Black sludge in coolant overflow tank?

So, I took my truck to Jiffy Lube to get my oil changed and the tech asked me to come look in my overflow tank. The tank had some kind of black sludge that looked like motor oil sitting at the top of it. I drained my coolant and filled it back up and it has not re-appeared since. It did not seem like it was motor oil by smell or feel. I am hoping it was just a corroded hose but I know it could also be from the radiator fins degrading and mixing with the tranny. Just checking to see if anyone else has seen this or knows what it might have been. It was on my 4.7 6 speed 05 stepside. I attached some pics aswell.

 

Looks like magnetite. Time for a radiator

Edit: sometimes it can be cleared out by running distilled water through it and flushing it a few times but there is a good chance the internals are good and crusty.

 

Huh. That’s a strange one.

 

Can you give us some history on the truck?

Like….

Timing belt needs to be done at least every 100k/10yr. Radiator can last 125k-150k. Lower balljoints which you never want to install aftermarket, last about 125k. Oil change every 12 months or 5k for Dino and 8k for full synth. What’s the history on your truck?

 

Step 1. Don't take your truck to Jiffy Lube. That looks like used motor oil on that screwdriver.
Step 2. Check your oil for coolant, and do a test on the coolant for products of combustion (will probably be negative, but just for piece of mind)
What exactly did that substance feel and smell like if not oil? And what do the radiator fins and tranny and mixing have to do with this? If you suspect the transmission cooler part of the radiator is compromised, the step 3 is check your transmission fluid too.

 

Ive only had the truck about a year or so and this was only about 8 months into me owning it. From what I have seen on the carfax it had it was pretty regularly serviced all of its life at the dealership. Timing belt and water pump done about 60k ago. Coolant was flushed a few times before I bought it.

 

Jiffy lube is never my first option lol I was just pressed for time. They changed my oil so I didn’t really get to check it. I plan on draining my trans soon to check but I just moved across state to an apartment and all my tools are back home.

 

Huh I haven’t heard of magnetite ever that’s a new one. Looks like it has overheated before from coolant stains I see in the engine bay. Hopefully a new rad is the extent of the issue!

 

That definitely looks like used motor oil and it is weird that it has that color to it considering that when oil mixes with coolant it has more of a sort of milky coffee color. I would definitely do a compression test and test the coolant in the radiator to see if there are any signs of oil as well. Hopefully you find the issue or don't have anymore.

 

It's the metallic crap that builds up from the degradation of the fins, that might just be older radiators, ive never seen it in a modern one.

 

I almost wonder if they poured whatever it is in there to upsell a coolant flush. In fact, I do wonder exactly that. It wouldn't damage anything to put a half a pint of used oil into the overflow reservoir (which sips from the bottom) and it would likely be a slam dunk for additional work.

 

Sounds about right for a quicky lube place. This didn't even cross my mind and they woulda got me, unless I could smell it which would be the giveaway.

 

Something is clearly not right, but the pictures don’t really do justice here to see what happened. This is 100% not anything from your transmission, ATF is pink, not black. And your coolant should be pink long life, also. If not, that’s another problem to deal with. Pink + pink = pink. And the two mixing would be foamy, hence the “pink milkshake” nickname.

First things first, I wouldn’t drive it until pulling the overflow tank, cleaning it out fully, or better yet, replace it with Dorman’s repop of the OEM. Your truck should Refill with long life Then monitor it yourself. It sounds like you maybe already done that.

Secondly, never trust chain stores. Especially not for a job you can easily do yourself, better, using better parts, and still paying less. The original owner of my 2006, which currently has 80k original miles, used a specific Jiffy Lube chain store in the Birmingham AL area for his regular oil changes. ~8k miles after I got the truck, when I had to do the valve covers, the heads looked like absolute dogshit, like someone sprayed wood varnish all over them, and traces of sludge. There are links to pics of this in the “low mileage warning” area near the top of the community megathread.

Anyway, with the traces of stain in the filler neck, I’m wondering if someone didn’t pour something in there. And given my local dealerships typically are as cheap-as or cheaper-than most Jiffy Lubes, I’d probably hit them up to do my oil if you insist you cannot. But if you want to start doing your own oil on your 1st gen, seriously, hit us up in the Lunch Table thread. No judgment from anyone here, we’re not gonna give you hell for learning, wanting to do more. It’s something everyone should know how to do.

