Does the 98 come with a coolant drain plug on the side of the engine block? I was going through my Haynes Manual which noted it was on the side of the engine (driver), next to the coolant temp sender. Well my temp sender is on my t-stat housing. I tried peaking under the block to perhaps find one similar with no such luck. There does appear to be a counter-sunk allen head type bolt, which could be a drain plug, though it's hard to tell.

Reason being, I noticed some brown gunk in my rad tank. It has the same consistency of clay. I'm not worried about any major problems, because It's not really effecting performance. However I just did a coolant change 4 months ago. The coolant under the rad cap is still bright green. I did not pull the engine drain plug, and the flush itself was short due to a leaking exhuast, was annoying to listen to for 10mins. My guess is... Some gunk has been dislodged and found it's way into the rad tank. At which I need to do a really GOOD flush to get the rest out.

The PO was running the orange 50/50 which I've heard bad things about. Maybe this is what caused it. About the drain plug on the engine block... do people bother to open this? Or just run the flush with the radiator drain plug open, and hope everything finds it's way out?

 

Pull bottom hose and thermostat houseing stick thermostat housing back on with out thermostat in it wrap rag around garden hose so it fits tight in housing and flush away.

 

We double posted Freedgr! I meant no, not worth the hassle of pulling block plugs

No, not worth the hassle. Really pulling the lower radiator hose is the best bet to flush. if you search put "djb" in it! No, those block plugs are best left alone. (in my opinion)

Also, at least once on something when I tried the "silly drain", something jammed in it and it was a big pain. I guess with the new/improved plastic tanks that is even more fun.

On mine I pull the air-box and the lower hose to drain/flush it. No fun either!

 

Glad it's bright green and working fine. How thick IS this brown junk?

 

Like clay thick. You remember working with that brown clay in art class as a child... Like that.

The rad hose technique was one I used to do as a wee lad on my old Cutlass. Do I still want to let the engine run? Or pull the t-stat out and flush it cold? I used to let it run... trying to play by the books.

More importantly... Will Autozone take used antifreeze? I usually bring it to the dump, but it's a drive, and I always have to give up my buckets.

 

I'd flush it. Thoroughly this time. Yeah, I think you're right about gunk being dislodged.

I agree with taking off the lower rad hose, and not messing with the block drain.

Those drain valves on the radiator can be broken VERY easily, and then you can be looking at a new radiator. I had my Jeep on blocks for a few weeks last year because my son did that - opened the drain valve. Couldn't get it closed. I kept fiddling with it, and finally got it to close, but I was sweating it for a while there.

It's just best to leave those things alone!

 

Saw DJb "Peaking". I will guess he didn't chime because Freedgear nailed it. Pulling the t-stat housing with the lower hose off might be a good flush. Idk, just following these guys. Mine "auto flushes" right on the windshield when it needs it!

Ha! funny! No not just as a child...I did pottery demonstrations, got quite good on the wheel. 18 inch cylinder is "big league"

A warning here. Back around the back of #6 on an inline 6, if stuff settles there and gets too thick, the water jacket on #6 could be "compromised" . The cooling there on the cylinder wall can be inadequate and cause serous trouble. If you are sure you have a thick layer of sediment... Idk. Power wash with high pressure from the T-stat opening, maybe feed a hose in back there. (nose down). The flow behind #6 might be so low stuff will settle there. If you have a temp sender there you could blast in with a pressure washer through the hole. (pre94?).....Oops, 98, not 89...Some of our old things actually have a hole for the coolant sender there.

 

Should I be running the engine or no? Manual says to run it while flushing, which is what I've always done but if the t-stat is gone, I guess I don't need to wait for it to open. So flush with the engine off?

Also, I was going to use that radiator flush. Comes in a little yellow bottle.

 

Nailed it indeed......and don't forget critters like the stuff (and dogs rule).