Author Topic: Undercoat ?? vs. Rustproof ?? (Read 17201 times)

95off_road · « **on:** April 28, 2005, 04:53:19 pm »

So I had my 95 Pathfinder in for some work at my local mechanics shop last week and while up on the lift, I noticed very bad rusting on the rear frame rails. Evidently, a known problem with 93-95 Pathys.

Now I'm getting advice from everybody I talk to and some are telling me to get it undercoated and some are just saying use Krown or RustCheck etc... What exactly is undercoating?? I thought that was part of the factory process during manufacturing? Are they talking about the crap the dealer tries to sell you? I've had it rustproofed in the past and the body is in excellent condition. The frame rails are boxed in and from the looks of the design, it's just made to trap salty water... Ideally, I'd get someone to lift the frame off and sandblast and POR-15 the frame,..but I'm not sure I'm up for that type of cash. What other options do I have? I'd like to save the frame from further deterioration for at least a couple more years.

articsteve · « **Reply #1 on:** April 28, 2005, 05:32:28 pm »

I've had it rustproofed in the past

With what product?

slybry · « **Reply #2 on:** April 28, 2005, 07:43:36 pm »

It is too bad you waited 10 years to ask this question. Its best to make sure rust never starts rather than trying to fix the damage it has done. I highly recommend Krown, RustCheck or Dura Check. They all have a chemical spray that is sprayed on the underbody and inside panels through holes they drill. The chemical runs into crevices and then turns into a gummy substance. It cost about $100.

If you hold onto cars for a long time it is a great idea. Your car will look better longer, not cost you for repairs due to rusting componants and have higher re-sale

If you get it done every year they will guarantee the car forever. I do not trust garanties too much and also find it expensive to do as I have 2 cars. I have decided just to get each one done every second year and it is working out great.

We live in Montreal which is the rust capital of Canada. My mom has a 1994 Sentra we have had sprayed about 6 times and there is no rust at all. I sold a 12 year old Madza 323 and a 10 year old Stanza both with no rust anywhere. I presently have a 97 Acura that is in showroom condition. The underbody is perfect.

The application does not just help the body and frame but also things like the brakes lines, gas lines and Gas tank.

Get it done and do not buy applications from dealers. The dealers will hide behind loop holes in contract when rust appears.

I just brought a friend to a body shop and he is going to drop about $700 bucks getting the rust on his 1993 Civic fixed. All I could think of is if he spent the money before on preventing the rust he would not be at the shop. Fixing a rusty car is never as good as a car that never rusted.

Don't listen to those who say the holes they drill will rust. That is BS. Have had no problems with that.

Stick to a garage that specializes in rustproofing. Not a garage that does mechanics and does rustproofing on the side. They will most likely do a better job applying the spray. The effectiveness is only as good as the application.

If you happen to live in Montreal go to DuraCheck on Pierrefonds Blvd. A great place that know their stuff.

Stay away from Metropolitan Rustproofing. They are the McDonalds of the business and do not do as good an application.

95off_road · « **Reply #3 on:** April 28, 2005, 08:28:47 pm »

Thanks for the info. I'll go see the guys at my local Krown shop and see if they can delay the inevitable - death by rust. One guy I talked to just laughed and said that even if I had done the rustproofing every year, it wouldn't have helped much since the rust I have is more due to poor design and bad steel. He claims that Nissan changed the frame from 92 to 93 model year, and from 93-95 they all rusted badly on the frame rails from behind the rear doors to the back bumper.

It's really obvious that it is just the frame since the other underbody components (i.e. suspension, brake lines) are in very good shape for a 10 year old truck driven in SALTY Ottawa.

barrie1 · « **Reply #4 on:** April 28, 2005, 08:42:50 pm »

You can have it Rust proofed but I would recomend the the Por-15 Route 1st. I have used this product and it is easier then you think. Just wire brush the rust off and then use a brush and paint the whole bottom end of your vehicle. The por-15 will do the rest. It eats the rust and also seals the metal in a plastic like coating. As you already have rust damage this will stop any further damage and make the bottom of the vehicle look like new again as well. I am a firm beleiver in this product as I did the entire frame off restoration under my truck with it. This product really works extremely well. You can undercoat after if you feel it is necessary. This can be brushed or sprayed onto the metal. Your choice.

ericthejet · « **Reply #5 on:** April 29, 2005, 11:22:45 am »

Go to C Tire and get a wire brush and a can of undercoat. Do it yourself as the rust that has already started will not stop. The best you can do yourself is just help prevent futher rusting. I think spending cash at Krown etc. although not a bad idea is a bit beyond the point now. Coat all seams, etc just make sure you get rid of the grit first. I have done this to all my cars in the past and it works well. MOP.

bmw · « **Reply #6 on:** April 29, 2005, 03:42:39 pm »

See this thread...
http://www.canadiandriver.com/discus/messages/1496/27023.html?1111616345

Get the Krown...much better than Rust Check. Not an opinion...we did some thorough testing.

bmw · « **Reply #7 on:** April 29, 2005, 03:45:37 pm »

Don't listen to those who say the holes they drill will rust. That is BS. Have had no problems with that.
-------------------------------------------------
The point is, why drill a hole if you don't have to.

There are sooooo many access holes in a car covered by rubber grommets, that can be removed and then replaced.

mrthompson · « **Reply #8 on:** April 29, 2005, 03:52:16 pm »

Keep an eye out for any cracks that may be forming in the rear frame rails. My buddy's sister had (until recently) a 92 Pathy. There was a long crack by the rear tire on each side; one side was worse than the other. If you were to push on the body, you could see the crack open and close. Nice.

blue_oval_fan · « **Reply #9 on:** May 01, 2005, 05:16:56 pm »

Since 1992,I've been taking my cars to Krown for the annual spray. My '92 Taurus had absolutely no rust when I traded it in '99 for the '97 T-Bird.The 'Bird has been treated since '99 and still looks like new underneath.
Okay, I admit that I don't drive it in the winter when there's slush and salt on the road,but the wife's 2000 Taurus hasn't shown any rust,either.
As far as I'm concerned,the $ 100 plus tax per car is money well spend every year.

barrie1 · « **Reply #10 on:** May 01, 2005, 07:19:35 pm »

The Por-15 will make the vehicle look like New again where ever it is applied. I do recommend undercoating after as it certainly will help with any vehicle. The Por-15 is around $52.00 a Qt and worth every cent as its quality is 2nd to none. This is probably the best restoration paint in the world.