dville_gt

iTrader: (5)

Got a turbo charged 370ci 6 liter. dumPopped the stock #7 in June and built this motor. dumGot it back together and it was running hot (not puking coolant but creeping up to 230* and above). dumI am running a large dual pass aluminum radiator and 3k+ cfm fan so I should be okay. dumAnyway, I pulled the heads and had them milled as I was loosing some coolant and saw some aeration and figured the heads were probably to blame. Got it all back together and of course it is doing the same thing.

When I put a radiator funnel on it I get a lot of air/foam coming up into the funnel, and the level in the funnel keeps rising and rising the entire time pushing the water out of the funnel.

Car will run decently cool with AC off, but the temp creeps and creeps over 30 mins or so up to 215 and above.

When I let the car cool off it always seems low on coolant in the radiator but I can tell via a clear overflow hose that it is pulling coolant from the overflow as it cools, just not refilling the radiator completely.

I am thinking the water pump might be aerating the coolant which is reducing the cooling ability and displacing coolant which is why it is constantly low and running hot.

Any one seen a pump go in a way that introduces air into the cooling system as the motor runs but doesn't leak coolant out? I've pressure tested the system, leak down, replaced head gaskets, ran a few thermo combos including no thermo, burped/ bled it every way possible, etc. and still have issue.dum

LS1MCSS

iTrader: (18)

I'm thinking you have a leaking head gasket and are pressurizing the coolant system.

dville_gt

iTrader: (5)

just had the heads milled .007" and new ls9 gaskets

salemetro

iTrader: (5)

Just a guess....cracked cylinder? Maybe a warped block deck?

Have you done a leak-down test?

35thPewterZ

iTrader: (2)

i was just going to ask you if you had the heads resurfaced. really sounds like you have exhaust leaking into system or vice versa. we had a GM 6.0 block do the same thing right out of the box. fought and fought with it, finaly sending the heads off to get resurfaced and boom, it was good. might also check your small coolant tubes under intake. i havent heard of waterpump doing that, but not saying it isnt either.

dville_gt

iTrader: (5)

deck was checked when the block was bored .030 over. passes a leak down and when i had the heads off to get checked/plained none of the combustion chambers showed any indication of water.

dville_gt

iTrader: (5)

heads were resurfaced. have the 4 corner ls1 style coolant crossover tubes hooked up with no indication of leakage.

salemetro

iTrader: (5)

I suppose it's possible that one of the cylinders could be pushing pressure into the coolant system under the power cycle, yet not sucking water on the intake stroke. Highly unlikely....but still possible I suppose. Does the cooling system smell like exhaust when it's pushing water out? Maybe time to borescope the engine....

Man.....honestly sounds like you're doing a pretty damn good job of checking things....just throwing some ideas here.

dville_gt

iTrader: (5)

cooling system doesn't smell like exhaust at all and the foam is very clean. i've had combustion gasses get into cooling systems before but typically i see a dirty foam when that is the case. this is much more like air vs. combustion gasses (at least IMO). maybe wishful thinking however.

salemetro

iTrader: (5)

That's pretty friggin' strange. I wonder if it's possible that you're just fighting an air bubble in the system that won't bleed out...then it causes over-heating, and pushes water out? I fought a bad air bubble in my Miata swap, and had to jack up the front of the car on the passenger side to get it to finally bleed out.

Grasping at straw here....

dville_gt

iTrader: (5)

I appreciate the help either way.

I have a remote radiator filler neck on it that is clearly the highest point in the system.

I am using the 4 corner steam cross over that is tapped into the remote filler (highest point)

i fill through the upper hose, thermo has 3 small holes drilled in it, heater core is looped (not blocked)

ive got a big radiator, high powered fan, etc.

car does pretty decent with the a/c off (can get it to hover around 200*), but a/c on and/or low speeds make it start creeping. every time i check the coolant after it cools down it is down 5-10oz. i can tell it is drawing coolant from the overflow (i have a clear hose from the over flow to the filler neck), but it doesn't fill it all the way up.

no leaks on the ground and it passed a pressure test, leakdown, etc.

salemetro

iTrader: (5)

Throw me some more information about your car: swapped vehicle, etc.

Is is only overheating when you're driving down the road? Does is "Creep" up after 10-15 miles of driving? Or, does it over-heat at idle?

wssix99

iTrader: (5)

My first questions would have been to inquire as to the smell in the radiator and about a leakdown test. Since those have been answered, I'd start looking outside the core of the engine.

