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4.5 (etc.) - how to best maintain the cooling system

583 Views 2 Replies 3 Participants Last post by  behind-bars
I'm finding some confusing information. Some have told me that if this engine has a weak spot, it is in the area of operating temperature management. The solution is to ensure that the cooling system is running properly.

My "new" 1990 SDV has 21k miles and 19 years on it. It is in near-new condition inside and out, with every mile and event documented including the five oil changes at the dealership. Original coolant is green and clean. Questions:

Should it be flushed?
What's the best coolant and ratio for a neverfreeze CA climate?
Does it make sense to add RedLine?
What are the mysterious "sealant tabs" that some have mentioned?
Should I add an aftermarket water temp or crankcase temp gauge?

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Probably no need to flush it.

Change the coolant every 2 years with a 50/50 mix of coolant and distilled water. Forget the Redline.

Go to the Northstar section and read t he sticky about the sealant tabs. Not sure if they where required in your engine, but I think so.

Not sure what you mean by "ADD" and aftermarket water pump. There already is one and you can't add more. An additional gauge is up to you, but not necessary.
I would flush the heater core per this thread

The heater core usually gets missed when people do coolant changes, I would make sure to flush it since the heater probably doesnt get much use in California and you want to keep it from clogging incase you do need it.

Just use a 50/50 ratio of the green stuff, I never use any "additives" like redline.

Their are gm tabs and bars leak tabs, both the same thing, they can be picked up at walmart or any parts stores, They are either brown tablets, about 6 to a pack, Or a tube that looks the same. Dont get any thing liquid, Only powder. All they do is seal little leaks as a preventive maintenance. the decal under the hood says they are necessary. Make sure to run the engine after adding them to circulate them so they dont just settle to the bottom.

I wouldn't worry about habitually watching the temp, just keep it maintained and keep an eye on it. P.0.4 is the temp readout if you want to see it. Press off+warmer till the codes finish, at .7.0 press "Lo" once then "Hi" 4 times till its at .0.4
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