How to clean the underside of your car; The Easy Off Challenge

How to clean the underside of your car.

1969 AMC AMX engine bay restoration

The traditional cleaning method for your greasy underside has been steam cleaning, media blasting, or for the really messy spaying on Gunk or some similar product. Our Project Barn Find AMX had 12 years of grime on it but had a very sound and relative clean underside. We had always heard that Easy Off Oven Cleaner was a better grease cleaner than Gunk and similar automotive products. Personally, I have found Gunk and similar products nearly worthless.

I went to the local grocery store and picked up two cans of Easy Off at $6 per can and two cans of generic oven cleaner at $2 per can. How will they do? How do they compare? Should they go in the “do not buy trash can”?

Phase 1 was the initial power wash.

Our approach was to knock off the worst of the dirt and grime with an initial power wash. No need to waste the products on dust! We went over the entire car with a power washer only, no soap or any degreaser; just good old water. The results were remarkable, but remember this car had not been on the road since 1981. However, it was driven from 1969 until parked in 1981. That is still 12 years of regular everyday usage.

Phase 2 was all about the “Oven Cleaner” Challenge.

The second power wash of the engine bay and underside was preceded by a liberal application of oven cleaner. We purchased 4 cans for the cleanup on our AMX. We used two cans of the expensive Easy Off and two cans of some generic oven cleaner that costs one third the price of Easy Off. We sprayed one half the underside with one and one half with the other using the drive shaft tunnel as the dividing line.  We used one and one-half cans of the respective product on each area of the car. Before I give the results away check out the photos below.

Easy On…

1969 AMC AMX engine bay restoration

We spayed anything that hinted of grease or oil.

1969 AMC AMX engine bay restoration

Since the engine bay is also going to be completely repainted we were not worried about the oven cleaner damaging the paint. However, you should use caution. We let ours sit overnight and it did remove paint better than some paint removers we have tried!

1969 AMC AMX engine bay restoration

We really laid it on under the car. Surprisingly, there was not a large amount of oil and grease under the car but we are going to get rid of all of it.

1969 AMC AMX engine bay restoration

1969 AMC AMX engine bay restoration

The differential was probably the dirtiest part of the entire car so we really soaked it down.

1969 AMC AMX engine bay restoration

Some of what you see under the car is not grease and dirt but factory applied undercoating. You can tell the difference because the undercoating is rock hard, we have no intention of removing it.

Easy Off!

1969 AMC AMX undercarriage restoration

This is the underside of the front suspension. It cleaned up great.

1969 AMC AMX undercarriage restoration

Little more than a scuffing should be necessary to paint these items.

1969 AMC AMX undercarriage restoration

1969 AMC AMX undercarriage restoration

The original color of the car was white and we even got down to the original paint on the uni-body frame. They must have painted this area black when the car was repainted red.

1969 AMC AMX undercarriage restoration

The differential cleaned up real well but we will go back over it with a second coat of oven cleaner.

1969 AMC AMX undercarriage restoration

Can you believe how well this cleaned up?

1969 AMC AMX undercarriage restoration

Remember, this is pressure wash, oven cleaner and NO steam or degreaser.

1969 AMC AMX undercarriage restoration

Ok, we are going back with the remaining one half can of cleaner on each side for one more application to hit a couple of heavy grease spots that didn’t come completely clean in one application. We used a total of 3 cans of oven cleaner up to this point. Although this was not a scientific test we could not notice any difference between the two products. My recommendation; skip the automotive store products; go to the grocery store and buy the cheapest heavy duty oven and leave the Easy Off on the shelf. There is no guarantee you will have the same results but we are going to try this on some more cars real soon!

Comments (7)

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  1. Anthony Miller says:


    I own a 1967 barracuda fastback and would appreciate your input on how to completely clean the car regardless of repainting it.



  2. Richard says:

    You have a very open ended question. It is difficult to answer. I am assuming it has some unusal issues beyond the typical. There are many good products at you local auto parts store for cleaning, carpet, windows, seats etc. I suggest you stay with the name brands. If you are talking the exterior then it really gets difficult. Check out Meguiars videos on line at their web site and also on YouTube for more details.

  3. Vlad says:

    Well done!

    To finalize the procedure as far as I understand:

    1. Wash under the car with high pressure hot water.
    2. Let it dries
    3. Apply Easy Off toughly on the wet bottom and chassis of the vehicle not to allow it to come on the painted panels (doors, trunk, hood etc)
    4. Wait overnight
    5 Repeat step 1 and 2
    5. Repeat step 3
    6. Using some tools clean the rust where possible
    7. Repeat step 1 and 2
    8. Apply Por-15 rust converter or KBS rust-Blast following its manual
    9. Paint the bottom using Por-15 or KBS Seal or whatever is suitable (epoxy primer + some paint etc) , Rust Oleum primer + paint etc)

    Is it correct what I wrote above?

  4. Richard says:

    You have it mostly right. I did not use hot water in any of the steps although if you have it available it would help, just don’t burn yourself with water that is too hot because you will get wet. I also let the car dry before application of the Easy Off.

  5. Vlad says:

    Thx Richard.

  6. Daniel Baumann says:

    Not sure if you’ll reply anymore..late question, but was wondering if the oven cleaner would or did have any adverse affect the wires, rubber, boots,etc etc, under the car. Will be doing this to both my Subaru and a 442 that I will be getting this spring.

    Cool site.

  7. Richard says:

    I did not experience any that I could see.

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