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failed 'block test'

Old 04-27-2013, 05:09 PM
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Default failed 'block test'

well, today the cooling system was flushed and a new rad cap added. Noticed the water pump is brand new from previous owner. Did the engine 'block test' with a buddy who has a clue - it failed.

I ordered the haynes manual and will be researching here a whole lot more before going further. I don't want to go to the trouble of replacing the head gasket, getting the head machined (or new head) if there could be other major problems lurking.

fun fun

question now is - is it safe to drive at all ? no visible mixing fluids. If I prevent overheat is it safe to drive or should I just park it until I get this worked out ?

cheers
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Old 04-27-2013, 05:30 PM
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What kind of block test failed?
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Old 04-27-2013, 05:39 PM
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a compression test?
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Old 04-27-2013, 05:55 PM
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pretty much the same as this thing http://www.blockchek.com/

got it at napa
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Old 04-27-2013, 06:01 PM
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That's a good one assuming the cooling system is free from all air(bleed system) and all seals(thermostat,water pump,radiator,intake manifold) and hoses are in proper condition.

Just saying......I've seen them give wrong results.
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Old 04-27-2013, 06:09 PM
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Start with a compression test on all cylinders. The compression spec for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.
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Old 04-27-2013, 06:18 PM
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Ok... a compression check I can get done next week when my usual shop opens. But someone else mentioned a leak test. I've never even heard of that one to be honest. How is it better/different? Which should I get done ? Obviously I'm not wanting to spend too much cash lol
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Old 04-27-2013, 06:20 PM
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Originally Posted by randall L View Post
That's a good one assuming the cooling system is free from all air(bleed system) and all seals(thermostat,water pump,radiator,intake manifold) and hoses are in proper condition.

Just saying......I've seen them give wrong results.
Ouch So not your first choice
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Old 04-27-2013, 06:22 PM
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I used a kit from Autozone & it was positive so I go thinking I have a bad head or gasket & it turned out all I needed was a radiator, TS, water pump ect.....

People will also tell you there is NO WAY a head gasket can "leak oil' but my RENIX 4.0 does. There is a reason why but I won't go into that now other than to say there is a passage there for oil seepage usually right above where the dizzy cap is.
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Old 04-27-2013, 06:45 PM
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Originally Posted by EddieForager View Post
Ok... a compression check I can get done next week when my usual shop opens. But someone else mentioned a leak test. I've never even heard of that one to be honest. How is it better/different? Which should I get done ? Obviously I'm not wanting to spend too much cash lol
A compression test is simpler and will cost you less. A leakdown test is more comprehensive and can often tell you more, but will cost a bit more.

I generally start with a compression test as it only takes a half hour and it often tells the story. But your call. Ask the technician at your shop for their opinion.
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Old 05-25-2013, 09:59 AM
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My 88 was over heating, after reading all i could here this is what i did.....
new thermostat, new radiator, new water pump, new res bottle n cap. new hoses.
make SURE YOU BLEED THE AIR OUT OF THE BLOCK!!!!!!
one trick is to jack up the rear end of the truck.
never got hot again.
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