CAR Is it wise to pressure wash the undercarriage of an old car?

8 Ball

I'm taking my ball and I'm going home
Jan 30, 2001
4,172
right side corner pocket
It’s filthy under there and I’m going to scrub it down with a wire brush. But I want it CLEAN, so I can spray it down with rust inhibitor. My plan was to pressure wash it then blow dry it with my leaf blower. How do professionals/intelligent people do it?


iballrealanswers
 

JohnnyBeagle

Calcutta Viper
OT Supporter
Oct 18, 2004
107,418
Digital Nomad
I have a related question... I got a bit wreckless with my pressure washer and knocked a little chunk of the factory undercoating off the wheel well of my S2000 so there's some exposed metal in there now. Can you buy that stuff in a can or something? I wouldn't mind covering it back up
find this product near you

 

Shep762

Well-Known Member
Sep 2, 2003
10,925
Just 909 things
Doubt the ecm/tcm are exposed so you should be gtg. Take it easy around the electrical connectors, ign coils, etc anything electrical

I do this all the time, don't like working on dirty engines :o
 

WhiteLightning

Be Excellent to each other.
Sep 12, 2001
29,635
Northeast
I have a related question... I got a bit wreckless with my pressure washer and knocked a little chunk of the factory undercoating off the wheel well of my S2000 so there's some exposed metal in there now. Can you buy that stuff in a can or something? I wouldn't mind covering it back up

I use POR-15, they typically come in big expensive jugs but they also sell 4-oz containers for tiny jobs. The first time I did it, I went half assed by wire brushing then applying. About a decade later I did it again, this time with the suggested degreaser and metal prep chemicals. Should last decades. There’s a spot on my glasses that I assure you is never ever coming off. My trucks frame should be in one piece until the sun becomes a red giant.
 

Deleted member 9731

I just want to touch up the spots I blasted off. It's hardly a big deal but I'm super anal taking care of the car lol

View attachment 100725
I used por 15 undercoating spray to touch up a few areas. And to coat over some dirty ass areas that just wouldn't return to a nice black in my wheel wells. It takes forever to dry and is messy but it worked.
 
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DizzyEdge

Vax me Trudaddy
OT Supporter
Dec 16, 2007
20,777
Calgary, AB
77 Datsun They are notorious for rust; mines in good shape thou. I can’t drive it cause I removed the gas tank for cleaning.
How are the front strut towers doing? I recall the "Car Wizard" on YouTube remarking that a friend of his had an old Z car and the strut tower had rusted out and crumpled leading him to drive into the side of a moving train and die.
 

jelloslug

OT Supporter
Jul 1, 2003
60,243
Greenville, SC
I use POR-15, they typically come in big expensive jugs but they also sell 4-oz containers for tiny jobs. The first time I did it, I went half assed by wire brushing then applying. About a decade later I did it again, this time with the suggested degreaser and metal prep chemicals. Should last decades. There’s a spot on my glasses that I assure you is never ever coming off. My trucks frame should be in one piece until the sun becomes a red giant.
I have POR-15ed lots and lots of my old Eldorado. For the trunk, I decided that buying a quart was a good idea after my last 4 OZ can only did a tiny spot.
 

jelloslug

OT Supporter
Jul 1, 2003
60,243
Greenville, SC
I'm super careful with it and never get close to the paint but had an idiot moment where I was like 'I'm in the wheel well, I can go closer' and then the little bit of undercoating flew off ...oops
If a pressure washer with a normal tip took it off, it was going to come off at some point anyway. Even worse is if had a void in it that trapped crud back behind it.
 
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8 Ball

8 Ball

I'm taking my ball and I'm going home
Jan 30, 2001
4,172
right side corner pocket
How are the front strut towers doing? I recall the "Car Wizard" on YouTube remarking that a friend of his had an old Z car and the strut tower had rusted out and crumpled leading him to drive into the side of a moving train and die.
Thanks for that. They’re fine; I just had all four shocks replaced a month ago actually. The cars in really good shape for its age. I’m the 3rd owner, I bought it from the original owner son and the original owner baby’d it and documented everything, including the gas fill ups :rolleyes:

but I want to re-undercoat it before Florida humidity sets back in
 
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DizzyEdge

Vax me Trudaddy
OT Supporter
Dec 16, 2007
20,777
Calgary, AB
Thanks for that. They’re fine; I just had all four shocks replaced a month ago actually. The cars in really good shape for its age. I’m the 3rd owner, I bought it from the original owner son and the original owner baby’d it and documented everything, including the gas fill ups :rolleyes:

but I want to re-undercoat it before Florida humidity sets back in
Lol at recording fill ups. But also a good sign of great care.
 

popey

OT Supporter
Dec 25, 2003
7,048
don't places do like a steam cleaning or dry ice thing? or you trying to DIY it?
 

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