3.0L engine swap

[Farrar]

Just got back from a test drive. Mostly stop-and-go traffic. Engine stayed 205°F or below. A/C blew nice and cold.

Got home and saw my horns sitting on the workbench. Oops. LOL

Anyway, it was a nice drive.

[Lwanmtr]

Shame on you going out without your horns...what will all the other vikings say?

[Farrar]

Wait for it...

(Bloopers included.)

[Drive Stainless]

Wait for it...

(Bloopers included.)

I don’t think it’s rust. I think it’s solidified Dexcool you’re flushing out. Search “dexcool sludge” and see if it matches what you’re seeing.

It will all flush out, eventually. 2oz of Cascade helps.


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[Farrar]

Search “dexcool sludge” and see if it matches what you’re seeing.

I'd never heard of that ... but it certainly fits the symptoms. I wonder if the previous ooperator of the 3.0L used Dex-Cool...

I used an entire bottle of liquid Cascade detergent before the radiator swap, and it got rid of quite a lot of sludge. But obviously there is more entering in the system. Perhaps someone ran Dexcool in the 3.0L engine before I got it, and it is all breaking slowly free.

If I'm not using my drain valve, it's very difficult to catch what comes out of the system, so backflushing (garden hose connected to the lower radiator hose) generally just involves me removing the thermostat and the block drains, then turning on my garden hose and flushing from the bottom of the radiator and all of the brown gunk just runs down the driveway. I'd like some better way of backflushing. Maybe I will re-route the rear auto-bleeder to a 5-gallon bucket and plug off the return barb on the expansion temporarily.

Someone on another forum suggested running the engine while flushing with a constant supply of fresh water. That may have something to do with the fact that the sludge seems to break away when the engine is hot. I wonder if I could manage to somehow flush the engine while running it. I'm going to have to get inventive...

Thanks for the tip, Matt!

[Farrar]

Of course the question has been asked, "If your coolant is working, why worry about the brown stuff?"

The answer is that the brown stuff will eventually form clogs. I have a nice new radiator and I don't want to kill it.

[Farrar]

And sure enough, after a longer drive today, the coolant I drained was even more brown than yesterday.

Side note: My daily driver also has orange coolant, but it's not Dex-Cool. I bought the car used. At one point the thermostat failed closed. Most thermostats are designed so that they fail open. Turns out the cooling system was clogged with brown gunk. When the engine got too hot I took the car to a shop and they told me about the gunk. They flushed the system, replaced the thermostat, and I have not had a problem since. Now I am wondering if the previous owner used the wrong coolant...

[dn010]

When I first did my engine swap and was trying to get it running on EDIS, I filled the system with straight water and left it that way for months. I ended up with rust particles. So I pulled the upper radiator hose connection and ran a garden hose into the expansion tank. I let the engine idle with the garden hose on and it flushed a good amount of crap out. I suppose if you wanted to flush the radiator as well you could pull the lower hose but you'll have some of the expansion tank water running out. I had a new radiator and did not want all that crap to go in it. I did run Dex Cool for years in the PRV but went to Zerex green. Thankfully I never had sludge issues.

[Farrar]

According to a few articles and videos I've found on the subject of Dex-Cool sludge, the problem is that the sludge forms when air is introduced to the coolant. So if there was a coolant leak that allowed air to enter the system, it was possible for the sludge to form.

The last time I drove the car the coolant temperature held steady at about 200. It looks like the more gunk I get rid of, the cooler the system runs. I will just try to keep it as clean as possible -- keep the drives under an hour and flush after every drive.

[Farrar]

I started to drain some coolant after today's short drive, and it looked perfectly fine ... so I stopped draining and left it alone.

Two possibilities:

(1) I got what was left of the brown powdery stuff
(2) The engine needs to get hot to dislodge the brown powdery stuff

I have an appointment in Miami tomorrow. It's 60 miles round trip, mostly highway driving. I think I may be bold enough to take this car to that appointment... But I may bring some supplies with me.