Rust Proofing a Saab 9-5

Tuff-Kote DinolMany of us wonder what to do when there are no new Saabs to buy for the moment. A lot of the comments on SU concern replacement options.  I did my homework and came up with the conclusion – I don’t want to replace my car, I love it!

I bought my car 2010, just after the new year. Saab was already in a shaky situation and I wanted to buy a car which would last a long time even if Saab would not make it as a company. I got hold of a 9-5 Griffin Vector Sport. It is basically an Aero, but with the 210hp 2.3l Bio Ethanol engine. It was less than one year old and was previously driven by a shop floor manager at Saab in Trollhättan.

I can’t really find any car with good value for money which is fun to drive, beautiful, eco friendly and can fit my entire family.

So how do you keep your darling in good shape? I decided to give it some TLC in form of some good old rust proofing. I have already applied paint protection and this was the natural next step.

I decided to go with Dintrol or Dinol as it is also called, after recommendations from a relative who has been in the business. Dinotrol is a rugged product with a deep penetration effect. The next step was to find a good workshop. There are several players in this field in the vicinity of Gothenburg where I live. I made my decision after talking to Ulf, a proper Saab nut like myself. Ulf has been a Saab mechanic since 1980 and has worked with Saab until he bought Protec. He has one 9-5 Aero and beautiful 9-3 convertible. This is a man who knows what he is talking about when it comes to Saab. Ulf promised that I could come by to document the different steps and that I could share the experience with the readers of SU.

The Tuff-Kote Dinol treatment is a thorough procedure which takes three days to complete.

Day one – Preparations:

  • The work is prepared using a unique treatment schedule for each car model with about 70 points.
  • The underbody plastics is removed and the car is thoroughly washed and left to dry over night.

Day 2 – Treatment

  • All of the vehicle cavities are injected. Sills, chassis, subframes, doors, hatch doors, pillars, boot and bonnet is treated with hot Dinitrol.
  • The final application is of Dinitrol underbody wax. All of the suspension and underbody is coated. The thicker wax will cope with mechanical wearing like stone chips.
  • The car is left to dry overnight.

Day 3

  • Verification of the work.
  • The car is washed to get rid of Dinitrol spots on the paint

Please refer to this page for a detailed description in Swedish. Below are some Pictures from the different steps of the treatment:

Under body plastics removed:

IMAG0880 (800x451)

A little rust in the rear wheel house. The coat is very thin behind the plastic cover. Newer cars tend to have ever thinner coats. I was prepared for the worst, but my car was actually in really good condition.

IMAG0878 (800x451)

Underbody protected with a golden brown layer of Dinitrol.

IMAG0886 (800x451)

Springs and arms protected.

IMAG0887_BURST001 (800x451)

Control-arm protected. Read more about control-arm issues in this previous SU post.

IMAG0892 (800x451)

Note that the brake tubing is totally covered. It is very common that brake tubes corrode in cold climate, especially when the roads are salted.

IMAG0893_BURST001 (800x451) edit

Two common weaknesses on a 9-5. 1: the gap above the sill. 2: A small hole in the wheel house plastic.

IMAG0895_BURST001 (800x451) Edit

Proof of the treatment:

IMAG0898_BURST002_COVER (800x451)

My Saab outside the old Saab office in Pixbo, where I live. Let´s hope the treatment keeps her in this condition!

My 9-5 in front of Saab in Pixbo 491 (800x533)

Any drawbacks? There is a distinct smell which I hope will go away over time. It is kind of pricy and I am not sure I will get the money back when I sell the car. But I hope that I will get less issues owning the car and that it will stay fresh. Time will tell.

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Ivar M

I have rust protected a 1987 SAAB 9000 T16 with the Tuff-Cote Dinol system once, and I recommend all to be careful of the choice of workshop. The workshop in Borlänge drilled new holes to inject the dinitrol in doors etc. The drilling machine had schrached of the paint around each hole with heavy corosion as a result. They also could not put back the removed parts properly. I got no refund or repair costs covered from them. I say no drilling of new holes.

Jan Ivarsson

I have been thinking about doing this when the car is new but does anyone have any experience in regards to what the mechanics think about this? I can imagine it’s not to much fun to do mechanical work if it’s needed when this covers nuts and bolts.

I just assume that the rust warrantys or what they are called would be forfeited and taken over by the company doing the coating but there still is a chance/risk of mechanical work being needed sometime.



Angelo V.

All good points raised—-cost/benefit, difficulty in removing screws,etc. if they are coated/sealed under coating and will this void manufacturers warranty? On cost/benefit, my thought is that if you are certain you will be driving in bad conditions—-salted roads (too often to do undercarriage wash each time you’re on those roads), or gravel/dirt roads that have stones flying up constantly—-if driving in that type of situation, the heavy undercoating seems like a good idea if you tend to keep your cars a long time. Otherwise, I think modern cars come from the factory with galvanized steel and rust inhibitors. For most… Read more »


What about the rust in the rear wheel house? Was it fixed or was it just covered up?


Well done JoPlSe. I have a Dinol chassis and cavity protection on one of my Saabs (1995 NG900), got it made in around 2004, since (and prior to) then there were no rust issues underneath, nor on the body, only a small pea was spotted recently on the lower corner of driver’s door, obviously for which cavity protection can’t be blamed. I think this is a must for any car. Don’t forget yearly re-checking is integral part of the protection system and another good point is the price here, in Hungary we can have it for around 140 EUR (… Read more »

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