Do I dare start this 5.0 or tear it apart?
06-12-2013, 01:44 AM
#1
Thread Starter
Join Date: Jun 2013
Location: CA
Posts: 21
Do I dare start this 5.0 or tear it apart?
I have a 95 GT 5.0 with 210,000 miles that seemed to have blown a head gasket. Got intake manifold off, unbolted exhaust, and discovered the car came equipped with a freeze-plug block heater that had come out on the side of the engine where all the steam was escaping (driver's side)! I put new block heater in, put intake back on, reconnected the cooling system, and the system holds pressure. Seemed like problem solved.
Oh, replaced thermostat because it wasn't opening until 210F
Then I decided to run a compression test:
1 - 75
2 - 110
3 - 65
4 - 80
5 - 135
6 - 122
7 - 80
8 - 75
No evidence of coolant in oil, plugs were all dry.
Before blowing up the cooling system the car ran strong. Engine continued running until I got off the freeway and turned it off. I bought the car with 195,000 miles on it, never did a compression test before this, so I don't know if this is bad rings or evidence the head gaskets are shot. It has been sitting a long time waiting for me to work on it while I drove our spare vehicle, so there may not be much oil on cylinder walls to help compression on worn rings. Part of me wants to just tear it back apart, and part of me wants to put it together and see if it fires up (and them maybe run another compression test).
Advice?
Oh, replaced thermostat because it wasn't opening until 210F
Then I decided to run a compression test:
1 - 75
2 - 110
3 - 65
4 - 80
5 - 135
6 - 122
7 - 80
8 - 75
No evidence of coolant in oil, plugs were all dry.
Before blowing up the cooling system the car ran strong. Engine continued running until I got off the freeway and turned it off. I bought the car with 195,000 miles on it, never did a compression test before this, so I don't know if this is bad rings or evidence the head gaskets are shot. It has been sitting a long time waiting for me to work on it while I drove our spare vehicle, so there may not be much oil on cylinder walls to help compression on worn rings. Part of me wants to just tear it back apart, and part of me wants to put it together and see if it fires up (and them maybe run another compression test).
Advice?
06-12-2013, 07:22 AM
#3
6th Gear Member
Join Date: Mar 2010
Location: Wisconsin
Posts: 5,061
Lol, may the force be with you while you rebuild.
OR
What do you have to do to get it running? If it did sit a long time, then compression will be all over the place with no oil on walls or rings. These motors can take alot of punishment. I'm not proud of this story but I had a 89 F150 with the 302, it blew a rad. hose during a family emergency forcing me to drive 3-4 miles home with no coolant. Motor died pulling into my driveway. Next morning, thinking the worst, I pulled drain plug from oil pan……… nothing came out!!! It got so hot it turned the oil into a grease like jell once it cooled. Changed oil twice, put another 25k on that truck before rust took its toll. That motor really impressed me.
OR
What do you have to do to get it running? If it did sit a long time, then compression will be all over the place with no oil on walls or rings. These motors can take alot of punishment. I'm not proud of this story but I had a 89 F150 with the 302, it blew a rad. hose during a family emergency forcing me to drive 3-4 miles home with no coolant. Motor died pulling into my driveway. Next morning, thinking the worst, I pulled drain plug from oil pan……… nothing came out!!! It got so hot it turned the oil into a grease like jell once it cooled. Changed oil twice, put another 25k on that truck before rust took its toll. That motor really impressed me.
Last edited by 88 orangepeel notch; 06-12-2013 at 07:49 AM.
06-12-2013, 09:53 AM
#4
1st Gear Member
Join Date: Jan 2005
Location: Corryton, TN 37721
Posts: 127
You might try this old trick! Take the plugs back out, and squirt some motor oil into each plug hole. Crank it over about twice to spread the oil around, and redo your compression check!
Good luck!
Larry
Good luck!
Larry
06-12-2013, 10:00 AM
#5
Thread Starter
Join Date: Jun 2013
Location: CA
Posts: 21
How much oil should I put in? I've hear this trick before, but never NEEDED to do it...
The temp gauge hit redline before I shut it down, but not for more than a minute. The engine had very little power at that point, but not sure if that's because of heat, compression, or the fact that steam filled the whole engine compartment and was probably a major component of what went in the intake...
The temp gauge hit redline before I shut it down, but not for more than a minute. The engine had very little power at that point, but not sure if that's because of heat, compression, or the fact that steam filled the whole engine compartment and was probably a major component of what went in the intake...
06-12-2013, 03:29 PM
#6
1st Gear Member
Join Date: Jan 2005
Location: Corryton, TN 37721
Posts: 127
I used a oil can that has the built in pump, and just squeezed in about two pumps in each plug hole. Sounds like you lost the sealing effect of the rings due to getting too hot, and burning the oil off the rings.
06-13-2013, 11:29 PM
#9
Thread Starter
Join Date: Jun 2013
Location: CA
Posts: 21
2 squirts of 10-40 into each cylinder and half a dozen revs:
1. from 75 to 90
2. from 115 to 155
3. from 65 to 75
4. from 80 to 90
5. from 135 to 145
6. from 122 to 135
7. from 80 to 115
8. from 75 same
topped off the radiator, recheck pressurization of the cooling system. Still holds pressure.
put another squirt of oil in #3,4 and 8 redid pressure test:
1. from 90 to 120
2. from 155 to 140 ????
3. from 75 to 90
4. from 90 to 100
5. from 145 to 130
6. from 135 to 130
7. from 115 to 120
8. from 75 to 105
I think I'm even more confused now.... Even though the cooling system holds pressure, wondering if it's leaking water into a couple of the cylinders. I suppose I'll know for sure if/when I pull the heads.
1. from 75 to 90
2. from 115 to 155
3. from 65 to 75
4. from 80 to 90
5. from 135 to 145
6. from 122 to 135
7. from 80 to 115
8. from 75 same
topped off the radiator, recheck pressurization of the cooling system. Still holds pressure.
put another squirt of oil in #3,4 and 8 redid pressure test:
1. from 90 to 120
2. from 155 to 140 ????
3. from 75 to 90
4. from 90 to 100
5. from 145 to 130
6. from 135 to 130
7. from 115 to 120
8. from 75 to 105
I think I'm even more confused now.... Even though the cooling system holds pressure, wondering if it's leaking water into a couple of the cylinders. I suppose I'll know for sure if/when I pull the heads.
06-14-2013, 07:28 AM
#10
6th Gear Member
Join Date: Mar 2010
Location: Wisconsin
Posts: 5,061
How far away are you from just getting it running? Would it be alot of work or just putting exhaust back on? Seems to me that you might just want to put some miles on it if its close to being a runner now. You'd know for sure then, motor smokes, uses coolant, no power etc. I think your headgaskets are ok yet, stock cast iron heads are much more forgiving when overheated compared to aluminum.