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Discussion Starter #1
My 7.3 pick up seems to run ok, does not overheat and does not smoke. I barely add anti freeze but my rh head has 0 compression in all of the cylinders. uses a lot of oil,I live in Fl, any idea what it should cost to install new head on my truck and does this sound possible? /2002 7.3 I would also like an idea what it would cost to replace the engine with a used engine? Thanks in advance.
 

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How are you measuring compression? I find it hard to believe it runs fine on 4 cylinders. Maybe the high oil consumption is bad injector o rings .
 

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I agree with jleedog. Although they will run on 4 cylinders, but will not have enough power to do much.
What compression numbers are you getting? You have to pull the glow plugs to check compression.
Have you checked for blow-by thru the oil fill cap? If you can set the cap on upside down and it stays there with the enging running, then your rings are likely fine.
Bad head gaskets are very rare on the 7.3L, and that would typically show up in the coolant reservoir and/or oil pan.
If you truly have low compression on the entire bank (which I doubt), just putting a head on it wouldn't necessarily fix it.
If it comes down to it, you could probably buy a used engine for around $3k.
 

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Discussion Starter #4
Thanks for the reply, I could not believe it either, there was zero compression on all 4, using a really good quality OTC adapter to go in the glow plug hole. I just realized the oring at the bottom of the adapter was missing, will get one and try again. Still have a problem of oil consumption, 1 qt every 200 miles, already put in new alliant o rinings on injectors. no visible oil leaks, stars right up, no smoke, good blow by test, no oil in exhaust, but seems to lack power, but I am not sure as I always had cummins.
Truck is rust free Fl truck, 11 ft utility body with 6 speed and all 2007 front end upgrades, 19.5 tires. Cannot figure out oil use, can injectors leak that much oil internally?
 

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Check the fuel filter for signs of oil. It will appear black.
 

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How clean is your air filter? With a dirty air filter, the turbo will pull air through the crankcase ventilation right along with any oil in its path. I saw this on some of the stationary engines I worked on many years ago. Jleedog is also right. If it's bad enough the fuel itself will be black
 

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Discussion Starter #7
Thanks Oldrebuiltdodge, and Jledog, Air cleaner is new and fuel is clean as I did o rings twice, first with O relies then I was told they were junk so replaced them with Allliant.
 

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Discussion Starter #8
Thanks Oldrebuiltdodge, and Jledog, Air cleaner is new and fuel is clean as I did o rings twice, first with O relies then I was told they were junk so replaced them with Allliant.
Ordered an OTC compression tester will check compression again tomorrow.
 

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How long have you had the oil consumption issue? Did it start before or after injector removal?
 

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Discussion Starter #10
I bought truck about 6 months ago and I finally realized how much oil it used and compared to my Cummins it is very slow, I know it has an 11 ft utility body filled with tools but I love the truck. As soon as I figure the oil consumption problem I will do bigger injectors and turbo. The new compression tester will be here tomorrow and I will let you no the results. Thx again.
 

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There is only a small handful of places the oil could be going. Aquart every 200 miles seems excessive. It is falling on the ground, burning up in the cylinder, being pushed back into the fuel (bad injector o rings). How many miles are on the truck? If it's not smoking bad then it probably isn't burning in the cylinder, but I could be wrong. If you rolled an oring during injector installation oil may be going into the cooling system (would show on degas tank], or in the fuel system which would result in an oily black fuel filter. Maybe your rings are bad. I guess your numbers will confirm that.
 

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Discussion Starter #12
Oil consumption started as soon as I bought truck before Alliant o rings installed. 2nd half of cylinders averaged at 405 psi.
 

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Any updates?
 

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I doubt that will fix the oil consumption unless the problem was bad o rings to begin with in which case new o rings are way cheaper than new injectors.
 

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Discussion Starter #17
Already did o rings twice recently, first time I used rings I bought on Amazon and was told they were junk so I replaced them with Alliant rings that said motorcraft on package, less than 1000 miles on them, did not help. Taking your advice I checked my fuel filter yesterday and it was black after 800 miles. All cab over trucks have gas tank paint delimitation problems that clog fuel filters so I installed an in line 1 quart Napa spin on filter and never had any other problems with tank. Also removed small filters in tank. Just noticed I have a strong vacuum in tank, when I release fuel cap it is very noticeable. May order new Alliant orings and do them again but it is a hard job for me as I am 70 yrs old.
 

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Well it sounds like you have found the oil consumption problem. The o rings are probably torn or rolled when last installed. Inspect the injector cups, they may have a crack in them that is causing the problem as well. Like tearing the oring during the install. Make sure you lubricate the crap out of them when you install them to keep them from rolling. Several good youtube videos on oring and injector install to watch. The vacuum in your tank is odd, you may have a clogged vent line. Try blowing compressed air in the fill line to check. Good luck and keep us posted.
 
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