jmdale1984

iTrader: (6)

Ok guys, I really need some help here.

My car is at 193k miles, and a few weeks ago my radiatior tank cracked. The waterpump had been making some noise, so I decided to replace them both a few days ago.

When I refilled the coolant system, I started by filling the upper radiator hose as much as I could, then filled the radiator while I let it set and idle. I seemed fine when I let it idle with the A/C on, so I took it for a drive. Didn't make it a mile before it was overheating like crazy.

So after hours of inspection, and attempted bleeding, I decided that since the radiator tank wasn't even getting warm (except right by the head/TB bypass), it must need a new thermostat. Replaced that, and it did not help at all.

It seems to only get water to the heater core while running at higher RPMs (1500+), and the bypass hasn't yet returned to being a steady stream of water, just intermittent splurts.

While idling it takes a long time to overheat, yet as soon as it is raised above +1000 RPMs, even if only for a second, it will follow with quickly rising engine temps.

Here are the things I've tried:

Remove Temp Sensor to bleed (not running)
Remove heater hose to bleed (not running)
Bleed air out of Upper Radiator hose, water pump end (while running)
Removed and inspected new water pump
Added water to head/TB bypass hose
Put on an upward slope, and ran it
Many heat cycles

It is now heating slightly at idle, but not as much as it should. It is moving water now, but is still overheating. The Upper Rad. Hose, Lower Rad. Hose, and both endtanks of the Radiator are getting too hot to touch. This seems to be an improvement, however, it is still overheating just as much as it was before. Before I began this repair, it never overheated.

Nothing seems to be working here. I'm lost and I want my car back, someone please help!!!

CRAGER

Take off the radiator cap, while the cap is off start the car so it can bleed. Thats how I've done it a few times. Plus I never really see anybody taking off this hose or that hose to bleed it.

And how about the fans, are they working?

Peace,
Craig.

jmdale1984

iTrader: (6)

Fans are working (though I wish they'd come on at a lower temp). I've had the rad cap off for many of the warmups I've already done. Seen a lot of air bubbles the first few times, but there's not really any coming out anymore.

CRAGER

Did you leave the cap off while the car came up to full running temp? Sometimes it takes a while until the t-stat finally opens up, then it starts to gulp and water level drops way down. Then add more.

Peace,
Craig.

jmdale1984

iTrader: (6)

That was one thing that threw me off.

It got up to running temp (~209 on my dummy gauge), while I was filling it with the cap off... but the water level didn't drop, it only kept rising. As I've filled it several times, it's done the same each time.

CRAGER

Sounds like it's stopped up and the pressure is making the water level to rise.

Does the lower hose swell up? And are you sure both fans are working?

You could always test the t-stat in a pot of boiling water. The water pump is new, but you never know. The impeller might be broken, and therefor not pumping anything.

Peace,
Craig.

jmdale1984

iTrader: (6)

Already took apart the pump and inspected it (a mechanic I know mentioned that he'd gotten an LS1 pump with the impeller put in backwards once). The t-stat is brand new, and the old one wasn't that old. Neither one of them changed anything.
I'm sure that both of the fans are working, too.

You're right about it sounding like something's stopped up, I just don't know what would be.

I just warmed it up again though. I pulled the cap off while it was still hot enough to have the t-stat open, and it took about a gallon that way. Started it back up, and it overheated a little, but as soon as the fans came on, it stopped and held it's temp, but didn't get any cooler. Before it has just skyrocketed until I shut it off.

I'm sure it's still far from driveable, but definitely a step in the right direction.

jmdale1984

iTrader: (6)

Also, the heater seems to be working normal now, which may be the reason it's cooling better (I've been running the heater constantly).

jmdale1984

iTrader: (6)

Cross that out... the heater's not working right. However, it is in the beginning stages of actually cooling itself. It'l overheat quckly while driving, but it's starting to recover it's temp when it returns to idle.

Quickin

With your mileage, your problem could be exactly this, if everything else in the cooling system is fine like you say. My engine slowly over a few month period started overheating worse and worse, I checked to make sure everything was operating properly, and this is what cured my problem and it runs cool as a cucumber since.

https://ls1tech.com/forums/general-maintenance-repairs/491395-overheating-solved-you-d-never-guess-how.html


.

Ntimid8r7

iTrader: (9)

its funny you found that^ My Blazer was suffering from overheating and when I pulled the radiator it was 80% clogged up with ****. A/C condensor was fine but the rad. took the brunt of the mess. I have some pics of it. It is amazing what gets in there and stays!

jmdale1984

iTrader: (6)

I found the problem. It was a bad water pump casting from Autozone. It was cast incorrectly and refused to flow properly. A new pump solved my problems immediately...

Moral of the Story? F%^K AUTOZONE!!!!!!

CRAGER

LMAO! I don't care for them much either.

But glad to hear you found what was wrong, and thanks for posting!

Peace,
Craig.