How to make sure its head gaskets?
Thread Starter
Teching In
Joined: Aug 2009
Posts: 37
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From: Manitoba, Canada
How to make sure its head gaskets? On my 96 lt1 i got a low coolant light the other day but it wasn't overheating or running any differently so i got home let it sit overnight and opened the cap in the morning and sure enough it was low. So i filled it back up and drove it for about a day and a half checked it again and its low again. My oil level hasn't gone up, so im thinking my head gaskets are pooched. Opinions? Thoughts?
TECH Addict
Joined: Jun 2009
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From: Tulsa, OK
Get a radiator pressure tester, and use it with the engine cold. Don't overpressurize the system, no more pressure than the radiator cap is good for. Check everywhere visually for leaks first. Don't forget to test the radiator cap to using the adapter that comes with the testing kit. You should be able to rent this from O'Reilly or AZ. I'd start with the cap, because it's probably your problem.
Then, when done leave the cap off and start the car and let it fully warm up. Watch the radiator to see if you are getting lots of bubbles in it from combustion gases being forced into the cooling system.
Then, when done leave the cap off and start the car and let it fully warm up. Watch the radiator to see if you are getting lots of bubbles in it from combustion gases being forced into the cooling system.
The coolant is going somewhere. If you don't visually see it then it must be escaping through the cylinders. Take the plugs out and look to see if there are any that look far cleaner than the rest. Usually a blown head gasket results in failure around either the #7 and/or #8 cylinders.
Thread Starter
Teching In
Joined: Aug 2009
Posts: 37
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From: Manitoba, Canada
Great those are the fun plugs to take out
Its definatley not leaking out and leaving puddles anywhere. So far i've had coolant/head gasket problems with this, my truck, and my dirt bike this year
Its definatley not leaking out and leaving puddles anywhere. So far i've had coolant/head gasket problems with this, my truck, and my dirt bike this year 
Registered User
Joined: Apr 2023
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Coolant?? I have an issue I’m wondering if anyone can can help I have a 4.8 and coolant is going somewhere, I went through an entire DEF jug of it in 2 days. Oil isn’t milky and it doesn’t smoke and I used a pressure tester to find a leak can’t find one anywhere. Any help is appreciated
I have an issue I’m wondering if anyone can can help I have a 4.8 and coolant is going somewhere, I went through an entire DEF jug of it in 2 days. Oil isn’t milky and it doesn’t smoke and I used a pressure tester to find a leak can’t find one anywhere. Any help is appreciated
but for me, I used a borescope camera off Amazon and my number 8 cylinder was clean and the other cylinders were dirty.
Do you ever smell coolant? It's pretty noticable so that would be my first question. Leaks can be from many places and they don't always show signs of it on the ground underneath the car. Leak down test will tell you if you have a blown head gasket. You will see bubbles in the radiator during the leakdown for one.
