want the car and all of it's components to stay in the best shape possible and heat is the enemy. So maybe GM has decided that the stock radiator is 'good enough' but is it good enough for a car that will be in the family for perhaps a few generations?

Any advice is appreciated and thank you for reading.

 

I too just got bit by ECP quality, leaking from the fins. Only lasted maybe 10k miles? At least for me, it came with the car, and it was not a purchase I made on my own.

It depends on use case, if you're truly using this as a daily and not going to track it, I'd be inclined to just put an OEM radiator in it. It'll be fine, even in the TX heat.

The only other quality alternatives are a Dewitts, LG, Ron Davis, C&R. All in the same ballpark for pricing. And no, you don't need an oil cooler for a street car, there's no need for an extra fail point.

I just replaced my ECP with a C&R. The quality of the C&R makes the ECP feel like a Pepsi can. It's got a few pounds on it for sure.

 

Dewitt's has a sale going on right now! 12% off if I remember their flyer correctly. That's what I am running and it is a fine piece!

 

There are many of us with leak free 20+ year old stock radiators. 105 degree ambient is not at all unusual.

 

 

Dewitts is nice. However, I would run an extrenal oil cooler with an Improved racing thermostat on the adapter to connect the line. I'd rather not have the oil heat soaking the coolant. A prior owner installed a radiator with an integrated oil cooler in my car.

LPE, Doug Rippie, and Improved all offer oil cooler kits. I'd likely go with Rippie lines and cooler with the Improved adapter. Randy Rippie will sell the parts for the oil cooler individually. Improved stuff is likely the most cleanly engineered but expensive.

https://www.improvedracing.com/low-p...s-engines.html
https://www.dougrippie.com/c5-corvet...il-cooler-race

It also looks like Rippie is an Improved Dealer. So you maybe able to order the oil cooler parts in one place.

 

I have an ECP radiator and have not had any issue, as of yet (feverously knockings on wood as I type this).

I high recommend a true oil cooler kit, not an oil heat equalizer exchanger built into the side tank of a radiator. Due the bearing clearances, my specific engine requires 15w-50 oil all the time, so it needs a 200 or 212 degree thermostatic adapter for the oil cooler. The engine coolant likes the 180 degree thermostat. Secret to making power is lower coolant temperature and keeping the oil it its optimum temperature, which can be higher than the coolant with heavier weight oils.

I installed the Improved Racing oil cooler kit on my '99 FRC. It is a top notch kit, highest quality I have seen. I found a couple differences on my car due to the mounting bracket for the ABS and the cooler line routing. I sent the info with pictures to Michael at Improved Racing, since I think the development work and installation instructions were done on '01-04 cars. The Improved Racing kit was proven on Spec Corvette race cars, before being offer for sale to the public. Plus it adds over 2 extra quarts to the oil sump capacity. I have had folks mistake the huge MHX248 oil cooler for an intercooler

 

I have a DeWitts without the oil cooler. My coolant temps are find here in North Carolina summers.

I do notice oil temps creep up a little when cruising in a lower gear. For example, cruising at 50 mph in 6th gear will result in lower oil temps than 5th gear. Something about higher engine speed causes the oil temp to increase. If dropping down to 4th gear the oil temps will creep up to 226 degrees on a 70 degree day. But the same 50 mph cruise in 6th gear will be closer to 212 degrees (after reaching steady state).

 

I put a DeWitts radiator with both engine and transmission coolers in my 2001 A4 in September 2013, plus Improved racing oil thermostat and hoses. No leaks in ten years, 22 more days on road course tracks, 35,000 more miles.

In my view if you are not tracking the car you do not need an oil cooler or special fans, but a DeWitts is a good idea.

 

I have a stock rad in my built Z and no issues. AC brrrrsky and engine stays close to the 180F t-stat tempt even when 100+ outside. I do not track it though. I think the OE setup is pretty good.

 

IMNSHO, I think the Corvette power train engineers should be ashamed of themselves for not including an oil cooler setup from the factory on the C5, doubly so with the Z06.

 

When you look at the large group of aluminum radiator companies out there, DeWitts is the only one that actually manufactures the cores in house and uses stamped formed end tanks. Most of the others, are just assemblers, and they purchase their cores from China or Mexico without any knowledge or control over how the core was made

 

Has anyone bought a GM OEM replacement radiator recently and noticed the manufacturing location? I am curious if they are still manufactured in Lockport NY by the former Harrison Radiator/Delphi Harrison Thermal which is now the GM Lockport Operations.

 

I went with Dewitt's to avoid the high engine temps when I have to drive in Dallas in the summertime. It's perfect and easy to install. Makes the oem rad look like a toy. I dont think you need the fans or the oil cooler.

VS

 

I don't see the OEM GM radiators listed for ATs on Rock Auto just MT. Are they not available any more?

 

Summit Racing looks to have some options including AC Delco but they ship directly to the customer so, you may want to call to get the delivery time.

 

The GM Genuine Parts 20889 Radiator is available and applies to the AT and MT 1997-2004 C5’s.

 

Thanks will check it out.

 

I have a brand new, in the box GM 52540606 radiator in the garage (and on the parts for sale forum). It was made, as sadly anticipated, in china. The order form, box, and label all say 52540606, but the radiator is actually a Delco 20889, complete with transmission cooler and 5/8-18 cooler fittings. The cooler and fittings make the 20889 suitable for all manuals and a direct fit for slush boxes up to 2001 (or maybe 2002?), when they switched to quick disconnects.