2004 LB7 coolant system over pressurizaton - Chevy and GMC Duramax Diesel Forum
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post #1 of 3 (permalink) Old 07-22-2019, 07:03 PM Thread Starter
Join Date: Jul 2018
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2004 LB7 coolant system over pressurizaton

Hi guys, I've got a 2004 Chevy 2500HD, that is losing coolant. I've found that it seems to be coming out of the overflow of the reservoir. I've been told this is due to a blown head gasket. I've been quoted about $6k to replace the gaskets, send heads to the machine shop, put in ARB studs and check the injectors and put it all back together. The machine shop bill will be about $4000 of the $6k. Plus about $3k for injectors if they need work/replacement. I can only imagine they do since my truck has 330K miles. Also, my engine seems to be leaking oil like all the gaskets are getting eaten from the inside out meaning there is diesel in my oil... I always change my oil when due along with a quality filter, fuel filter, trans fluid drain and fill and filter and lastly the air filter, been doing this for a few years now. But I can see that my front cover is leaking oil pretty bad.

So, sell the truck for $5k? Buy a new one that I can't afford or buy another used one that I'll have to work on in 5 years. Or fix the one I have.

A used decent truck is about $25K.
Just fixing my head gasket problem is about $10K.
or get rebuilt engine https://www.ebay.com/itm/GM-Duramax-...275.c10http:// ($5500), new 100% injectors ($3000), new turbo ($2000), DT750 Allison ($4500) and some other upgrades (I'm looking for advice from you) for around $15K give or take.

What do you guys think?

1956 Ford F100; 1962 Chevy C10; 1962 Thunderbird
1963 Thunderbird; 1977 CJ5; 1977 El Camino
1980 Mercedes 450SLC; 1982 CJ5; 1983 Porsche 944
1991 BMW 850i; 1994 Mercury Cougar XR7
2000 Chevy 2500 (7.4); 2004 Chevy 2500HD (6.6 LB7)
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post #2 of 3 (permalink) Old 08-16-2019, 04:26 PM
Max-D-red-B's Avatar
Join Date: Jul 2019
Posts: 8
i replaced my head gaskets and injectors for about $4000, i did it myself. the overpressurization is probably from head gasket failure or unsealed injector cups, being the cups themselves or the copper washer sealing the injector inside the cups. the fuel in the oil issue is probably the injector or the hardlines connected to it under the valve cover, or the fuel return lines not sealed correctly under the valve covers. i used XDP for the injectors, head gaskets, arp head studs and a few other parts from e-bay. quality products aren't cheap but are worth the investment if you plan on keeping the truck. save up the cash and do it right the first time. you will be glad you did.

i used these guys because i live in virginia... https://www.xtremediesel.com/

Daily: 2004 Silverado 2500HD LB7 CCSB
6 Rough Country lift 35x12.50R20
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post #3 of 3 (permalink) Old 08-16-2019, 04:34 PM
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Join Date: Jul 2019
Posts: 8
oh can't edit the post... also do the valve lash adjustment for the pushrods while you're in there... always use new seals and gaskets, never reuse those pesky under valve cover fuel return line seals, injector copper washers, or o-rings on the injector cups. DON'T FORGET THE RED LOCKTITE ON THE BOTTOM OF THE INJECTOR CUPS!!!

Daily: 2004 Silverado 2500HD LB7 CCSB
6 Rough Country lift 35x12.50R20
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