LS-coupe cooling saga continues :(

[shumpertdavid]

Really only an issue with a/c on, a/c off it can stay cool (not thermostat temp cool, but not 230*)

At minimum, cooling system temps will usuall run a minimum of 15 degrees above advertised thermostat temperature. 160 will usually run in the 175-180 range, 195 will be in the 210 range. Gm cars stock are setup to run in the 220-225 range on a lot of vehicles. From v8 camaros to grandma's 3800 buick.

[dville_gt]

So does it only over heat with the AC on only? Is your lower coolant hose in good shape?

Lower hose is brand new. 1.5" x 1.75"

Had to look through a million hoses to find the right bend/size



Really only an issue with a/c on, a/c off it can stay cool (not thermostat temp cool, but not 230*)

[MstangsBware]

So does it only over heat with the AC on only? Is your lower coolant hose in good shape?

[dville_gt]

radiator dimensions are 28x19x3 double pass with 2x1" cores.

[dville_gt]

Oh, and coolant cross over pipe is capped at the back (stock) and then the front two ports connect (stock) but instead of running to the radiator I drilled/tapped the waterpump housing and have it going back there (same way the guy with the turbo gto has his).

Haven't seen any evidence of a blown h/g, no smoke, no bubbles in the coolant, no milkshake. I know it is still a possibility, but doesn't follow any of the symptoms I've had with previous blow h/g's

[dville_gt]

Wow, thanks everyone for the replies. I added a bleeder valve to the upper radiator hose, and while it doesn't look great, it is functional until I can find better upper radiator hose solution. So I tried to purge the air, ran the motor until it got hot enough to push coolant out the bleeder (radiator cap on), let it cool down, pulled the bleeder, ran it until it pushed coolant, let it cool down, then pulled the bleeder and filled the remaining (small) void that was in the upper until it was full then capped it.

Went driving around, seemed to do a lot better at first, sat around 200 for a long time, then it creeped to 210 stayed there for a while, cruised on the highway for a few miles, stayed 210, got off and idled for a while and it slowly climed up to about 230 again.

Here is the upper with the sleeve I tapped and put a plug in:



Belt routing has been corrected:


I do have gaps on both sides of the radiator that could be causing the problem:




Plus there is a small gap between the condensor and radiator that is not sealed off at the top:


And the fans are stock f-body (small modification to get them to fit to this radiator, they seal to the radiator pretty good, no gaps:


Temp readings are coming from an autometer gauge and hp tuners logging the ect sensor, both are pretty much identical.

Car shows no signs over overheating, but I never let it go past 230*

Going to pull that plug and see if maybe some air bubbles were trapped and the first series of purging didn't get them out. Gotta let the car cool down.

Going to also try to source an air dam and make some plates to seal the sides of the radiator. Hopefully there were some lingering air bubbles?

[Txstang1]

Didn't read all the posts, however...

I had a similar issue with a car I owned in the past. Ended up being a head gasket that was popped. It was blowing exhaust gas into the cooling system.

Fire up the car when its cold, open the radiator cap. Look in the radiator. If you get tons of bubbles, you have a blown headgasket.

you wont always see it though. block test FTW! best money spent for diag i think

I've had a blown head gasket before and was finally able to detect it by condensation/water coming out the exhaust.

[greenbullitt]

Didn't read all the posts, however...

I had a similar issue with a car I owned in the past. Ended up being a head gasket that was popped. It was blowing exhaust gas into the cooling system.

Fire up the car when its cold, open the radiator cap. Look in the radiator. If you get tons of bubbles, you have a blown headgasket.

you wont always see it though. block test FTW! best money spent for diag i think

[Dacotua]

Didn't read all the posts, however...

I had a similar issue with a car I owned in the past. Ended up being a head gasket that was popped. It was blowing exhaust gas into the cooling system.

Fire up the car when its cold, open the radiator cap. Look in the radiator. If you get tons of bubbles, you have a blown headgasket.

[greenbullitt]

and to add to this, does it do the same with ac off? as mentioned earlier

[46Tbird]

Don't cut the front bumper on that car. That isn't how a modern car gets air for its cooling system anyway. It scoops it up at ground level using a dam, forcing it in front of a sealed radiator, and there should be a pathway for the heated air to exit the engine compartment.

Air has to go into, through, and out of the radiator to cool the coolant. Those giant gaps on the sides of the radiator are going to let air pass around the edges instead of going through. Path of least resistance and all that.

But let's start with the basics. First, is it actually overheating? I have a cheap-dick Equus temp gauge in my wagon that sits on 100 when the car is ice cold and it runs down the highway showing 270... which is actually 170. When your car is "hot" is it really doing funky stuff, smelling hot, datalogger showing hot?

If yes, then does the car begin to overheat when it's sitting still with the hood open and the fans running?

If yes, then while idling and overheating, is the coolant in the radiator hot or cold?

[kingjason]

Also looking at that fan set up it looks as if its not really forming a shroud over the whole radiator. You look like you might be loosing 10-15 percent right there. Thats not a flex a lite either now that I am eyeballing it I think. More info on the fans please.

My Galaxie had an electric fan on it that was ok when it was 90 out and held it around 190 or so, The other day when it was 110 out it was sliding up into 210-220 range at lights and wasnt really cooling down while rolling. Slapped the shroud and a fan on it a walla 180 holding steady the other day when I was driving or stopped.

[kingjason]

How big is that damn condensor in front of it? That looks like one problem. Then go get you a two speed taurus fan set up for it for 50 bucks and try it. That flex a lite may not be pulling enough to cool it. The Tuarus fans will pull a small bird thru the front of the radiator. I need more pics but it looks also like you have blockage on the sides from the core support.

[MstangsBware]

he said it gets hot sitting still or moving. an air deflector will not fix his problem

Gotta ya..I missed that part of the topic....I went back and read the first Thread but am unsure on some things as there are mixed replies...Does the car over heat with the AC off also or only with the AC on? What does the temps get up to while just sitting at idle?

[NoClassic]

I cant see cutting the bumper or adding a deflector doing much for stationary cooling. If anything just make some panels to fill the gaps between the radiator support and radiator/condenser sides.

There has to be air in the system or the pump itself is bad. A very small amount of air in the system will decrease the systems cooling capacity dramatically. I went through the same deal with my swap and it ended up being a used pump I cheaper out on.