LB7 broken head bolt

[Claven]

For quite some time now, I have had a problem with my coolant pressuring up and I thought it was leaky injector sleeves, because it start bubbling right after a comlete set injectors were replaced. After letting it bubble for two years it finally got bad and started blowing the coolant out, I sent it to the dealership to reseal the sleeves, but that didn't fix it (on my dime), so I decided to fix it myself, turned out to be a broken head bolt on number 7 hole at the 10 o'clock position, but what I found was that the hole wasn't tapped as deep as the others (about 1/2 inch), the head bolt bottomed out and broke about 3/4 inch above the hole, I'm assuming right from the factory. I put a stud kit in and that stud bottoms out early.

So there is another reason for pressure in the cooling system.

[Mark Rinker]

This is about the 3rd or 4th scenario (including my own) when coolant leaks at the heads started soon after injectors are replaced - but were not injectors themselves.

Can someone suggest WHY this is happening?

[twaddle]

Hi Claven,
I don't know how long you have owned the truck or if the head gasket has been replaced in the past but I would recommend that you shove a screwdriver down into the bolt hole, turn it and see if any crud comes out on the end of the screwdriver. If there is crud on the screwdriver the next thing is to tap out all the holes (this should be done anyway) to ensure that none of the bolts bottom out with oil, water or crud that may be down inside the bolt holes.
Or is there supposed to be a shorter bolt in that hole anyway?

Let us know how you get on with it.

Good luck

Jim

[Claven]

It's all back together and all is good I cleaned and tapped the holes, but that one hole is not as deep as the others, it's exactly the depth of a factory head bolt, the studs I used are slightly longer and thread in deeper except in that hole.

[Kennedy]

Assuming that you replaced the head gasket(s) also?

[Claven]

oh ya, of course, had to machine the head as well.

Now I have a new problem that I could use a little help with, I'm getting a couple of codes, p0090, p0088, p0193,along with limp mode, pointing me to fuel rail pressure, when I check it with the scanner the FRP actual press is reading -3000 mpa (yes minus), and when I rev it up it goes to +26.4 mpa, I'm thinking FRP sensor, Am I going in the right direction? I will be doing the wire tests today, but any help would be appreciated.

[Claven]

It was a lose wire on the back of the fuel pressure regulator. I was seconds away from handing it off to someone else when I found it.