Changing coolant

[steveunpwned]

Hey all,

I purchased my 99 GMQ about a few months ago, and I don't think the previous owner ever changed the radiator coolant. It's a little below the cold fill line, and I was thinking about adding a 50/50 mixture in to top it off. Currently, it is a dark brown/red color.

I was told my several mechanics that flushing the radiator and hoses after never doing so, with 160,000 miles on it, would probably cause a lot of problems with debris and other corroded material getting inside the head gasket and block.

What does everyone think?

[Grandmarchris]

Definately change it a redish brown means that there is rust in the coolant. As for cloging the water jackets in the block/heads I woudnt worry about it. I would take it to a reputable shop because the radiator tank and petcock are made of plastic and could break or strip.

[steveunpwned]

Thanks so much for the response! I will definately look into this because I'd like the car to last awhile.

[Rizzo]

I know next to nothing about this as I have never had mine done GASP !!!

But I have heard you can have them pull the heater core lines and run their machine from that, I personally would avoid an increased pressure flush thru a 160K heater core.

[steveunpwned]

Thanks for your input 97cv
I talked to my major repairs mechanic today and he recommended I at least change the fluid without a high powered flush, just a basic drain and refill. I don't think he'd say that just to get some money, business is good for him now, but I suppose he would always want to make it better....

What color is your coolant 97? Mine is a mixture of dark red and brown. This is alarming me, and I'm still afraid that if I do a basic fluid change I'm going to see more problems down the line.

[Rizzo]

A low pressure drain and you should be OK.

Please if you listen to anything listen to this.

Failure to change the coolant will have negative effects on your HEAD GASKET. This is NOT something you just wanna put off. I (may) be paying the price for such foolishness my self.

If you wanna do a really low pressure, Get the kit from XXXABC-Autoparts. It will have a garden hose fitting. Turn on your garden hose and experiment with what pressure you feel comfortable with,Use the heatercore lines ( Far back passenger side of maifold ) and get it out.

[87_crown_vic]

have the car running when doing the garden hose flush way. that way it can heat up the engine and open the thermostat to allow it to pump the crap out. i would let it run like that for about 10 minutes or so with hose running into the system and engine running to allow to flush out. after it flushes out, shut car off, reconnect stuff and drain system. easiest way to drain is by opening radiator cap and removing lower radiator hose. after its empty.... make sure it is ready to be filled. add the coolant water mix to system leaving cap off, have engine running, and add once thermostat opens. you will know when thermostat opens up due to the coolant mix dropping in radiator with engine running.

when i werked at a regular shop we had a machine that connected to the upper radiator hose and the other end to the radiator.

[steveunpwned]

Thank you so much, I'll let you know how it goes!

[steveunpwned]

Kk guys and gals...I've been waiting for my tech buddy to get a chance to do it the garden hose method that 87 suggested, but he's been super busy lately, so I called up a local radiator shop this morning. For $90 bucks they'll use a low pressure flushing method to clean out the radiator and hoses, and fill it back up. I'm going to swing by their garage tomorrow morning before work to talk to them.

I'm so afraid of doing more harm then good to my 99 GM. But seeing a rusty colored coolant sitting in the resevoir doesn't make me feel good either. I keep thinking of the other advice I've heard from mechanics saying that I'll need a new thermostat, water pump, and at worse case, a new head gasket or block

I just want the car to last awhile and all the fluids be how they're supposed to be...