What is the best way to remove stubborn gasket material and sealant from the mating surfaces. Specifically the oil pan mating surfaces and the front timing cover/water pump surfaces. I always have used either a razor or a paint scrapper on cast iron, but being that everything is aluminum I'm afraid the surfaces will get scratched to an unsealable condition. I tried some permatex gasket removing compound that I had laying around, but it didnt really do much. Also a little brake cleaner on a rag.

 

I just went through this a few months ago on my water pump. The gasket was so firm and stuck that it took me 3 days after work of soak 5 minutes, scrape 5 minutes, repeat. I started very conservatively with a plastic scraper and WD-40, and slowly started going bigger and bigger with stronger solvents and metal scrapers. I ended up getting a gasket scraper from a mechanic friend, but that is a steel tool so you must be very very careful not to score the aluminum gasket surface. For the waterpump, I think I would have saved time in the long run by pulling the alternator to make access to the top part of the gasket easier.

In the long run, it's down to patience. Make sure to keep all scraping tools at a 90 degree angle to the scraping surface. Scaping at an acute angle (as seems intuitive) significantly increases the chance you'll gouge the aluminum block.

 

I use a razor blade and then final cleanup with a scotch brite pad and rubbing alcohol.

 

Yep... Razor blade scraper then scotch brite pad. There is a technique to using razor blades on aluminum though. You need to start at a shallow approach angle and keep the blade extremely flat to the surface using light pressure. The razor will gouge the aluminum if you're not careful. Start slow till you get the hang of it.

 

spray carb cleaner on to the gasket material.
Carb cleaner is so nasty, it usually gets the gasket off.
Then gentle with a gasket scraping tool which you get from the auto parts store.

 

I've just been through a similar nightmare a couple of weeks ago with my Pajero but it was the rocker gasket groove on the rocker cover and the mating land on the alu head. The gasket wasn't a problem removing from the rocker cover but getting all the RTV sh!te off of the rocker cover and cylinder head took half a day as it took a lot of time and patience and also required stuffing wiping paper into every oriface in the head so the RTV didn't drop down into the head/block. This time I didn't use any sealant at all just the rubber/plastic rocker gasket and so far no leaks.

PS I used a craft knife initially with a normal blade and later a square headed scraper blade a bit like a narrow 3/8" razor blade. http://xacto.com/products/cutting-so...-Blades-2.aspx like the top blade in the picture.

 

they make plastic razor blade

 

I initially was trying some plastic paint scrappers that I found at Home Depot, but they weren't "sharp" enough. I've been trying a set of non-marring scrapers from Harbor Freight that I saw on sale (4 Piece Nonmarring Scraper Set) with limited success. The RTV is the tough stuff. They are working on the water pump OK, but on the oil pan with the baked on residue they didn't do anything at all. I ended up using a razor blade.

It looks like my water pump (that was replaced by a previous owner at a Land Rover Dealer) has RTV on both sides of the gasket. Is that normal?
The timing cover mating surface is flat, but I'm noticing that the mating surface of the water pump isn't very flat at all.

I don't see any RTV between the timing cover and the block. I've been going back and forth on whether I should put any on there when I seal it back up.

I've been using brake cleaner, but I'll try some carb cleaner. I'll look into the plastic razor blades too.

 

auto body shop supply house

 

It looks like Autozone has them. I'll pick one up today over lunch and give it a shot. Thanks for the ideas.