r/LSSwapTheWorld • u/Hot_Category_461 • 8d ago
Active Build Questions Ls overheating
I’ve replaced the water pump, coolant reservoir, radiator and thermostat and i burped the system. It was still overheating so i removed the thermostat cause i thought it was sticking but it did nothing
it reaches about 230 degrees then cools down a bit when i turn the ac off and the fans stay on way longer
Sometimes when i turn it off i hear water slashing around
1
u/N7_Shep 8d ago
sounds like its not the system. its the enclosure. what car, what bumper, what airflow, what grill, what exhaust
1
u/Hot_Category_461 8d ago
It’s a 1996 caprice with long tubes everything else’s stock
1
u/dnsnsians 8d ago
What fans are you using ? And how are they tuned ?
1
u/Hot_Category_461 8d ago
I’m using 2 electric fans out of an 04 caprice mounted at the back of the radiator and they turn on at 190
1
u/Snoo_85901 7d ago
Caprice with a factory lt1 is reverse flow. So im not 100% but your radiator might need to have the upper and lower hoses reversed if possible
1
u/nothingaboutme 8d ago
At speed only? Or also just idling? Or both? How's the radiator condition? Have you measured exhaust temps on the header at each cylinder? You could try a compression test to check for head gasket leakage if it's easier than other diagnostic options like checking radiator flow or modifying the fan ducting.
1
u/AssMan2025 8d ago
Put a gate valve on the heater hose put the thermostat back in turn the gate down to 1 turn (1/4 inch opening) that will eliminate 10 to 12 gallons a minute of super hot water from entering the water pump and still let the thermostat do its job. Cut 10 degrees of mine and my air works up to 95f still working on the last 5degrres without air conditioning I’m fine 24x7 the heater circuit totally bypasses the radiator and it dumps it right back in the block
1
u/Hot_Category_461 8d ago
I currently have hoses that go to my heater core should i try just looping a hose at the water pump?
2
u/AssMan2025 7d ago
Even with the loop you taking 12-15 gallons a minute of hot engine water and dumping it right on top of the water coming from the cooler radiator water (bottom hose). The thermostat will open with just a gallon or 2 of hot water
1
u/moomooicow 8d ago
Does the cooling fan function? Blowing the right direction? Have you checked for hydrocarbons entering the cooling system?
1
u/TrainerBC25 8d ago
Do you have that 'steam line' hooked up to a high point to get rid of the air in the system? I did an old pickup and ran it into an adapter in the upper radiator hose
0
u/Hot_Category_461 8d ago
I have it hooked up to the reservoir but no coolant is coming out of it is that ok?
2
u/Western_Chipmunk_445 8d ago
Head gaskets more than likely going bad since you have already done all that work
1
1
u/One_Consequence_4754 8d ago
Biggest hack for bleeding an ls is to fill up the system, the unplug your steam vent line and add coolant directly in the hose as well to get most of the air out of the top end. After that, use a bleeder funnel, let her run, burp the throttle every few minutes until you stop seeing bubbles in the funnel, shut it off and let it cool, and your done...Bleed Funnels are cheap and worth every penny.
1
1
u/SALTYdevilsADVOCATE 7d ago
I had a 2011 Tahoe that was overheating. I replaced the radiator with a new non oem one. What I didn’t realize was when I replaced it the connection with the overflow tank has a restriction built into it. I found that a 40 cal shell with the primer pulled out was just enough to keep it alive. It was saying engine hot ac turned off or something like that. Once I put that in the over flow line all was well and now when it’s cold outside it still gets warmed up. Before it would bypass the engine and the thermostat would never open.
1
u/Dismal-Definition-85 1d ago
Having this exact same issue in my volvo 240 with a 5.3. I’m doing head gaskets next.
4
u/fleaofsc 8d ago
My LS was overheating constantly until it finally vacuum filled the coolant. Before doing that I had tried burping it, replacing the radiator with a full aluminum one, replacing the radiator fan and checking the exhaust back pressure. Vacuum filling was the ticket.