97z28k&N

Hey all, I decided to finally tackle the replacement of my heater core due to no heat (and winter approaching!). I bought a heater core off of ebay for $40. It is after market but the design is almost identicle to the stock.

I attempted to change it yesterday...

I decided to flush the old heater core to get the crap out of the hoses before I put the new core in. I could not get any water from the hose to go through the hoses. It was near impossible. I gave up and just let the hoses drain by themselves.

I then tried to remove the heater lines from the heater core.... which was damn near impossible. I FINALLY got them off after about 90 minutes.

Getting the old heater core out and putting the new one in was a breeze. The only problem was, the heater core's aluminum tubes (where the rubber hoes connect) were slightly shorter than stock. I BARELY had the inlet tube on, but without the clamp (which i destroyed while removing). I got all other hoses on and clamped just fine.

I then poured some 50/50 "add to any color/ all makes+ models" coolant in the radiator to top it off. I then proceeded to turn the car on and add more coolant to the flowing radiator with the heater hose bleeder open. Some air came out but quickly became a flow of coolant, so I closed it.


I figured the car was good to go, so i tested the heat, which WORKED!

I decided to let the car warm up to see if it would cool itself down. I had the A/C on MAX because i figured the fans should come on and if the coolant was filled properly, it would in theory stay at 180*.

The engine started to get hot. FAST. The fans never came on and the temperature gauge was right below the red zone. I was about to turn the car off when all of a sudden, that unclamped heater core intlet hose blew off, producing a giant steam cloud. I shut the car off within seconds.

Why didn't the fans ever come on? Was too much air in the system? I only opened the one bleeder screw on the heater hose for a few seconds.

Side note- quite a bit of coolant came out when those heater hoses were off. like a half gallon.

side side note- I had the car towed to be looked at because I'll be honest, I have never worked on ANY cooling system so i am not that comfortable with what I'm doing. I've been relying on a shop manual and the internet for everything I have ever learned about working on this car.

shoebox

More than likely air was still in the system. That causes a rapid rise in the gauge because of steam in the head. The fans don't come on because the sensor in the water pump is not seeing as high a temp because there is more liquid present. If you slowly fill the system with the bleeders open, most of the air is purged. Your hose blew off because it was not clamped on well enough.

97z28k&N

Thanks for the reply. I bought wormgear clamps and used those rather than the difficult stock ones.

Also, a worker at advance auto parts told me that mixing 50/50 green stuff with dexcool is a bad idea over time and will cause jell to form. Is this true?


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87DJP2001

Good advice... DO NOT mix them.

mrmint69

Prestone can be mixed with any color. You should drain as much of the old coolant out and adding that should be fine. I usually flush the car with water to get as much of the old coolant out, but make sure you account for there being water in while adding new. Disconnecting the lower radiator hose allows a good amount of the old coolant to drain. Just check the mixture percentage later to make sure it is not to weak or strong. There are lots of good threads on proper system bleeding with a search. Most of this is for future since your so far along.

Injuneer

To drain the system completely, use the two block drain plugs (one of which is the knock sensor on the passenger side). Hard to get to, but worth the effort. There's a good chance that any solids buildup in the heater hoses in now circulating with your coolant and plugging things up. You should have flushed them after removing the heater core.

97z28k&N

well im not done yet...

apparently my radiator is cracked. it wasn't cracked or leaking before I brought it to this repair shop. they are telling me "there is too much sludge in the radiator and it probably cracked from overheating". IT NEVER OVERHEATED!

They are trying to charge me $644 to put the new one in.

I think i'll have it towed back to my house and figure this whole thing out myself, and really learn about the cooling system.

Sound reasonable?


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mrmint69

Half that price would be what I would expect to pay. Not a hard job at all.

97z28k&N

I called him back an hour ago, I talked to the man who worked on my car. He told me that there was a lot of rust in my block. He said that reasonable thing to do would be to pull the freeze plugs to get it all out.

this seems like wayyyyyy too big of a job. I'm afraid I might be looking at a new car....


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Injuneer

How did he determine there was excessive rust in the block? Did he use a boroscope?

97z28k&N

he didn't say. I could ask on Monday but they are closed today. I told him I will pay the $100 for flushing the system but I'm changing the radiator myself. I'm just going to get one from the local camaro recyclers (it's weird, they only scrap 4th gen camaros...) that looks pretty clean inside. i'll clean it up a little more but it's going on the car.

is the rust THAT big of a deal? I would assume it was already running through the system before the heater core was changed. It stayed at 180* every time it was moving or the fans were on.


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mrmint69

I would be careful since you really have no way to know if he even checked. They will tell you the easy stuff, thats expensive is always "needed". Flushing an engine is pretty simple and $100 seems like way to much.

97z28k&N

he didn't just flush it; He also adjusted the heater core's position and finished putting together the dash.


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shoebox

No, that is not true. However, IMHO, It is better to stay with one type of coolant or the newer "mixes with all types" stuff.

97z28k&N

I added the "mixes with all" stuff. Right now the car is at the shop with all water and no coolant.

I was going to pick it up tomorrow and replace the radiator. Can I put in a non DEX-COOL antifreeze in like prestone 50/50 green stuff?

How do I drain all of the water out of the system (to achieve that perfect 50/50 concentration)


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