Mx5 with surface rust

redchicken · Postby **redchicken** » Fri Oct 13, 2017 10:03 pm

Hi Guys great forum
My recently purchased mx5 has a fait bit of surface rust including the engine. Should I be worried? Should I be doing some rust prevention? I have also noticed a bit that has comes threw the paint above windscreen? Thoughts?

cookie · Postby **cookie** » Sat Oct 14, 2017 7:27 am

redchicken wrote:Hi Guys great forum
My recently purchased mx5 has a fait bit of surface rust including the engine. Should I be worried? Should I be doing some rust prevention? I have also noticed a bit that has comes threw the paint above windscreen? Thoughts?

Mx5s are far more immune to rust than 80's jap cars. Some of this is due to much better treatment of the steel, but also because they're 10+ years newer. Now they're close to 30 years old however and rust will be an ongoing maintenence from this point on. Windscreen rust is fixable but is a windscreen out job. I'd be contemplating pulling the interior out and doing a check under the carpets etc. If it's covered in surface rust then reevaluate whether a full strip down and respeay is in the budget, if not, fix the unseen areas with converter/primer then just enjoy the car. Rust on the engine block is common, no big deal until you try to work on it. My 91 example has spent 90% of its life garaged and has virtually zero surface rust, I imagine yours lived my the sea for many years!

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project.r.racing · Postby **project.r.racing** » Sat Oct 14, 2017 9:16 am

Depending on the year model you have. Mazda begun to nickel plate their chassis and panels from the mid 90s. You shouldn't have any rust issues unless there are scratches deeper than the paint and undercoat go.

Some where in the mid 90s started doing the process. A know for the new 94 323s the begun this process. The older 90-94 323 did not. So unsure when they started with MX5s.

So if it is just surface rust, it shouldn't be a problem if nickel plated.

Rust on an engine is pretty common. Iron block. Especially if the car had infrequent runs. I wouldn't worry about it on the engine.

93_Clubman · Postby **93_Clubman** » Sat Oct 14, 2017 9:47 am

redchicken wrote:Should I be doing some rust prevention?

Yes, clean out all the drains regularly: viewtopic.php?f=28&t=35601

Lokiel · Postby **Lokiel** » Sat Oct 14, 2017 10:16 am

project.r.racing wrote::
A know for the new 94 323s the begun this process.
:

Were you drunk when you typed this or are you learning "Chinglish" as a 2nd language?

- it's right up there with some of the best incomprehensible Chinglish instructions I've ever seen

project.r.racing · Postby **project.r.racing** » Sat Oct 14, 2017 11:15 am

Lokiel wrote:
project.r.racing wrote::
A know for the new 94 323s the begun this process.
:

Were you drunk when you typed this or are you learning "Chinglish" as a 2nd language?

- it's right up there with some of the best incomprehensible Chinglish instructions I've ever seen

I got back from Japan a week ago. I'm still in Japlish mode.

"I know for the new 94 323, they begun this process" was what I should have typed.

Mr Morlock · Postby **Mr Morlock** » Sat Oct 14, 2017 8:49 pm

chassis' and panels are not nickel plated in modern cars to my knowledge. Certain compositions of materials resist rust.

Sheetmetal will rust almost before your eyes if its not treated properly. Thats why we have zinc or galvanising etc that was employed on roofing. Fasteners on cars and other building external items are generally zinc plated or sometimes stainless steel. There are other finishes but ZP and passivate is the usual - yellow/ gold on fasteners has a better salt pray resistance than clear- take a look under the bonnet.Fasteners are plated in bulk e.g. in a barrel. A bit of rust on blocks and engine parts are not likely to be a problem. Rust in sheetmetal is a different ball game if it gets into panels it can kill any car. Holdens in the 60's and 70's would rust in 12 mths.

One of the first big problems encountered by Toyota shipping cars to USA - 60's or thereabouts was rust which appeared on the voyage - i.e. salt and salt spray resistance is still a measure of performance in labs- e.g. spec calls for 96 hours or 144 etc.Toyota had to fix it or they would have lost their business- they did fix it.They were smart long before Ford and Holden got their act together in AU. Pre treatment and good design is essential.

If there is rust around the pillars its worth checking it out.

JBT · Postby **JBT** » Sat Oct 14, 2017 10:44 pm

Did this car sit in flood water or something?

project.r.racing · Postby **project.r.racing** » Sun Oct 15, 2017 7:16 am

Mr Morlock wrote:chassis' and panels are not nickel plated in modern cars to my knowledge.

You are correct. Dunno why I said nickel. I should have said zinc.

hks_kansei · Postby **hks_kansei** » Sun Oct 15, 2017 7:24 am

As far as rust goes, if its only on the surface, ie it scrubs off easily enough, and you can stab at it with a screwdriver without punching through, you should be able to just treat it with rust neutraliser.

Just follow the instructions on the bottle of whatever one you use.

If the rust is heavier, or has thinned the metals enough that you can poke through it, it needs to be cut out and have replacement metal welded in.

Either kind you'll still need to paint over the repairs afterwards, to seal it and stop it just coming back.