Residue on radiator cap 2014 Camaro SS

[jgrueningphoto]

Hi guys,

First post here, didn’t find anything exactly like it.

Went to look at a 2014 SS with the L99 yesterday. Garage kept, 25k miles, bill of sale from the local dealer and all except the last services done by the dealer as it’s now out of warranty. 16,500USD too much?

Anyway, here is the real thing. I really liked everything about the car, driving it was awesome, but I can’t shake this picture off. Even though I really wanted to like it. This is the radiator cap.



Ever seen anything like it? I should have touched it, but didn’t. Kinda does look like an oily residue to me, but even if it isn’t - nothing should be in an engine with this little miles, no? The owner claimed dust, but I doubt he had ever opened up the radiator.

Could that be the famous oil cooler leak? Or even the block/head gasket? I’m getting back together with the owner on Monday at a garage of my choice. What test/diagnose will help solve this riddle? I didn’t see any oil leaks/stains, but haven’t had it on a lift yet neither. Is there a way to have a good look inside the coolant reservoir?

I know this is little to go on, but I hope one of you has seen something like it.

Cheers, Julian

[EMB135Driver]

That’s from a lot of short drives where motor doesn't get up to temperature....had the same thing when I lived 2.5 miles from work (30-35 mph whole way too).....when I moved to 8 miles from work (and 30-50 mph) it doesn’t happen anymore.

[jgrueningphoto]

Originally Posted by EMB135Driver

That’s from a lot of short drives where motor doesn't get up to temperature....had the same thing when I lived 2.5 miles from work (30-35 mph whole way too).....when I moved to 8 miles from work (and 30-50 mph) it doesn’t happen anymore.

Thank you for the quick reply. I would have expected that on the oil filler cap maybe, but not the radiator cap... So you used to get that regularly on the radiator cap and once you started driving it more it just vanished? Apparently this car is the families sunday-restaurant-ride, so they do use it little apparently. Did you ever find out what it is or where it comes from?

Edit: if I wipe it off and drive it around for 30 minutes... would it come back?

Thanks again!

[Aqua Blue RS/SS]

Looks like orange dexcool residue to me. Kind of hard to tell from the picture.
Does the coolant overflow reservoir dipstick have oil on it?

[jgrueningphoto]

Originally Posted by Aqua Blue RS/SS

Looks like orange dexcool residue to me. Kind of hard to tell from the picture.
Does the coolant overflow reservoir dipstick have oil on it?

Yeah, I know

Idiot me didn’t think of the dipstick. Would oil stick to that? Would oil be mixed into the coolant turning it milky?

[mikeman]

Looks normal for a car with low miles that never had it's coolant changed. I'm sure there's nothing to worry about. Then again, I have even lower mileage with the original dexcool and my radiator cap looks pristine under it. So, maybe get the compression checked at the very least.

[Aqua Blue RS/SS]

My gut feeling is your fine. If you’ve got chocolate milk in overflow than you’ve got problems.

[jgrueningphoto]

Originally Posted by mikeman

Looks normal for a car with low miles that never had it's coolant changed. I'm sure there's nothing to worry about. Then again, I have even lower mileage with the original dexcool and my radiator cap looks pristine under it. So, maybe get the compression checked at the very least.

Honestly, I’ve never seen anything in my coolant / radiator unless something was off. So unless this dexcool is very different or... I’ll see if I find anything on google about dexcool residue. Cheers for replying

[EMB135Driver]

I wiped it off, and it never came back...not sure what causes it, but haven’t seen it since I’ve been driving further to/from work

[Roamer63]

Dexcool residue. Have it changed.

[dru21281]

Can also be residue from Water Wetter additive. Read it can leave sort of an oily residue floating on top when used...

Sent from my Pixel 2 XL using Tapatalk

[jgrueningphoto]

Originally Posted by EMB135Driver

I wiped it off, and it never came back...not sure what causes it, but haven’t seen it since I’ve been driving further to/from work

So first of all - I am very happy for you haha.

Compression test is one option, but if oil is in the coolant, there must be a leak in the coolant system. External or internal, but there must be one, correct? So why not pressurize the coolant system with one of those pumps to the pressure otherwise held by the rad cap? If pressure is dropping, there’s a leak that lets in oil. If there isn’t... well, oil can’t go through where air can’t. Right?

[EMB135Driver]

Originally Posted by jgrueningphoto

So first of all - I am very happy for you haha.

Compression test is one option, but if oil is in the coolant, there must be a leak in the coolant system. External or internal, but there must be one, correct? So why not pressurize the coolant system with one of those pumps to the pressure otherwise held by the rad cap? If pressure is dropping, there’s a leak that lets in oil. If there isn’t... well, oil can’t go through where air can’t. Right?

Or I could just be content it doesn’t occur anymore, and the car doesn’t use any coolant or oil.....to put context to this the “problem” went away back in 2012 when I moved, and was more prevalent on my F150 than my Camaro.

[CamaroCracka]

I had crap that looked like that in the bottom of my overflow when I did my first cam swap. I was changing to ethyl glycol anyway, so I just cleaned the overflow. There was no oil in the radiator and the oil looked clean, so I just kept going. New cam and turbo later, still beating on it with no issues.