Problem:

I personally checked the engine fluids yesterday for the first time in probably a year. The coolant looked like reddish orange mud in the radiator, and the level was a little low. My first thought is that some guy at a dealership topped up her overflow tank with DEX-COOL instead of the green stuff during one of her dealership oil changes, and it fouled up the entire system.

My sister took the car to her regular mechanic, and he said that there was so much rust in there that he just drained it and refilled it and recommended we have it drained and refilled every 3 months. He didn't know why it started rusting so quickly.

He said: ultimately, my sister needs to get another car because the engine block is rusting on the inside. The mechanic recommends getting rid of the car or getting it restored. This could end my family's ownership of this car since 1995... which hurts all of us since we have put so much effort towards keeping the car perfect (or so we thought).

Background:

December 2005---72,462 miles: The coolant was checked by me, it looked great. It would leave a lime green drip on the garage floor every couples of days, but it was not low.

December 2006---~75,000 miles: Coolant level was fine despite continued drip every few days, but there was a little bit of "peanut butter" on the tip of the overflow's dipstick. Since the car was still leaking a drop of lime green coolant every few days, my dad and I drained the old coolant out and removed the old hoses. We changed all of the hoses (except the ones that were changed in 2002 because they looked good), rinsed the system with a garden hose, and put in the green 50/50 mixture it's supposed to have. Air was bled out of the lines that night and the next morning.

---just regular oil changes were done during 2007 and the first half of 2008---

October 2008---8x,xxx miles: The coolant was flushed and changed with the 50/50 green type. This was done by my sister's regular mechanic who said the coolant didn't look that great and it was time to do it. I don't know what the condition of the coolant was as I never saw it. He didn't mention rust.

---just regular oil changes were done during the rest of 2008 and the first part of 2009---

March 2009--85,731 miles: The car went to get an oil change at a Chevy dealership and the receipt states the other fluids were checked and were check marked "ok" on the Goodwrench checklist thing that came with the paperwork. No mention of rusty coolant.

June 2009--86,492 miles: The car went for an oil change at a Pontiac dealership and the receipt states the other fluids were checked and there were no problems. No Goodwrench checklist. No mention of bad coolant.

---just regular oil changes were done during the rest of 2009 by the regular mechanic---

February 15, 2010---90,563 miles: Car went for an oil change at the same Pontiac dealership as mentioned earlier, they did the Goodwrench checklist thing and it has the coolant level marked "ok" and the engine cooling system marked "checked and ok."

February 21, 2010---90,5XX miles: I replace the dirty air filter and worn out windshield wipers for my sister since they were mentioned on her Goodwrench report. Since she hadn't driven the car in about 12 hours, I checked all of the fluids to see the condition and to see if they put enough oil in during her oil change, and to my HORROR, the coolant not only looked like it did in the above pics, but it was very, very low!

What in the world should we do?

It seems so ridiculous and ironic that a 90k mile Z28, that has been garaged indoors its entire life with us in New Mexico and Texas, would be rusting internally. It's just a complete shock. It's even more shocking that these last three dealerships didn't notice the rust forming!

We'd ideally like to keep the car, without undergoing a complete restoration at this point. What can we do?

Obviously the first thing I need to do is replace the rusting radiator cap.

But what would you guys suggest short of a very expensive restoration of the engine block, heater core, and radiator?

 

Honestly, I would pull the engine inlet and outlet radiator hoses, hook a garden hose to it and run the engine for several minutes at a time letting the garden hose flush some of the rust out. Then do the same with the radiator in the loop.

If the radiator is clogged, throw a new radiator on it.

This is only how I would do it on my own car that is 15 years old and worth a few thousand dollars. I have never personally had this problem, but have seen other people do this with no apparent problems afterwords.

I would just do that and keep an eye on the temp gauge for any problems.

 

Adam, does the hose go in the top of the radiator? Can you detail this process a little bit more? I may have a lot of posts, but this is all new to me, so explain it like I'm a newbie please.

I live in an apartment complex, so I'd have to do this somewhere else to do that...

I just asked my sister, and she says the car has never ran hot, which is kind of... surprising...

 

http://shbox.com/1/4th_gen_tech2.html#radflush

Note: Be sure to keep the opti-spark as dry as possible. I typically cover the opti with a yellow trash bag anytime I'm working with water in the engine bay. (Cleaning, Coolant Flush, etc.)

 

Well, I checked our mechanic's work after the car cooled for several hours and he did a very nice job. The overflow tank has a bit too much in it, but the radiator has a bit too little in it. I suppose it'll even out...

He managed to get almost all of the dried "mud" off the dipstick somehow and everything is nice and green in the radiator. Still some rust, and I suspect the radiator cap would benefit from being replaced. It seems to hold pressure, but I don't have to press down on the '95 one barely at all. It's obviously rusty too, which isn't helping the situation.

I opened the bleeder valves. I don't remember if the car is supposed to be running when you do that or not, but it wasn't when I did it. The top one didn't hiss or do anything. The bottom one by the throttle body dripped a couple of times. Of course, I did this after taking the radiator cap off, which hissed. Maybe 1am mechanic work without my Haynes manual isn't the best course of action...

 

There are many different metals in a stock cooling system and two distinct permanent anti freeze types. When interchanged and incorrectly mixed the result is blockage. Eventually the radiator will fail and it should be boiled out under pressure at a radiator shop. Or just replace it. When it fails you will be on the road and notice a spike in the temp guage....then a blast of steam out the back of the car reminisant of a rocket reintering the atmosphere...it happened to me with my 95 Z28. Luckily, I was near a place to fix it. It may be time to replace it all.

 

hey man my camaro looked just like this. i just pulled off the water pump and stuck a garden hose in the passages the water pump connects too. i ran it for joke 30 minutes and all the rusty crap came out. dont be fooled, your car is not rusting from inside out and whoever said that is an idiot. i've seen thousands of old cars and they have NEVER had any rusting from the outside in. that is truly the most idiotic thing i ever heard lol.

 

I love you, thanks for that information!

 

just remember the cars old. its gonna have weird stuff happen to it.. everyones car is different. if its running good, and not knocking, dont listen to any mechanic. its your car. you know what goes on with it when it gets drove. a mechanic can only assume. Just don't listen to any rusting from the inside. also, as a side note, if it were POSSIBLE which its not lol you can get a used LT1 off craigslist for less than 500 cash