I have a 01 LB7. I have been expiriencing a lot of problems with the coolant system. I will build coolant pressure then blow excessive coolant out the bypass. I have replaced the cap and had the dealer inspect the problem, ofcourse they couldn't come up with a solution. Know that the weather has been getting cold the heater isn't working. Temp gauge goes from 160 to 180 very rapidly and inconsistently. If the the truck sits idleing for any period of time the temp gauge drops to below 160 and has no heat. I have also been getting air bubbles out of the bleeder on the top of the thermostats. The truck has had 125000 miles of abuse, it has also seen some pretty high exhaust temps so i'm wondering if a head gasket problem might be triggering these problems. I have replaced both thermostats, turbo bypass valve, and have replaced the original fan with an electric fan. The dealer said the problems were caused from the electric fan being to small, which i find hard to believe because the truck has never overheated, it just blows out the overfill. Hopefully i'm not the only one who has expirienced this problem. Thanks for any infeed in advance.
no heat!!
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Head gasket, A leak down test will help show this...
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I would almost put some money on the heater core being clogged with Dex crap
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x2 on the head gasket. Mine is all apart right now for the same symptoms. My temps were always just cooler, never jumped much, but everything else was the same. The coolant blowing out the res. is the main giveaway. I've heard that bad injector seats will cause the coolant to come out the res. also, but I dont know if they affect temps any.
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19 Posts
no heat
Well I've had both problems. the head gasket will pressurize the cooling system and when you get to the point of it saying low coolant the truck will run real cold then all of a sudden when your going down the road it will jump over ot hot. Did not notice any unusual noises with head gasket.
With injector cup sleeves you'll have the same pressure in cooling system and get the low coolant light but it seems it'll run cold then jump up but just jump up to operating temp not hot. The thing I noticed is a ticking noise that sounded like a junk lifter and the noise sounds like its coming from the turbo this was an injector sleeve leaking.
Good luck. If you plan on modifying the truck much go ahead and do head gaskets, head studs, and all eight injector sleeves. When installing the injector sleeves put them in one at a time and bolt the injector in the sleeve after you install it do this one by one this will insure the sleeve stays seated, maybe you wont have to have yours apart twice like I did. good luck
Well I've had both problems. the head gasket will pressurize the cooling system and when you get to the point of it saying low coolant the truck will run real cold then all of a sudden when your going down the road it will jump over ot hot. Did not notice any unusual noises with head gasket.
With injector cup sleeves you'll have the same pressure in cooling system and get the low coolant light but it seems it'll run cold then jump up but just jump up to operating temp not hot. The thing I noticed is a ticking noise that sounded like a junk lifter and the noise sounds like its coming from the turbo this was an injector sleeve leaking.
Good luck. If you plan on modifying the truck much go ahead and do head gaskets, head studs, and all eight injector sleeves. When installing the injector sleeves put them in one at a time and bolt the injector in the sleeve after you install it do this one by one this will insure the sleeve stays seated, maybe you wont have to have yours apart twice like I did. good luck
What do you guys figure for time in a head gasket swap. The dealer said 40 hours, there is no was I am going to pay 40 hours at 85 bucks an hour to replace 2 head gaskets. The thing I can't understand is leak by test came back fine, if injector cups are leaking will the leak by test not be acurate.
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45 Posts
Dealing with the dealer
I am fed up with this problem. i took the truck in for injectors because one was leaking and i was having some system pressurizing. the dealer replaced the (8) injectors and one cup seal?? now if he is taking time to replace one why cant he replace the rest. answer from the dealer, warranty only pays for those that come out.....:wtf1:
why not make some extra money while he is in there and try to make sure things are right. now that i have the truck back its worse than before makes a loud ticking/banging noise, blowing coolant, and always pressure on the system.
i took the truck back in because it was blowing a lot of coolant out now. dealers answer after pressure test....water pump.???
i dont understand.....
1. no leak at water pump
2. if it was leaking why is there pressure on the system after sitting for 2 days
3. they want to fix everything else besides what i took in for
Im tired of arguing with the dealer and gm. gm is way more help than the dealer(inside connection), but i dont want to turn the truck in on a new one. when i picked it up i took the service manager out and asked him to feel the rad hose, ohh pressure. yeah i said no leak under on the water pump either. i opened the surge tank cap for him, where does all this air keep coming from?? couldnt think of an intelligent answer, only thing he could muster was ill make a note of that....:banghead: i think that im going to take up gm's offer and have everything fixed and take it back when it still does it.
Allen Chevrolet in Monroe MI
I am fed up with this problem. i took the truck in for injectors because one was leaking and i was having some system pressurizing. the dealer replaced the (8) injectors and one cup seal?? now if he is taking time to replace one why cant he replace the rest. answer from the dealer, warranty only pays for those that come out.....:wtf1:
why not make some extra money while he is in there and try to make sure things are right. now that i have the truck back its worse than before makes a loud ticking/banging noise, blowing coolant, and always pressure on the system.
i took the truck back in because it was blowing a lot of coolant out now. dealers answer after pressure test....water pump.???
i dont understand.....
1. no leak at water pump
2. if it was leaking why is there pressure on the system after sitting for 2 days
3. they want to fix everything else besides what i took in for
Im tired of arguing with the dealer and gm. gm is way more help than the dealer(inside connection), but i dont want to turn the truck in on a new one. when i picked it up i took the service manager out and asked him to feel the rad hose, ohh pressure. yeah i said no leak under on the water pump either. i opened the surge tank cap for him, where does all this air keep coming from?? couldnt think of an intelligent answer, only thing he could muster was ill make a note of that....:banghead: i think that im going to take up gm's offer and have everything fixed and take it back when it still does it.
