Block plugs stuck, ideas for a good flush 450SL

[meltedpanda]

Block plugs won't budge on my 72 450, looking for working ideas to do a complete flush without thier removal, is it possible? I have searched and have seen suggestions but no tried and true methods, perhaps they don't exist
I am going to remove and replace hoses, themostat, as well as radiator, just wanna do it right since everthing will be off.

Do I have to remove oil cooler lines to get radiator out? I can't tell if it is one unit

[Tomguy]

Ron, fwiw, I couldn't get my 4.5's plugs out either. So when I did the heads I flushed it.

I know you should NOT have to do that but it does work! And quite well since you can actually spray the block down and suck it out. I used a shop vac with a small vinyl hose to suck out the water as I used a 2gal garden sprayer to clean every inch of the water passageways until the water ran clear.

Other than that, you'll be doing a LOT of "rinsing" if you use a flush and can't remove the block plugs. You DONT want that stuff in your system, and each side of your block holds at least a good gallon I'd say.

[meltedpanda]

are you saying you removed heads??
or just stuck a hose in the entry ports to rinse and then suck out?

[Tomguy]

I said when, not that I removed the heads to do so! I did the heads for "Fun" (experimental purposes) so it was something I did "While in there".

YOUR best bet might be a garden hose with the thermostat stuck open, and hoses off the rad.

[meltedpanda]

gotcha
I think I am going to remove thermostat after drain and refill with water , then run and redo process untill she runs fairly clear..... I will let you know

[nobby]

Originally Posted by meltedpanda

Do I have to remove oil cooler lines to get radiator out? I can't tell if it is one unit

I managed to split the oil cooler away from the rad on removal thus saving me from oil line removal.

It was a bear to re-install, though. I think I would remove as a unit if I had to do it again.

[meltedpanda]

will do, thanks for the heads up

[meltedpanda]

I drained radiator and removed for eventual repair, removed thermostat and flushed with water stream till clear.. Undid lines to heater core and flushed to clear there as well. Undid bypass hose and flushed till clear out themostat housing. Used compressed air to blow out the remainder, all I could get from any inlet or outlet was eventual clear water. I am in hopes I got the majority of the old green stuff out. Boy my hoses were in bad shape, especially the ones that I do not visualize often.
Hows this sound to you guys??

[nobby]

Replacing the hoses is fun!
Wait until you try the heater hoses. Fun Fun FUN!

[Lexxani]

I got lucky, I removed my T-stat and pulled the top radiator hose (highest part of the engine) and the radiator drain plug and hooked up the hose to the top rad hose (into the block) and let the garden hose run for like 10 mins. I say I got lucky because I didnt have any residual grime come out of the block. Later on i removed my heads (a separate job months later) and this confirmed my belief that my passage ways looked good as they looked 'virgin'.

I neglected to re-install the T-stat (87degreeC) because the engine ran way too hot for florida, now my cooling system stays at about 180degreesF. Ive had no ill effects from running w/o thermostat.

I refilled with the coolant from MB and distilled water. Beautiful!

[Gilly]

The problem you run in to by not having a tstat, is under extreme hot conditions, the coolant may not be staying in the radiator long enough to get all the heat out that the radiator is capable or removing. It's not like the coolant will ever come out "cold", but if it isn't regulated by the tstat, it can and will cause an overheat condition. Under the right circumstances I have seen this happen on fairly nice days, doesn't have to be a "scorcher" of a day, but usually it is. You are better off having a tstat.

If you didn't flush the block out with distilled water, you still had hard water in the block. I know the water in Florida is typically very hard and full of sulphur. Could have run a few gallons of distilled through the block before starting in with coolant.

Gilly

[LUVMBDiesels]

Melted,

If you are going to replace the heater hoses why not buy one of those Prestone flush kits, cut the heater hose going to the heater core and insert the tee fitting. WHen you are done, swap out the hose and save the old one for future flushes.