Whatever you do, I wouldn’t go back to that store, there’s some fuckery happening. And if you’re worried about the integrity of the engine, do a compression and leak down test.

Let me ask you this: How many miles on your truck? Have you ever overheated in your truck?

 

Keep us posted as I for one would like to know what the final outcome on this ends up being.

 

They told me they thought it was my headgasket actually. I thought the same thing but they told me to go see a real mechanic.

 

She’s sitting at 160k. I see signs of dried coolant in the bay and it runs hot so I’m assuming it’s had overheating issues before. I plan on putting a new rad in soon I’m just waiting to go back home where my tools are.

 

It'd be highly unusual, if you've never overheated and are using the correct coolant, and replacing the coolant every 100k or so.

But a compression and leakdown test would answer that for you real quick.

 

Dried coolant crusties in the engine bay isn't unheard of.

 

Did you ever get this figured? My guess was head gasket. Sure looks like motor oil.

P.s. is weed legal in your state? Maybe the Jiffy tech mistook the coolant reservoir for the oil fill cap

 

First thing I'd do is remove the radiator cap and see what the coolant looks like in the radiator. And post a pic. Then check the oil level, and post a pic of the oil on the dipstick.

I thought the same thing as the earlier post: that the tech dumped used motor oil in there. But you're saying they didn't try to upsell you, so I don't know what the motivation would be?

 

Maybe they have an automated alert setup on FB Marketplace and Craigslist for "2005 Tundra" and are waiting for OP to panic and list it for sale with a blown head gasket.

 

Hopping in on the convo for a similar issue. There is no oil in the reservoir, but it is going through coolant like an MF. I have to top off every day. I do not believe I have a presence of motor oil. Everything is still pink but losing coolant fast. A hose, more than likely? Is the easiest way to test a compression test?

 

I chased my tail on this for a my hot minute, ended up fixing it with a new radiator cap. Might be worth the $5 to start there.

 

First, check for leaking coolant on the ground under the truck. Then check the transmission fluid level. You have a 2005, so you don't have a dipstick. To check the fluid level, start the engine and let it idle, then crawl under and remove the fluid level plug. Instructions attached.

 

"Losing coolant fast", are you seeing any residual coolant anywhere? Any signs of pink/cloudy spatter anywhere inside the engine bay?

Small leaks in radiators often won't present themselves unless you're pushing water through the engine (i.e. holding the accelerator at higher RPMs). I wish I could find the two threads I pointed this out to others with, and helped them find their leak by revving high and looking at the radiator.

Got a cinder block or large rock or a 2x4, anything you can wedge under the pedal and get the RPMs up to, like, 2,500 RPM, then go look under the hood, OR have a friend gun the gas for 3-5 seconds at a time to hit that RPM while you watch the radiator, preferrably while the engine is already up to operating temp? Common leak spots are where the top/bottom cap meet the metal part of the radiator, and in the radiator fins themselves, keep a close eye anywhere you see a dent, sometimes a rock thrown on the interstate will hammer one of the tiny coolant tubes.

Megathread also contains info on the other common leak spots: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

• Coolant leaks: Three common causes: One is the is the gasket behind the thermostat housing, another is the coolant crossover at the rear of the block, and last but not least, old radiators is another source. Here's a list of things to check if you're losing coolant. For repairing the leak behind the t-stat housing, check this out. For the coolant crossover tube issue, you'll likely find coolant at back of the block, near where the trans and engine meet, check this reply for video/fix. This post is for leaks at t-stat housing/inlet neck. This reply contains links to three other off-brand/odbball leak cases. For radiator leaks, this is one example of a tiny one - always replace with Denso brand radiator, and know different cab types use different sizes, careful where you order, scAmazon especially tends to deliver damaged products often (RockAuto has a spotless record with forum members). Proactive radiator replacement is wise. The transmission line routes through the bottom of the radiator ... go look up "pink milkshake", it happens in these trucks.

 

seeing cloudy splatter in the bay, below battery tray on frame and what not. Yesterday, Driver front rim was all wet, looked under and cv, brakes, were wet. Wasnt oil or diff. Didnt smell like gear oil or anything like that nor the oil consistency.