filthy coolant reservoir tank

Anyone have any suggestions for cleaning out the rust on the coolant reservoir tank? I used vinegar to flush the engine but the reservoir is still brown inside. I am going to take it off for more access. Anyone else done this before?

Remove tank, drain, dry. Put in some sort of cleaner, and a bunch of ice. Tape openings. Shake a lot. Drain. It will be cleaner. If not clean enough, scuff with Scotchbrite, paint with satin black Krylon Fusion. It will look factory like on the Corvettes. I did this on my SS years ago, along with the washer tank. Really cleans up the engine compartment.

If interested, still available new. 12528777. Usually the best price can be found on E-bay.

FYI, It's on sale at gmpartsdirect.com right now for $79.38.

Thanks, I didn't think the part was available.

I can say a soak in pure vinegar does not work well.

frederickflintstone wrote:

Thanks, I didn't think the part was available.

I can say a soak in pure vinegar does not work well.

The ice trick works well, but use crushed ice. Gets in all the corners better. Also, I've have good luck with Purple Power cleaner.

-Mike

Put sand/ gravel in it, your cleaner of choice. Plug all holes.strap it to the wheel of your lawn mower. Cut the grass. Tumble clean. It works great for old metal fuel tanks 
 Wear your ear muffs !

"Put sand/ gravel in it, your cleaner of choice."

Not too sure about the effect on the level sensor.

Rev Bob wrote:

"Put sand/ gravel in it, your cleaner of choice."

Not too sure about the effect on the level sensor.

level sensor is shot.

Time for a new reservoir.

The brown goo you're seeing might be the original dexcool/stopleak mixture that GM added at the factory 22 years ago. People way more skilled than me have thrown out expensive radiators caked with this stuff because they couldn't find a solvent that could get it off.

Back in the day I used the fine gravel/sand at the end of my driveway and just shook the daylights out of it. It got a lot out but not all. The lawnmower trick is probably more effective. The float switch worked just fine after. Took awhile to get all the rocks out though.

I have muriatic acid in it today I put it in last night and the fluid was brown this morning a lot has come out and I expect more. Tonight I will flush it and install regardless of the outcome.
the car will be stored I n a few weeks so a new reservoir may be added to the list of things I would “LIKE” to do to the car over winter.

Muriatic acid worked well. It also cured the low coolant sensor problem!
I also pulled the Knock sensors before I filled it back up.
I did an oil change while I was under there, but now my service engine light is on.

I cant remember if this vehicle is OBDII or not.

OBD1

silverfox103 wrote:

OBD1

Is the plug the same? can you kill the light with an OBDII reader?

""Is the plug the same?""

No.

FWIW after all this and putting $25 worth of antifreeze in it, I now have a coolant leak that appears to be coming from the waterpump area.

I will be parking the vehicle early for the season and fixing it later.

But the good news is, you have a clean tank!

Tom

""coolant leak that appears to be coming from the waterpump area.""

Check the pump attaching bolt tightness before doing anything else.

Now that you mention it Rev Bob, doesn't one of those bolts have to be sealed?

Tom

Yep. Lower bolt (retains fan pulley bracket if towpack), passenger side should have thread sealant.

My guess is that after 23 years, 162K miles, and all the harsh chemicals I have put in trying to “clean out” the system, something has to give. When I have time and space to put it on the hoist I will do my best to determine the cause, but likely I will be replacing the WP all hoses and belts ETC.
it would have been parked at the end of the month regardless due to the snow.

Too bad no before and after tank pics?

Andebe wrote:

Too bad no before and after tank pics?

To be honest nothing was cleaned on the outside and I doubt the translucency was improved much. But it is nice to see less brown inside.

I have HEARD, that putting a bunch of ground coffee in a crummy coolant tank with some water will clean them well.

It also kind of makes Cold Brew, but I wouldn't try it. I heard about this from the SAAB 9000 community back in the day.

FWIW I didn't even put a battery in it this summer. I have been driving my corvette and have not wanted to spend the money for insurance and a waterpump to drive the wagon. I need to look into collector car insurance as most all of my vehicles have suffered from lack of use.