PO Clearcoated the Engine / Bay

nmwhitneyjr

nmwhitneyjr

New member
At some point in my car`s past, the PO had the engine bay detailed and then shellacked or clear coated. No surprise that now 60% of that has flaked off and the rest has turned a dirty brown color. I degreased the engine. That helped some, but what remains acts like it won`t come off with a diamond-tipped drill. Any advice on how to get the rest of this off?
 
Short of sandblasting or hand wet-sanding, no, cured clear coat will not come off easily. If it is shellac, mineral spirits MAY work, but will risk getting that on rubber hoses or plastic that may degrade them significantly.

Depending on the severity of flaking on which engine parts (intake manifold or valve covers), it may necessitate removal of these items from the engine to properly and completely "clean" them of whatever coating is now degraded to the point as you have examined.

Are you sure it`s not aftermarket undercoating that may have been dealer-applied??? This will also flake off when a vehicle has seen many years of service. You also failed to mention the car`s manufacturer, vehicle model, and model year it was made. Is the engine a V8 or a 4-cylinder? Not that it matters, UNLESS you are going to remove these engine parts yourself. If it`s a Jaguar, Mercedes, or other hi-end car, you may feel slightly intimidated, depending on your mechanical prowess and experience.
 
Could be cosmoline from a rust proofing package that has been attempted to be cleaned off in the past with previous details.


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nmwhitneyjr- What have you tried so far?

How do regular prep-type solvents work?

What about lacquer thinner (be careful what you get it on)?

And yeah...what car? I gather you`re certain about it being some clearcoat sprayed on by the PO, right?
 
Im pretty sure he is talking about his new car, the Mercedes in his avatar.
He first posted up this Mercedes talking about its history, etc...

NMWhitney Jr, have you tried degreasing AND pressure washing the degreaser off ???
Just make sure you dont wet things that will make it hard to start later, etc..

I always pressure wash engine compartments but know enough to not get into trouble, and then blow out all air with my Master Blaster 8hp blower, and leave the hood open all day long to help dry what may be left in there..

Sometimes, I even (if its cold like in fall, winter) bring it inside and open the hood again and leave it that way all night, to further insure its as dry as possible, before I treat all the plastics, etc..

I remember way back when I was a kid, that some shops would steam clean engines and spray something on them to make it all shiny - bet it`s what happened to your Mercedes..
Dan F
 
Stokdgs said:
I remember way back when I was a kid, that some shops would steam clean engines and spray something on them to make it all shiny - bet it`s what happened to your Mercedes..
Dan F
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Correct on nearly all points Stokdgs... the "spray something on them to make it all shiny" is the stuff I`m talking about. With it flaking off, it looks like my engine & bay has psoriasis.

I degreased but only used an open hose to rinse. I used a soft, plastic bristle brush on some of the larger (easier to reach) areas. What`s left is bonded pretty well to the valve cover, linkages and even the hoses. It`s a mess.

I didn`t pressure wash as there are soooo many vac hoses, linkages, nooks and crannies in the OM602 engine. Simply too much opportunity to knock something loose. I`ll post a pic tomorrow and you`ll see what I mean.

... and yes, this is the 1991 Mercedes 300D 2.5 Turbo.
 
Guilty of using that junk in the 90’s at my dad’s car lot. After seeing the results months later I stopped using it. I only used it on older usually high mileage cars. It is really like a cheap clear coat spray paint.
 
Oh yeah, that wonderful `91!

I`d be trying pre-paint prep solvents instead of degreasers, which I only use on, well...greasy messes that need emulsified.

I don`t suppose the hoses need replaced? Simple but expensive solution to that part of it.

This is the kind of dilemma that`s kept me away from products like Motor Kote.
 
Nmwhitneyjr. --

Well, that looks like a real Detailer`s challenge in that engine compartment !

If it was lacquer sprayed on the engine, then lacquer thinner should loosen it up, and since there are fast-dry and slow-dry lacquer thinners, you can choose what you think may work best for you if you go that route..

