Need experts' advice on whether a radiator can be used
 

Car: '89 928 S4 Auto with ~100k miles

Hi, everyone. I don't post very often, but I hope you may still help me. I'd really appreciate it. I recently bought a radiator from the classifieds section here. My plastic end tank cracked and I wanted an OEM part if I could vs. aftermarket. I found one that was described as being in good condition, flushed, and pressure tested. However, when I inspected it, the inside of the oil cooler was coated in chocolate milk. You can put your pinky in and it comes out with slimy chocolate milk oil.

I paid $550 for it shipped; which is the going rate for a ready to drop in used unit. He is saying that it isn't his fault because the contamination probably happened when the shop he paid to flush and test it put the unit in a tub of water and coolant. He also says that it is my fault because I didn't ask for enough pictures.

I don't feel comfortable just flushing out the oil cooler with degreaser/brake cleaner/etc. and hoping there isn't anything left that will cause contamination and engine damage. I've looked through the forums about what to do when you have this kind of contamination in an oil cooler. Most professionals and folks on here say you should send it off and have it ultrasonically cleaned to be sure. However, that isn't practical here because I'd need to take the end tank off and then reassemble.

I want to send it back and buy another that is ready to use. The seller won't budge. I've taken it to Paypal. They want to see expert or unbiased third party opinion that it wasn't delivered as described; which in this case is working condition, flushed, and pressure tested. To me, that means I can put it in and use it without any extra work. I'd love to hear your opinions on this. Perhaps I am wrong.

Thank you for your time,
Raymond

Use a couple of cans of BrakeKleen to clean it out, bring it to a reputable radiator shop to be pressure tested. If it tests ok use it.

If the radiator was in the condition you describe then clearly it was not in "working condition". It was the vendor's responsibility to ensure that when the unit was returned from the shop that "tested it" that it is was clean and that no such gunge was obviously present. A good shop would never let such circumstance happen and perhaps what you have seen is not shop test residue rather it is a failed cooler core. Under normal circumstances when the motor is running the oil pressure is hotter than the cooling water circuit and if there is a breach the oil will preferentially flow into the coolant. However, when one shuts the motor down the oil pressure collapses almost immediately whereas the cooling circuit holds pressure for some time as it gradually loses heat to the surrounds.

If you have not done so you might consider challenging the vendor to provide you with the name of the shop that tested it and ask for evidence [a test certificate?] or a contact person who can verify this testing actually happened.

When testing a radiator for leaks the matrix is typically pneumatically tested to its design pressure [15 psig] and immersed in a tub of water to identify any leaks- the end tanks should of course be plugged whilst this happens. They could of course forget to do this but most unlikely I would suggest and if they did they should clean up the mess. Flushing out the coil with diesel is not too hard a task to do.

What perhaps you should do is to subject the oil cooler [not the radiator!] to a pneumatic pressure test at say 8 barg [max oil system pressure] to see if it actually holds such pressure. If it does not then it would be obvious that you have been well and truly screwed over and that should strengthen your case with Paypal conclusively.

Do as the others recommend, and flush the coolers. The innards are aluminum, so it's very safe to clean it with a bit of laundry detergent and hot water. After that, pressure test the coolers to verify that they are leak-free.

Used radiators typically get basic cleaning and pressure testing of the coolant side, while only some may get the coolers tested. Finding slime in the coolers can be the result of a head gasket failure, or there was residual oil in the coolers when the coolant side was tested. Typical test method is plugs in the coolant nozzles, compressed air to the 1bar cap relief pressure, and dunk the radiator in a water bath to look for bubbles. If there's residual ATF or oil in the aux coolers, they may end up as the milkshake consistency you report from the exposure to the water/coolant/etc in the test tank.

FWIW, the coolers themselves are quite robust, with damage happening more from connector abuse than anything else. This might be from removal when someone doesn't counterhold the cooler fitting while disconnecting a hose. There are o-rings that seal the cooler fittings in the plastic tank.

The most common radiator failure mode is the cracking on the end tanks (specifically the right/passenger side on US cars) that you report. Our favorite vendors offer replacement tanks with seals. Any competent radiator shop should be able to change them for you and test the radiator and coolers for you. This is generally a lot cheaper than replacing your radiator with a used one, especially if the used replacement still has the 20+yo original end tanks. If your original radiator has enjoyed regular coolant changes through its life and no physical abuse, just replacing both your end tanks makes a whole lot of sense, IMHO.

I'm living dangerously with the original radiator with original tanks, but have a whole spare new-in-box Behr radiator in the spares pile "just in case". Considering the market for the pieces, I'd as soon put new tanks on the original when they fail, vs. installing the new spare. I get to keep all the original stickers and such.

Last thought: Get new support rubbers for whatever radiator you put back in. The originals are hard and don't allow the radiator to flex as the car twists and the radiator changes shape in normal use (thermal expansion...). Resist the temptation to adjust the support brackets for a tight fit; You just need to keep it from falling out of the car.

Advertised as "flushed", obviously was not. Don't see what the deal is with sending it back and reverse the payment. Take a pic of the goo that is in the cooler, and be done with them.

Who was the seller so we may avoid dealing with this person.

Sounds like a very poor quality seller if he claims this is somehow your fault.

I suspect that the effort and aggravation involved in returning the radiator will vastly exceed the effort and aggravation of flushing the coolers with laundry detergent and the garden hose. As interesting as it might be to somehow "make thing right" with a misrepresentation from the seller, the fix to that misrepresentation is taken care of with ten minutes of work, a few ounces of liquid Tide, and a bucket. Focus on the goal of getting the car back together and running with least available effort and aggravation.

My too sense...

Thank you all so much for your time and feedback. Here is the link to the original for sale thread:

https://rennlist.com/forums/parts-ma...-radiator.html

Paypal is wanting:
"Please provide a copy of an expert's or unbiased third party's description as to how the item is not as described."

Do you all have any advice on that? Would you be willing to be an "expert or unbiased third party"?

Here are some links to pics and video. Please ignore my comments on the cooler being ruptured. It was just a guess. I am wondering about how the fins closest to the opening seem to be somehow bent. My radiator that I took off isn't like that. Thoughts?

https://drive.google.com/drive/folde...mjwuEuZmUKb_o3

Thank you so much!
Raymond

This is sad and makes me mad. It only paints a black eye on the best internet forum for car enthusiast!

Send me some pictures.

I'd gladly look at them and try to be an "expert". I know a little bit about these cars.

GregBBRD@aol.com.

The best advice is what Dr Bob said. Wash, rinse, repeat, and move on. The rest of us take note about the seller.

Thank you for the help everyone! Emails sent.

If Paypal doesn't come through and I am stuck with this one, is rinsing it out with brake cleaner and detergent enough to be safe if I don't know for sure why it is that way? If it was like that because the original source car blew a motor or head gasket (it's from a Chevy motor swap car), would that be enough to not have to worry about metal particulates and other nastiness? Do the bent fins when you look through the fitting neck look okay? Why/how do you think they would get like that?

Thanks!