5.3 rear block freeze plugs
03-19-2019, 06:23 PM
#1
Launching!
Thread Starter
5.3 rear block freeze plugs
How hard is it to replace the rear block freeze plugs behind the flywheel? I seem to be having a leak of coolant on my 01 5.3 around that bellhousing area, and it has a new OEM MLS head gasket installed along with good non cracked heads. It is not coming from from any of the side plugs. I've also read that gm coolant tabs have worked for some in these cases. Any feed back would help out a lot! Thanks!
03-20-2019, 05:46 AM
#2
The LS engines do not have Coolant plugs in the rear of the block area like a traditional old school Small Block.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
03-20-2019, 04:33 PM
#3
Launching!
Thread Starter
The LS engines do not have Coolant plugs in the rear of the block area like a traditional old school Small Block.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
You sir are a life saver!!! Thank you so much for this info it basically narrows it down to my problem at hand!
03-21-2019, 08:17 PM
#5
Launching!
Thread Starter
03-21-2019, 08:39 PM
#6
Now to get the right gasket or O-ring... I would have look deep in the stuff I have, but I am suspecting the o-ring style has a deep groove in it around the port.
#12551933 -Coolant tube crossover seal / block off seal plate type
#12602541 -Coolant tube crossover seal / block off seal O-ring type
05-21-2020, 07:36 AM
#7
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The LS engines do not have Coolant plugs in the rear of the block area like a traditional old school Small Block.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
Check the coolant passages on the rear of the heads. There are 2 plugs, one on each head at the rear of the engine.
99-00 have a 4 port system.
01-up use a cross over in the front and 1 plug at the end of each head in the rear.
1 style use an O-ring to seal it the other uses a flat aluminum gasket with rubber impregnated around the port.
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