When I mentioned pressure washing, I meant using something strong enough first to get all the stuff loose so that you would not have to hold the pressure washer tip that close to blow it all off. When I pressure wash anything, I always use a wide fan tip, so there will less chance of accidentally damaging the worked areas..

I can only think of one other thing that might work because I saw them do this in the Shop where I did Detailing before..
They use ground up walnut shells to clean out carbon of BMW intakes sometimes, and it really knocks out the carbon without harming the metal..

Might have to do research on what type of gun they use and see if that is an alternative ...

i know some people use sand or a grit to do body cleaning etc., I just don`t know if those types of media would change the finish of the metal and plastic parts of that beautiful engine or not...

Good luck with this - hope you get it looking like it did when it was built back then..
Dan F
 
If lacquer thinner doesn`t do it, I`d wonder about *very carefully* using a stripping product. Well, depending on what the finish underneath that [stuff] is..

There are all sorts of blast medias these days, but I`d only do it after a thorough disassembly, which would sure be an undertaking and I gather that`s not in the cards.
 
Still looks like cosmoline to me. Was common on those engines. They make cosmoline remover. Some oven cleaners work too. Diesel fuel works well too and it’s non volatile. Wurth Engine cleaner and degreaser does too


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MattPersman said:
Still looks like cosmoline to me. Was common on those engines. They make cosmoline remover. Some oven cleaners work too. Diesel fuel works well too and it’s non volatile. Wurth Engine cleaner and degreaser does too


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Click to expand...

Here’s another one this is a 1991
6090b5634a8e0bb9db89a91d5cbf012d.jpg



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Mattpersman- That may well be it. We`d always cleaned it off the obvious places before it got nasty, didn`t even occur to me even after you suggested it!

I guess the reason why it didn`t register with me was that mnwhitneyjr is having so much trouble getting it off. I always found it comes off easily enough (especially with some applied heat), but maybe that`s because mine wasn`t too old/baked on. The real challenge was always cleaning it up without cleaning it *off*, lots of products make it look milky/cloudy, including the degreasers I tried.

Is your Remover the, uhm...official Cosmoline brand Cosmoline Remover? Either way, I`m curious about any benefits compared to regular solvents.
 
MattPersman- Ah, yeah. If somebody`s buying such stuff I`d sure like to see them get the business so I`m glad you posted that.

Hopefully we`ll soon know whether it *is* that and whether it cleaned off OK.

I`m wracking my brain trying to remember cleaning it off something *really* old/baked-on, but every time I`ve tackled such stuff it was so easy that I guess my experiences just aren`t in the same league. Some aluminum bits did stay discolored though..but even for a top-flight Concours I`d think such imperfection is just how-it-was-built.
 
One thing about cosmoline it sure protects. It just looks like hell when over the years people have tried to detail the car and leave patches on the engine like the OP has


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I had a similar situation with my `87 El Camino I bought in 1993. There was a thin amber-tinted coating over the entire engine, inner fenders and core support. When I decided to get serious about removal, I tried every solvent I could think of except for lacquer thinner, since the paint from that era was all lacquer. What worked best was denatured alcohol, which led me to believe the coating was shellac-based. It took an absolute ton of effort, but eventually I got it all clean.

Bill
 
MattPersmon- Yes indeed, it *does* protect/look awful! Cleaning it up, but not *off*, undercarriages is one huge challenge.

Billy Jack- Huh, that`s a new one for me! The domestic undercoating/rustproofing I`m familiar with from back then was always some variation on Ziebart, easy-peasy with most any solvent.
 
Accumulator said:
Billy Jack- Huh, that`s a new one for me! The domestic undercoating/rustproofing I`m familiar with from back then was always some variation on Ziebart, easy-peasy with most any solvent.
Click to expand...

I had both to deal with on my Camino. Originally, it was Ziebarted, then at some point after, coated with some type of clear dressing. Once I used the alcohol to get the yellowed clear stuff off, I then had to deal with the 20 year old rustproof on the inner structure of the fenders. Unlike fresh rustproofing, which easily dissolves with a mineral spirits-based solvent, this stuff was almost crystallized. Don`t even want to think about the effort put into that project, all in the quest to avoid points deduction in judged shows.

Bill
 
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