307 Engine Coolant Passages--Cleaning

[Dave K.]

Is there a drain for the coolant passages in the block? I noticed a plug on the driver's side by the pan but am assuming this is for the perhaps an oil galley--dunno. I want to flush out the passages really good as I found some slimey crud on the newly installed t-stat I pulled while diagnosing some cooling problems.

Thanks, Dave.

[turp mcspray]

There is a pipe plug on both sides of the block. They can be a pain to remove. Especially in the vehicle. I always like to replace them with petcocks.

[Dave K.]

Thanks, I'll give it a shot but understand what you're saying about pulling them--I'm sure it will be a joy given the restricted access in the area. Wish I had one of those pipe plug sockets....

[Dave K.]

Off to Sears to buy some--long overdue anyway.....

[Boog]

You could use a cooling system cleaner. Dupont used to sell a two part cooling system cleaner. I'm sure there are other brands. I used it in an old truck many years ago. It left shiny metal inside the rad and block. Be forewarned though if there are any weak components like freeze plugs and water pump this cleaner can spring leaks. Replacing freeze plugs with the engine in the vehicle ain't fun either.
I've heard some guys put Calgon diswasher soap in their cooling systems and run it for a while then dump it and flush. It's said to be good at disolving oily substances.

[Dave K.]

Thanks guys. I was able to get the plugs out with just a bit of oomph. The coolant in there came out pretty clean but I'm going to pull the water pump and flush out that way and see what comes out and plug it back up and run'er for a while and see how she goes.

[Dave K.]

Thanks everyone, got it sorted. Likely some trapped air which gave me the initial issues with temp. Cleaned everything out and ran 'er and went up to 190 and then temp dropped as it should when the tstat opened. Runs great.