Blown Head Gasket?
#21
Richard Gallant, thanks for that! Looks like the .002 is correct. I'm gonna guess that's the same for the block. For aluminum heads, I usually just send them to a head shop and have them cleaned and the valves seated. If they are warped, then the shop can plane 'em down (if within specs). This truck has about 100k miles on it and I'm pretty sure the heads have been off before. I found a number of missing fasteners when taking it apart and one of the lower intake bolts was extremely loose. It wasn't stripped, so whoever did the heads last time probably forgot to torque that one. Also, I had to replace the radiator as it was full of Bars-Leak... they probably tried that at some point as a repair.
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Richard Gallant (06-10-2022)
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Troy_Less (06-12-2022)
#25
@Troy_Less Bars Stop Leak a tool of the devil surely
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Richard Gallant (06-12-2022)
#26
Okay... checked the heads and the block's deck and all look good. I couldn't find any warpage at all with the .002 feeler gauge. I then used a flashlight and a giant magnifying glass and looked at the heads, block, and old gaskets to see if there was any visible area where combustion gas could conceivably get into the coolant system. I couldn't find anything.
Reman engines are around $6,000, so that's not an option for my buddy. And in my mind, there is not a good argument for putting a 20yr old used engine in the truck. Seems to me it would be more sensible to just go buy another used Disco II that was running. So, the decision has to be made whether to gamble and spend the time (and money) putting the engine back together to see if the problem is gone.
Any advice from the good people on this forum?
Thanks!
Reman engines are around $6,000, so that's not an option for my buddy. And in my mind, there is not a good argument for putting a 20yr old used engine in the truck. Seems to me it would be more sensible to just go buy another used Disco II that was running. So, the decision has to be made whether to gamble and spend the time (and money) putting the engine back together to see if the problem is gone.
Any advice from the good people on this forum?
Thanks!
#27
Given your situation I would pressure test it and if the block passes the pressure test I would put it back together and go with it. I have currently have three personal truck all was over 215,000 Mi on them, all of that head gasket job at least once if not twice in their lives. These engines are amazingly durable if you keep them cool, it took me about 13 or 14 trucks before I realized the inline thermostat mod was the only way to go I know, sometimes I kick myself because I feel like I'm a slow learner but there are still lots a people on this forum that will tell you that a good quality OEM thermostat works just as well as the inline mod and that may be true for a short period Of time but eventually they all quit working properly.
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Troy_Less (06-13-2022)
#28
Given your situation I would pressure test it and if the block passes the pressure test I would put it back together and go with it. I have currently have three personal truck all was over 215,000 Mi on them, all of that head gasket job at least once if not twice in their lives. These engines are amazingly durable if you keep them cool, it took me about 13 or 14 trucks before I realized the inline thermostat mod was the only way to go I know, sometimes I kick myself because I feel like I'm a slow learner but there are still lots a people on this forum that will tell you that a good quality OEM thermostat works just as well as the inline mod and that may be true for a short period Of time but eventually they all quit working properly.
I saw where a guy who had a similar problem pressurized each cylinder via the sparkplug with 120 psi and then waited until one cylinder produced bubbles in the coolant. Would have been good to know this before I pulled the heads off! Though I was almost certain this engine had a blown head gasket due to being way overheated several times... so probably would have pulled the heads anyway. It might be worth it to put the heads back on, torque them down and try pressurizing each cylinder... I could probably build a makeshift clear filler tube for just the heads so I could see if there were any bubbles. Then I wouldn't have to put the intake(s) and ALL THE OTHER STUFF back on to test the engine.
The idea of pressurizing the cylinder is really quite clever I think. The combustion chamber can handle around 1000 psi... so 120psi is nothing. And it'll only allow a tiny amount of air into the coolant channels of the heads... and as there's no cap on the system, whatever leaks will just bubble out so the pressure will never get a chance to build up. May make the valves whistle a bit, but that won't hurt anything.
Any thoughts on this?
Thanks!
#29
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Boos00disco
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04-04-2009 02:24 PM