1996 - LT4 - Cooling Issue
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,546
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From: Orlando FL
1996 - LT4 - Cooling Issue
Hey guys -
It's been a while since I've posted in here. Some of you may remember me asking lots of questions about my 84. Anyway, I still have it but have added another to the garage. 96 LT4 that was purchased with cooling issues and top end noise. I am pretty certain that at least one head gasket is blown without doing a leakdown. BUT because im not 100% I am asking the specific questions below -
Car starts, runs, heats quick and it also appears no water is leaking from water pump. There is also absolutely NO smoke from exhaust. It does however force water out of the overflow container. My question is - can this be caused by a blown head gasket? Keep in mind that there is no coolant in the car. It is pure water as everything has been forced out of the overflow. I have dealt with many blown gaskets, but none of which forced coolant out of the tank. A quick search on Google tells me HG failure can force the coolant out! SO I guess I was right. Looks like the heads will be coming off...
The top end noise I am hearing is pretty consistent with lifter/spring issue. I will be removing covers with in the next few days and inspecting. I will update this thread in a few days once I check.
It's been a while since I've posted in here. Some of you may remember me asking lots of questions about my 84. Anyway, I still have it but have added another to the garage. 96 LT4 that was purchased with cooling issues and top end noise. I am pretty certain that at least one head gasket is blown without doing a leakdown. BUT because im not 100% I am asking the specific questions below -
Car starts, runs, heats quick and it also appears no water is leaking from water pump. There is also absolutely NO smoke from exhaust. It does however force water out of the overflow container. My question is - can this be caused by a blown head gasket? Keep in mind that there is no coolant in the car. It is pure water as everything has been forced out of the overflow. I have dealt with many blown gaskets, but none of which forced coolant out of the tank. A quick search on Google tells me HG failure can force the coolant out! SO I guess I was right. Looks like the heads will be coming off...
The top end noise I am hearing is pretty consistent with lifter/spring issue. I will be removing covers with in the next few days and inspecting. I will update this thread in a few days once I check.
Last edited by quiksilver458; Sep 13, 2009 at 07:21 PM.
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
Using a block test kit, you can replace the pressure cap with the kit's cap. Then you draw air from the tank through the chemical tester. The chemical starts off blue but will turn yellow if exhaust gas passes through it.
NAPA Part number 700-1006 price ~$45
NAPA Part number 700-1006 price ~$45
Racer
Joined: Jun 2006
Posts: 408
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From: Elkton MD
1996 cooling
The LT1/4 runs hot. The normal operating temp (in traffic) is above the boiling point of pure water under no pressure.
SO, it is likely necessary to add 50/50 antifreeze and get a good cap (15psi) so the boiling point will be 260F - well above the likely 220-235F temp (not moving) when the thermostat opens (195) and the fans come on ~225F. Without the 50/50 mix and 15psi, the engine is a steam generator.
Even with the 50/50 mix and pressure cap, it requires 3+ hot/cold cycles and bleeding the air vent to get the air out of the system. Until the air is out, there will be lots of air/liquid moving back and forth to the overflow tank. And during this hot/cold cycling, do not remove the radiator cap.
Knowing the above, it's possible there's no blown head gasket. Not to say for sure, just the possibility. Checking for exhaust in the coolant is probably easier than adding the antifreeze, 3+ hot/cold cycles but it does cost more.
Good luck and hope this helps.
SO, it is likely necessary to add 50/50 antifreeze and get a good cap (15psi) so the boiling point will be 260F - well above the likely 220-235F temp (not moving) when the thermostat opens (195) and the fans come on ~225F. Without the 50/50 mix and 15psi, the engine is a steam generator.
Even with the 50/50 mix and pressure cap, it requires 3+ hot/cold cycles and bleeding the air vent to get the air out of the system. Until the air is out, there will be lots of air/liquid moving back and forth to the overflow tank. And during this hot/cold cycling, do not remove the radiator cap.
Knowing the above, it's possible there's no blown head gasket. Not to say for sure, just the possibility. Checking for exhaust in the coolant is probably easier than adding the antifreeze, 3+ hot/cold cycles but it does cost more.
Good luck and hope this helps.
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,546
Likes: 0
From: Orlando FL
Ok - So Autozone had the part in stock for the tool rental program. I went up there, rented tool, followed directions to run test but car is heating entirely to quickly. The radiator level was low enough to do test, but as car heated, it rose to high to conduct test. It began overflowing, and I turned car off. Could this be a sign of waterpump failure? I'd really like to do test, but am a little reluctant to conduct it with very little coolant in system. Would it mess up the test if I conducted it with very lil coolant? Directions say car needs to run at least 2mins for fluid to change colors.
Thanks!
Thanks!
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,546
Likes: 0
From: Orlando FL
Update - Pulled car out of garage for plenty of light. I started and idled car on driveway for about five minutes when I noticed a small puddle no larger than 3in by 3in directly under the car. A quick inspection of the water pump proved water is indeed leaking from weep hole. I will be replacing pump, thermostat and cap sometime this week.
I purchased the car last week with this known heating issue. I am hoping that the car was not overheated to bad creating head gasket damage. Wish me luck!
I purchased the car last week with this known heating issue. I am hoping that the car was not overheated to bad creating head gasket damage. Wish me luck!