I wouldn't put too much stock in this since the system is intended to be pressurized. If you open the radiator while the system is trying to bring up the pressure and the fluids are expanding, odd things can happen.


This is odd. Even with air in the system, the car should still be able to cool down unless you are running at the edge with respect to how much heat the engine is putting out and how much heat the radiator/fan can push out. I'd also treat the thermostat as supect, ...but you should probably resolve the air issue first.



How old is the water pump, then? It could be the culprit here, especially if it has miles on it. Any signs of leakage from the weep hole?

dville_gt

iTrader: (5)

Ran the car with the cap off last night and didn't have any bubbles/foam at all, the coolant level rose (as to be expected) as the temps came up, but never any foam or bubbles.

Drove the car about 20 miles in town (not a lot of stops, but a few lights, mostly 30-50mph) and it never got above 196*, drove it home on the highway and never got over 198*.

This all sounds good except it was only ~85* out at that time and I didn't have the a/c on. If the A/C was on it would have been significantly higher and if I'd have had to sit at idle for a long period of time it would have definitely been higher as well.

The car has a powerglide so on the highway I am spinning around 3k rpm so it is tough on the cooling system to keep cool.

I talked to the guys at Griffin Radiators and they recommended their MaxCool dual 1.25" core 31x19 to replace my generic dual 1" core 28x19 unit. I am hoping the better designed radiator along with larger/longer cores will provide me the increase in efficiency I am looking for (but I'm not holding my breathe).

I can't imagine the car could make a 40-50mile round trip holding a steady temp if something was seriously wrong in the motor, however the disappearing coolant trick is disturbing. I replaced the clear hose I was using between my overflow and the filler neck on the off chance that the system was explelling coolant into the overflow, then drawing it back through the hose but getting air as well. Thus refilling the system with air and water. Might be dreaming though.

I went ahead and bought the larger Griffin radiator and it should be here tomorrow. We'll see how it works out.

Z28Drifter348

I know this sounds Crazy but try to see if the heater works while driving. If hot air comes and goes then you have a lot of air coming into the system and filling the heater core as your driving. When I started lifting the head on my duramax it didn't use any coolant or throw carbon into the coolant. it would build pressure in the system and leak the air into the overflow and then right out the overflow dump hose. Only sign that it went was it was in January and my heater blew ice cold. No power loss or any other noticeable symptoms. Powerstrokes are known for this as well. And i dont see why it cant happen on any gas motor if the head starts lifting. Good luck

wssix99

iTrader: (5)

I'd check the radiator again after you've run the car through a couple of heating cycles (to let any air work out through the overflow) and after the car cools down completely. If you have an air pocket in there, then you definitely have a problem other than the radiator.

If you don't have an air pocket, then that would point back to the radiator. (If your big problem is when the ambient temperature is up or the A/C is on, that would point to lacking cooling capacity.)

dville_gt

iTrader: (5)

no heater, heater lines are looped at the pump. interesting possibility, i don't see any signs that it's pushing a bunch of air into the overflow but i guess it could be.

i plan to check the level today when i get back from work. i know how full the overflow was yesterday before i went on a drive, so it should be that full now.

dville_gt

iTrader: (5)

I drove the car for about 45 minutes last night without it creeping up, went up to 198 a few times, then back to 194-196 so things are "working" but like I said it wasn't real hot and the a/c wasn't on. I've tried a few different thermostats in it now, the current one is a 180 with some holes drilled in it.

Pump is of unknown age. Replaced the one I got with this motor with one off another junkyard motor we have. So probably pretty old, but I can't see any leakage (and there doesn't seem to be a weep hole on the truck pumps, I examined the one I pulled off and there isn't one). I also sat under the car last night before, during, and after running the motor looked at the pump and every other place coolant could be going (including the oil and rolling the motor over with no plugs in it to see if any water came out. No sign of the water anywhere.

wssix99

iTrader: (5)

If you have an air pocket in the radiator, this will happen as a result. As the coolant expands, it will push that air through the overflow.

This isn't a good thermostat to debug with. Having too much flow, through those holes, could cause the system to flow too fast and not cool properly. (This is why cars can overheat without a thermostat installed.)


I'd expect there would still be one. You may not be able to see it behind the pulley. (It would be near the shaft.) Even if coolant can't get out, its still possible that air can get in. In the end, I think looking for the air pocket will tell you which way you need to go next.

dville_gt

iTrader: (5)

How would you look for an air pocket? I've tried filling it and burping it every different way I can think of.