White residue build up in the exhaust tips

[Prez808]

Washed the car recently and then parked it for a week or so and noticed that the exhaust tips have some sort of white residue build up. I have been noticing this for a year or so, but it seems that it is getting worse lately. I had to drive today for about 30 miles round trip, but before I did wipe down the insides of the tips with a damp paper towel. When I came back home, there is more build up again. I have checked the oil and its a nice amber color, but I noticed, the coolant overflow bottle is bone dry. Opening the radiator cap shows a full radiator, with a nice green color. No white smoke coming out of the tail pipe either. I watched the car as it was placed on a dyno for a smog check.

What's going on here?

Tail pipes with about 5 miles on them:



Tail pipes after being wiped off and 30 miles on them:

[wed3k]

looks like the coolant is making its way to your exhaust. when my vw had a blown headgasket, it only smoked on start up but otherwise drove fine as long as i kept putting coolant in it.

[s2cmpugh]

looks like the coolant is making its way to your exhaust. when my vw had a blown headgasket, it only smoked on start up but otherwise drove fine as long as i kept putting coolant in it.

Agreed! Looks like coolant seems to be injested somewhere. If you're losing coolant, then it's either leaking for burning off. Any drips or puddles under the car? Hopefully that burned coolant doesn't clog up the catalytic converter or start to degrade it.

I'd recommend a leak down test and a compression test to be sure. Might as well do a timing belt, balance belt, water pump, etc. too if the head gasket needs to be replaced.

[Prez808]

Well I took the car in for service...

Had a pressure test of the cooling system performed and the coolant was inspected for the presence of hydrocarbons.

Findings: No exterior leaks found. 0 PPM of hydrocarbons found. So no internal leaks either.


I guess I will just observe the level of the overflow reservoir a little more closely and replace my radiator cap with a new one. The existing cap is more than 5 years old and maybe the rubber has hardened a little.

Now what the white residue is, I don't know. Will look at that more closely...

[alan lx]

I have always understood if your tail pipe is a light grey or white, its just a sign that your motor is healthy and burning clean. From what you described, maybe you have more buildup than normal. If its happening more after you wash the car, maybe its mineral deposits? Or not sure about your area but if your area is getting the ethanol in your gas, may have something to with the ethanol. That stuff is not good.

[wed3k]

Had a pressure test of the cooling system performed and the coolant was inspected for the presence of hydrocarbons.

Findings: No exterior leaks found. 0 PPM of hydrocarbons found. So no internal leaks either.


I guess I will just observe the level of the overflow reservoir a little more closely and replace my radiator cap with a new one. The existing cap is more than 5 years old and maybe the rubber has hardened a little.

Now what the white residue is, I don't know. Will look at that more closely...

slow leaks are hard to catch as some will only leak when the engine gets to operating temperature.

[Prez808]

Will just have to observe. No other option really.

[RyanD]

Are those tips aluminum? When aluminum corrodes it gives off a white substance like what you have there

[wed3k]

but he's had that exhaust for as long as i can remember and it's never gotten that yucky. i can understand a little water comes from the exhaust due to the cats but it shouldn't ever corrode that bad.

[deevergote]

Maybe time on the East Coast corrupted the metal?

It's possible that the age of the exhaust is allowing corrosion now, when it didn't happen years ago while it was newer. I know that's been on there for quite some time now.

[RyanD]

corrosion is the only thing i can think of for that problem

[GhostAccord]

I was also going to say aluminum oxide! In that case the tips have to be aluminum. However, I think these are stainless.

What grade and type of fuel are you using? Do you know if they incorporate any type of fuel additive or detergent?

[deevergote]

I wonder if any of the internal parts of the muffler are aluminum...

[Losiracer2]

you definitely have a coolant leak somewhere in your engine. Tail pipes should be black with carbon if anything since that's where all the combustible exhaust gases have to flow out.

Do a leakdown test to confirm its not a headgasket.

FYI, mine went out, started seeping and would cause a stumble upon start up, at 179k miles (F22A6 Auto)

[Prez808]

Still observing and no loss of coolant observed. Tips never got that gunked up again. So strange! There is still a light coat of white residue but much more minimal.

I believe the majority of the muffler is stainless. 10 years old already and no signs of rust.