lt1slowz28

You either have a clogged passage or a bad hg/cracked head... mine did the same for a while. Would be fine until it got to operating temp hang for a bit then boil over... fix the issue while its not bad comparatively speaking.

93z383

iTrader: (-1)

Are you talking a clogged coolant passage inside the head? How can I go about testing and finding out if any of those 3 things is the problem?

So what ended up being your problem when you figured it out? If it's a clogged passage in the head, is there anything I can run through the engine to unclog it, or do I have to pull the head? Seafoam, anything like that? If the head is cracked, would it be one of the coolant passages that's cracked?

The car runs extremely strong with no smoke, smells, coolant consumption, oil consumption, or oil/coolant mixing. How can I figure out the problem....

93z383

iTrader: (-1)

Also I just changed the oil today, and there was a decent amount of metal on the tip of the oil plug. Maybe a good 1/16th of an inch of shavings clumped on the end, but the oil looked perfect, just typical dirty oil.

I posted this in another thread but I should also mention that since I did the coolant flush and pulled the knock sensor on the passenger side, I've been getting a code for KNOCK SENSOR LOW VOLTAGE BANK 2 (pretty sure that was it..). When I pulled the KS I dropped it on the ground because the coolant came blowing out super hot. I cleaned it up tightened it back in and put a small dab of dielectric grease on the connector before I plugged it in.

I don't get a check engine light, and the code does not pop up when I scan the car. I have to go in and use the "advanced DTC's" option on my scanner, then it shows up under CURRENT DTC, and also FAIL SINCE CLEAR DTC. 2 codes AIR related also show under FAIL SINCE CLEAR. No idea on the air codes........ But I'm thinking the metal shavings are from me busting the knock sensor last week and driving it a bunch, took several long trips and went WOT many times.

LT1FirebirdSLP

iTrader: (2)

You are definitely diving into more deeper issues here. I would say it is a plus that you don't have coolant consumption (no coolant entering combustion chamber), ruled that out. No oil/coolant mixing (no coolant crossing into oil galley or passages), ruled that out. No oil consumption (generally unrelated to high temps, bad rings, mechanical other issues), ruled that issue out. No smoke or smells.

My thought is that it PROBABLY isn't a bad head gasket or cracked head, etc. Did you install your coolant crossover? Steam pipe at the rear of the heads? Use any non-standard tubing/sizes for coolant? What happens if you use your heat in your car at idle? Cold/hot/warm?

If it is bad gasket/cracked head, and you have ruled everything else out, the only way to determine a small crack in the head is to remove it, strip it and magna flux (or equivalent) it. Bad gasket will be evident as soon as you get the head off. I know mine was screwed, when my builder took the heads off, you could see the shiny top of the piston that was affected, literally steam cleaned it.

Personally, I would start by replacing the water pump, a faulty water pump is cheap to replace, albeit a small PITA to do so. See if that helps your problem AFTER reading my previous questions and double checking all your hoses.

You'll figure it out, hang in there.

SS RRR

iTrader: (2)

I still think you have air in the system. I'd put a stock thermostat back in as well until you can get the fans adjusted to come on earlier.

lt1slowz28

could be as simple as a a clogged steam pipe.


nothing is easy about finding the solution an issue like this, at least until you start finding clues...


remember a bad head gasket doesnt always smoke, leak into the oil etc etc... it could just be pushing combustion gasses into the coolant passage.



or you could just have air trapped way back in the head causing these issues. either way the description you have provided about the steam and hissing. that in itself leads me to believe air is in there, either it's introduced as things expand, or it's just there and won't come out.

speed_demon24

iTrader: (6)

Have you tested the coolant for exhaust gasses yet? Or pressure tested it?

93z383

iTrader: (-1)

Nope that's what I was asking, how do you test for these things? Never had to before

Blind898

iTrader: (1)

Im right beside 93z383 on this one. Everything hes saying is the same with my car. My car will run at 190 np but idling it jumps up like crazy. Bleed the **** outta the car multi times to the point only liquid comes out now but with a cold start cap off you see bubbles raise to the top. Can only keep the cap off so long before it starts to boil over. Im gana try doing a compression test to see if any cylinders might show signs of a bad HG pushing gas into the coolant. How would you clean / test for a clogged steam pipe?

tom falco

I have a 96 with an electric water pump and 160* stat. My car runs at 160* all the time and never gets hotter. Have you radiator flow checked at a radiator shop. If it flows correctly you have a BLOWN HEAD GASKET. This is what is causing the excessive pressure in the cooling system. The cooling system can also be checked by installing a stant pressure checker. Start the engine cold with the tester installed in the radiator and rev to app 1200 RPM. If pressure builds on the gauge you have a blown head gasket. You can also check a blown head gasket with an emission machine or a block check chemical tester. Both of these methods checks for HYDRO CARBONS in the coolant. NOTE you cant flush a cooling system to remove scale. It is chemically fused to the radiator and if that is youe issue a new unit will have to be purchased. GOOD LUCK

great421

iTrader: (1)

OP - remember a 160 degree thermostat only opens at that lower temp; meaning that if your PCM has not been reprogramed to start your fans ON at a lower temp, then is is the reason for your "no change" condition.

SS RRR

iTrader: (2)

You can rent a pressure tester from an autoparts store. It's self-explanatory. Just don't pressurize the system more than 18psi. Take the plugs out, pressurize, note if guage starts to fall and how fast. Take plugs out before doing this. If pressure does not hold and you do not see any coolant on the ground, rotate the engine and see if coolant comes out of any spark plug holes.
I think you should start all over. Drain the block (both sides) and radiator and fill back up. Reason being is what you've described as of late sounds like a classic case of a cooling system with air in it. The entire cooling system takes approx 4 gallons. Open both bleeder screws and fill. When coolant starts running out of t-stat bleeder screw, close it. Ensure radiator is about half full and start engine. Have someone inside the car paying attention to temp guage as you look on into radiator fill. You should see the coolant steam return line start to sputter coolant back into the radiator. Keep adding to radiator to keep around half-full. Once there is a steady stream that's a tell tale sign the cooling system is thoroughly filled. Keep the top bleeder screw (heater core hose) open while doing this. If you close it, coolant will revert out of the radiator fill as it expands. Fill radiator the rest of the way up. Shut off engine, shut top bleeder screw, let cool and fill radiator again as well as reservoir to proper level. You may have to do this for a couple of heat cycles.
Start this process with cool engine.

tom falco

Thermostats are calibrated to CRACK TEMPS

Another words a 160* stat starts opening at 160* and is fully opened at app 165* +&- Normally with a 160 i program the fans to 175-180*

93z383

iTrader: (-1)

Yeah I was not the one to install the crossover tube or steam pipes, the original owner replaced the water pump and did everything, so I'm just trying to figure this out now after purchasing the car. I will have to try the pressure test and go from there.

I will also try starting the car with the cap off to see if air comes to the surface, haven't done that yet.

All I know is the hoses are all correct, the system is fully bled, and with the hoses off when I squeeze them coolant comes from each one freely...

AChotrod

iTrader: (17)

Check the hose running to the overflow tank. If its clogged it could cause your issues. Someone on LTXtech just had this problem and thats what it ended up being.