expensive cleaning mistake, plastic intake dissolves.

[pjtoledo]

cleaning the carbon and oil inside the runners of a 2.3 Duratec intake. 367,500+ miles and used a LOT of oil in cylinder # 1.
there was about a 1/2" puddle of black gooey mud in the top chamber before the runners.
started with oven cleaner, got some out with no damage. can't get up into the runners.
switched to Draino, got more out, still left a rough coating, no damage after 6 hours soaking.
the crud inside is now white, I'm determined to get it all out.
using a bore scope I can still see crud up in the runners.

poured in some muratic acid , it comes in a #2 plastic bottle, it must be safe on the plastic intake , right???

let it soak overnight, apparently the intake isn't genuine plastic. metal nut inserts sure are clean. plastic tub is OK.
the big plies of gray stuff are the result of about 2 lbs of baking soda neutralizing the acid.

word of caution, hold your breath when using concentrated acid. if I wasn't bald I'd be a blonde now.

 

[superj]

Whoa, that sucks that it melted your intake

 

[Roert42]

Good excuse to buy a fancy new intake?

 

[Curious Hound]

There are a lot of different types of "plastic". Obviously, that one is different from the bottle your acid came in.

 

[85_Ranger4x4]

We use murattic acid to ruthlessly strip anything/everything out of old fuel tanks.

It is super nasty crap.

 

[Bill]

Most "plastic" intake manifolds are made with nylon/polymides and other poly-things. Some have a combination of other materials like fiberglass or ceramic resin injected into a mold. All the materials are compatible with petroleum products. Not so much with anything that causes oxidation. The process you just experienced is called hydrolysis.

I've seen videos of people cleaning them with brake cleaner and mineral spirits without any problems. There's a video on youtube where someone left oven cleaner on a valve cover (made from the same material). It didn't melt through the valve cover, but it caused enough damage to the gasket mating surface that it made the valve cover useless.

Out of curiosity I attempted to look up the price on Rockauto. They aren't listed. They had three brands for both intakes (2001-2003, and 2004-2011). They are no longer listed. Dorman was one of the brands and they no longer have them on their website either. It was only about a week ago that I saw them listed. It's probably another COVID supply chain issue. But, it appears both of them are available new if you search for them on Google.

1L5Z-9424-A and 4L5Z-9424-AJ.

And a nylon chemical compatibility chart.

Nylon Chemical Compatibility Chart

www.calpaclab.com

 

[pjtoledo]

the runners were up side down compared to the pics. the runners pointed up so pouring liquid into them filled the entire runner.
so this damage was from the inside. I had observed the acid for 3-4 hours and didn't see any bubbling so I thought all was OK.


overnight it failed and acid flowed out to form a shallow puddle in the container which damaged the outside of the other runners.
only two runners had the acid in them.

this was supposed to be a temporary engine so I'll either modify a 2002 manifold or get a used 2005.
Ford has new listed as backordered.

before this I got lots of gunk out with oven cleaner, but it left a film of crusty stuff.
then Draino, it got more out but there was still crusty stuff where I couldn't get a brush.
then vinegar, the 4% cooking stuff. not much effect on the crusty stuff.
then Simple Green. by now the film was white and still around the curve where I couldn't reach.
last was the acid. I haven't looked yet to see if the crusty stuff is gone.

thoroughly rinsed between all concoctions.

I'm going to try a repair, have to find some glue or remover that will soften the material for a patch.
maybe...


EDIT: found more holes, it's too damaged to repair.

 

[pjtoledo]

There are a lot of different types of "plastic". Obviously, that one is different from the bottle your acid came in.

bottle was plain 'ol #2

 

[pjtoledo]

We use murattic acid to ruthlessly strip anything/everything out of old fuel tanks.

It is super nasty crap.

this was 31% acid
what do you neutralize it with?

that pile of gray stuff surprised me as it started forming while I stirred in the baking soda.

 

[DILLARD000]

Wife is OCD about clean floors in the house...
I'm afraid she's going to do something like this & destroy the place!

 

[lil_Blue_Ford]

Whoa… I knew that not all plastics and chemicals were compatible but yikes!

This also reminds me, I need to clean the intakes for my 5.0, but they are aluminum. I have been scratching my head on exactly what to use though, I don’t see any good way to scrub the runners in the upper intake

 

[Bill]

Whoa… I knew that not all plastics and chemicals were compatible but yikes!

This also reminds me, I need to clean the intakes for my 5.0, but they are aluminum. I have been scratching my head on exactly what to use though, I don’t see any good way to scrub the runners in the upper intake

There are degreasers that are safe for aluminum. Depending on the degreaser, it may or may not work well if it is carbon that you are trying to get off. You can also try soaking it in a strong detergent set it out in the sun. I've had decent success with Dawn detergent, baking soda, and scrubbing with a stiff nylon/plastic brush. Then there is mineral spirits, which is good for breaking down grease. Maybe use mineral spirits first, then scrub it with detergent and baking soda if it isn't clean enough after using mineral spirits.

 

[dvdswan]

What did it do to your hands and rags?

 

[pjtoledo]

I was wearing nitrile gloves and taking care not to get any acid on me. didn't get a chance to use rags.

FYI: when using the "good" paint strippers nitrile gloves soften fast and you can feel the burn before they rupture, so change gloves often.

 

[pjtoledo]

picked up a used manifold today.
now I have spare:
throttle body
tps sensor
IAC
manifold pressure sender
PCV/coolant connector
plus a couple clamps

got my monies worth