Allen Chevrolet in Monroe MI
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19 Posts
no heat
the injector sleeves come from gm. they cost about $28.00 a piece. I get them for $20 cause I use to work there. Sometimes you can find some on ebay I've found them on there a couple times and you can save money that way.
It took me about 30 hours of 3-4 hours here and there per day to do head gaskets, studs and replace all the sleeves and I worked in the rain a couple times because I had my garage completely full when I started on it. This was the first time I had ever tore anything apart on a duramax also so I'd say it could be cut down to about 20 hours if you got good at them.
Then it took me another 10 hours or so when I had to tear it back down to put in new injectors, I replaced all eight sleeves again just to be safe.
If you do it yourself just take your time and lay your parts in the order that you take them off on a work bench. I filled up an eight foot long work bench with parts and had stuff on the floor, and shelves also so keep in mind you need some work space. You'll also need a real good quality 12mm and 17mm 12 point sockets 1/2 inch drive for your head bolts and exhaust to turbo bolts. I had to use a big ratchet, swivel, and the 12 mm to break the bolts loose on the back of the turbo. also busted my knuckles a few times.
Good luck, and if your like me when you get done you'll say I hope I never have to work on that engine again. Give me 5 gas motors to completely rebuild before I have to do heads on a duramax again please!
the injector sleeves come from gm. they cost about $28.00 a piece. I get them for $20 cause I use to work there. Sometimes you can find some on ebay I've found them on there a couple times and you can save money that way.
It took me about 30 hours of 3-4 hours here and there per day to do head gaskets, studs and replace all the sleeves and I worked in the rain a couple times because I had my garage completely full when I started on it. This was the first time I had ever tore anything apart on a duramax also so I'd say it could be cut down to about 20 hours if you got good at them.
Then it took me another 10 hours or so when I had to tear it back down to put in new injectors, I replaced all eight sleeves again just to be safe.
If you do it yourself just take your time and lay your parts in the order that you take them off on a work bench. I filled up an eight foot long work bench with parts and had stuff on the floor, and shelves also so keep in mind you need some work space. You'll also need a real good quality 12mm and 17mm 12 point sockets 1/2 inch drive for your head bolts and exhaust to turbo bolts. I had to use a big ratchet, swivel, and the 12 mm to break the bolts loose on the back of the turbo. also busted my knuckles a few times.
Good luck, and if your like me when you get done you'll say I hope I never have to work on that engine again. Give me 5 gas motors to completely rebuild before I have to do heads on a duramax again please!
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94 Posts
I had the same symtoms but my dealer was very good and replaced all 8 injector sleeves and my oil leak too. I am glad to have my truck back. This thread might help.
Good luck,
Seth
http://www.dieselplace.com/forum/showthread.php?t=122854
Good luck,
Seth
http://www.dieselplace.com/forum/showthread.php?t=122854
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19 Posts
no heat
you get it fixed yet?
you get it fixed yet?
making progress
i used to be under nyoutlawz, but i finally have set up my own account. I am the proud owner of the lb7 to posted the now heat problem. i finally have had time to pull the heads off. I found the left headgasket to be blown. I am glad to have found the problem, well at least I hope thats the problem. I am just waiting for parts, hopefully by the weekend she will be up and running. Definatly not somehting that I would want to work on everyday. So far I have nine hours into it, i figure by the time I am done I will have 25 to 30 thats counting all the running around finding parts and talking on the phone. hopefully this will fix my problem
i used to be under nyoutlawz, but i finally have set up my own account. I am the proud owner of the lb7 to posted the now heat problem. i finally have had time to pull the heads off. I found the left headgasket to be blown. I am glad to have found the problem, well at least I hope thats the problem. I am just waiting for parts, hopefully by the weekend she will be up and running. Definatly not somehting that I would want to work on everyday. So far I have nine hours into it, i figure by the time I am done I will have 25 to 30 thats counting all the running around finding parts and talking on the phone. hopefully this will fix my problem
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1,062 Posts
I should be getting mine back this week sometime after getting the head gaskets replaced. They've had it for two weeks so far. The service manager called me and gave me an update. He said he had never seen so many parts come off a motor. I told him that that was ok just as long as there weren't any extras when they put it back together!
heat again
Well I have finally got my truck back together. After discovering a blown headgasket in my lb7 I also discovered that the left head had a noticeable grove around a couple of the combustion chambers. I brought heads to a machine shop and had .003 shaved off both heads. When the engine was apart i did headstuds, injector cups and injectors. I figured having it all apart was bad enough once and didn't want to take it apart again ever. I figured about 30 hours of labor. when i pulled off the heads i left the exhaust and intake manifolds right on the heads. I'm sure it saved quite a bit of time because I didn't have to mess with taking the turbo off. I have been running the truck all week and havn't had any coolant pressure build up and the heat works good again. If anybody has any questions feel free to ask, I have no secrets.
Well I have finally got my truck back together. After discovering a blown headgasket in my lb7 I also discovered that the left head had a noticeable grove around a couple of the combustion chambers. I brought heads to a machine shop and had .003 shaved off both heads. When the engine was apart i did headstuds, injector cups and injectors. I figured having it all apart was bad enough once and didn't want to take it apart again ever. I figured about 30 hours of labor. when i pulled off the heads i left the exhaust and intake manifolds right on the heads. I'm sure it saved quite a bit of time because I didn't have to mess with taking the turbo off. I have been running the truck all week and havn't had any coolant pressure build up and the heat works good again. If anybody has any questions feel free to ask, I have no secrets.
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6,236 Posts
Good on you! I bet it was a pain in the rear, but it is rewarding to accomplish this on your own.
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