Best way to clean surface of intake manifold

[Garth]

I’m working on a 2003 Dodge Caravan replacing the intake manifold and valve cover gasket. I’m in the process of cleaning the surfaces before installing the new gaskets. This is the second time I’ve dug down this deep into a vehicle. I haven’t had much experience and having no formal automotive training other than trial and error, books and now ETCG (Thank God for ETCG), I’m hoping I can get a critique of the work I’ve done from you more experienced car guys/gals. Any tips or suggestions would be appreciated as well.

So this is what I’ve done so far. I sprayed the surfaces with gasket remover, then used a razor blade type gasket scraper to remove as much of the crud. I was careful to keep the blade flat on the surface and work slowly, nevertheless, there were a few scratches made on the engine surface, so I’m a little worried about that. There were areas where the gasket remover couldn’t remove the varnished or discolorations, so I buffed the surfaces with an abrasive wheel on my die grinder. Now, I was aware of the hazard of getting dust from the abrasive wheel into the valve ports, so I did plug the openings to the valves to keep any debris out. I think I’ve got the surfaces clean enough and tomorrow, I plan to wipe everything down with some lacquer thinner to get any oil off.

I’m not sure just how shiny you need to get the surface clean to get good results. Is it important to remove the varnish spots or discolorations that the gasket remover or scraper can’t take off? Thanks in advance for any insight or suggestions.

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[Brian]

I wish you would have posted these questions before doing what you’ve done.
Never use a metal blade, they will easily gouge aluminum. NEVER ever use an abrasive wheel on any power tool, they remove material at an alarming rate. Do you have a very new metal ruler to act as a straight edge? Put the edge of it on the mating surfaces with a flashlight behind it. Are there now gaps that allow light through that should not? If so, go get a new manifold. Even a good used one. A machine shop may be able to resurface yours, just take it to them to inspect.
It can’t be the same for a diy as it is in a shop, and I understand the need to get it done and save money. Please don’t think I’m being a prick, I’m just cringing when I read what you wrote already.
My shop is closed, im retired. This is how I do mine at home.
If you don’t have access to a parts washer, then get a heavy leaf bag and some.paper towels. Roll the leaf bag down, lay the manifold bottoms up in it. Layer paper towels on the bottom of the manifold. Spray liberally with brake parts spray cleaner. Wrap up with the leaf bag carefully and quickly. Leave it a few hours. That spray cleaner evaporates rapidly. If you tied the bag off quickly enough, it should still be wet and have that awful stink to it when you open it again.
Eric has made videos on using a disc with plastic fingers on a drill to clean aluminum. That would be a fast way. A small plastic scraper, like the cheapest window ice scraper for $1 you can find is what you use to remove the majority of the old gasket. Green scotchbright pads are next. Use them with the understanding that it is not the pressure from your hand, but the time filled repetition that does the cleaning. If you press too hard, you can scrub off aluminum and make a very uneven surface area, that would be bad. Repetition is your friend here, not pressure.
That should remove the rest if your patient enough.
Again, if the mating surface is no longer flat with the straight edge, take it to a machine shop. They may be able to resurface it and maybe clean it more too. Keep in mind that typically charge by the hour, so do what you can first, then take it in.
Good luck sir.

[Garth]

Thanks for your advice, Peshewa. That’s a hard lesson to learn. Just when you think you know what your doing, eh? I wish I had thought of posting before getting to work on the cleaning. I’ll find a straight ruler today and assess the damage. The work I’ve done thus far was actually on the surface of the motor making things a little more painful. If I find the surface of the engine side isn’t completely flat, what am I looking at, a new block?? I’m guessing that would be a pretty penny to have resurfaced. Wondering if spraying the surface with a product like Hitek gasket sealant would fill in any discrepancies??

I’ll hunt down the ETCG video you referred to to learn a bit more about cleaning aluminum surfaces. I do have a small parts washer but I might try your idea of using a garbage bag to soak the intake manifold.

[Brian]

I think the block s iron. If a magnet sticks to it, it’s iron. Use more caution in the future obviously, but the block should be fine. Aluminum is much more delicate.

[James]

I have used a razor blade carefully many times with very light pressure and been fine. I do use brake parts cleaner land towels on surfaces and change oil following job. I have heard of gasket scrapers with graphite material that are supposed to be great but i have not used one myself. Hopefully all is well for you. I would stay away from the grinders. Best of luck.

[Garth]

I checked the block and it is aluminum. The good news is that when I checked it with a straight edge it came out flat except for one small area. I’m hoping it won’t cause a problem. As far as the intake manifold, I used a gasket removing spray and plastic scraper to get most of the debris off then soaked it in brake cleaner and then went over it with a green scotch-brite as per your suggestions. I’m quite happy with the results. Thanks again for your advice.
I’ve been hunting for the video you said Eric made demonstrating how to clean up aluminum with the disc with plastic fingers but haven’t come across it yet. Would you happen to know what the video might be called?

[Author]

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