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General Discussions about the 300M and other LHs

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 #392282  by tkr87
Hi Guys,

I'm wanting to get me another Special and I found one, it drives nice, no problems other than needing brakes, but it is a rustbelt car. Here are some pics from underneath I was able to get. Is this terminal or does it look like just surface rust I can sand down, POR-15 and keep it on the road?
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 #392283  by FIREM
Very hard to determine when and where rust will go once it takes hold. Kind of like termites, can kill them but the internal damage is done. One tell tale sign is at pinch welds and where "frame" gussets meat the floor pan. If budging or distorted rather than surface rust is present, its deep seated and will continue.
I am not a believer in POR 15 (or other 'Rust Encapsulates" at the stages of rust in your pictures. POR 15 is $$$$ and results directly related to the detailed prep needed.
A shot of 'Rust Reformer" products followed by "Fluid Film" or similar product to slow the process and get a few more years out of it is more practical and cost effective. Those products seep in and slow things down. Encapsulating products would lock in 20+ years of decay and will rot form the inside out.

Al brake lines, strut spring seats, fuel tank straps, hood, trunk, door panel pinch points, windshield channel all high on the rust inspection list.
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 #392284  by cin993
I've used POR15 a few times, first time maybe 3-4 years ago.

Industry pro's will tell you the silver color is best for adhesion to metal and longevity; even the label mentions it.

I used a strong wire wheel on a makita angle grinder, heavy grit sandpaper to remove as much surface rust as I can. Follow the por15 directions-- cleaned surface well, used the acid etching primer (metal prep) converts rust and it works, rinse and dry everything 100% dry no moisture at all, i used a heat gun to be sure, paint 2-3-4 coats within about 30minutes or finger drag dry. use cheap disposable brush bc the paint will not clean off with anything..maybe porstrip, never tried

top coat the por15 if the area see's sunlight. POR15 worked very well for me. $60 quart was worth it. I use Fluid film also... good to coat the underbody etc but it's not cheap either
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 #392286  by piperdog
I haven't used POR15 so I can't comment on it. I do, however, agree with FIREM that light oils (e.g., Fluid Film, Rust Check, Krown Oil) have an advantage that they creep considerably and soak into crevices that otherwise may not be reached by other products. I've often had my 300M professionally sprayed with Krown Oil and I have also used it for spot applications. It is very effective at stopping rust. It is easy to apply. On the downside, it has to be applied periodically because the light oil evaporates and may also be washed off gradually. I think it also swelled some of my rubber door stripping but not enough to bother me vs keeping the rust at bay.
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 #392287  by tkr87
Good responses here as usual! I appreciate it! So, to get to the pressing issue, is there a consensus on whether these pics look like a lost cause? The rest under there was clean.
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 #392289  by M-Pressive
That third picture would have me looking elsewhere.

What is your goal with the car? Drive it a couple years or longer?
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 #392290  by monte4
I'd also look elsewhere. I'm from the rust belt and from your pictures that car is well on it's way to rust out. If you start grinding or sanding that, you'll have holes or the remaining metal will be so weak that it will have holes shortly. The only thing you can do at the present stage is to get it Krown or equivalent sprayed or go through a half dozen cans of Fluid film. Sorry for the bad news but that car is not a long term keeper. If you want the car for short term then get it sprayed a couple times a year. I get my 4x4 sprayed in the spring and again in the fall being as it's my winter vehicle.
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 #392291  by tkr87
Roger that guys! I live just outside of the heavy salt belt here in Virginia, so I usually balk at rust. The closest Krown applicator is a couple of hours north of me in Pennsylvania and like you guys aid, that is just a band aid at this point. I appreciate the feedback and expertise. I'll be patient and wait for a better Special!
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 #392292  by LUNAT1C
Definitely looks to be well on its way. One way to check is to press a screwdriver into it. If the metal flakes or easily deforms... it's too far gone. Might be good for a few more years if you string it along with rust reformer and fluid film... but its days are numbered.
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 #392293  by tkr87
I'll watch the buy/sell here for a clean one near me, as well as FB Marketplace. Slim pickings these days for sure though! One will pop up though, I'll just have to be patient! I'll rejoin the club once I find another one :D
 #392326  by rustybronco
To put it plainly rust sucks. Living in the rust belt means you can't own nice things.

My '02 M is showing big time rusting in the front sub frame area. It will still be good as a daily driver for a few more years but not as mine. I am buying a 2003 300M special to replace it with. I'm tired of dealing with rust. Now to find a motor for the replacement.
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 #392334  by FIREM
Welcome Dale.
Looking for an Engine??
 #392402  by rustybronco
In a round about way yes. I have the engine that is in my '02. The gent I bought the special from still has the original engine that includes reworked heads, crank kit, new pistons and rings. I dont know yet what Avenue I will take as of yet but always open.