Head gasket question

[me3]

Hi everyone, my head gasket has blown from the number 2 cylinder out to the exhaust side of the block. There is no coolant in the oil and no leaks just sounds like it is ticking at idle. My question is will it hurt to drive it for a few days until I can change it? I dont know if it will hurt the block or head. I also dont know why it blew, it hasnt over heated and its all stock non intercooled. I havent even pulled any trailers or big hills yet. But it does have 260,000 on it.

Thanks

David

[Richie O]

Will it hurt it?? Don't know. I would not drive it. To expensive.

[dpuckett]

If you see a chunk out of the gasket, park it. But, I drove my 91 with a blown HG 9000mi before I figured out what it was. I had replaced everything I could think of, and was reading some of Bruce Malinson's old articles, and there was something to the effect of "if your big Cummins sounds like a chirping bird under load, it's likely a blown head gasket..." I asked a few people I knew and they said it was rare in the small ones, but possible. I replaced the gasket, and all was well another 40K before I sold it.

The original gaskets are usually good to 250K or so on the nonIC trucks, especially if they have been turned up. The later head gaskets (91.5+) were better quality- "marine" gaskets. They seem to hold a lot longer. Make SURE the head is flat. I've done 2, and had the heads checked. One was arched about .010"; other was flat. There was nothing I could do for the blocks, so I didnt check them. If I dont know, it isnt as bad.....

Dainel

[2stroke]

thats funny i know Bruce Malinson also.

[Greenleaf]

My 1990 just blew the HG. I don't abuse it and it still let loose after 320-plus thousand miles.

It is blowing bubbles into the coolant bottle and pushing the coolant out of the radiator.

Take my advice and replace that old head. You'll be happy you did. Don't forget that if you mag-flux the head, then mill it, then grind the valves, you will have put good money into a head that is known for cracking. That is why the head was changed years and years ago to the current casting.

Besides, your head is most likley cracked anyhow, so investing a couple hundred wouldn'd likely happen.

[Bookshelf]

My 1990 just blew the HG. I don't abuse it and it still let loose after 320-plus thousand miles.

It is blowing bubbles into the coolant bottle and pushing the coolant out of the radiator.

Take my advice and replace that old head. You'll be happy you did. Don't forget that if you mag-flux the head, then mill it, then grind the valves, you will have put good money into a head that is known for cracking. That is why the head was changed years and years ago to the current casting.

Besides, your head is most likley cracked anyhow, so investing a couple hundred wouldn'd likely happen.

Do you think your head is cracked, head gasket is blown, or both? I see people occasionally posting about the 9mm heads cracking, I'm wondering how much of a problem its been for all of the 89-91 trucks. If you turn up a non ic, add a bigger turbo etc and work the truck is it just asking for trouble? Did you ever have any 9mm motors in the bus fleet?

[ford69557ci]

The problem area for cracking was around the injector holes. I ran a head that was cracked around every injector for almost a year at higher boost with no problems. I did finally switch to a head from a 1996 though.

[Greenleaf]

Yes, the cyl head would/will be a problem. They redesigned them for a reason and the new heads will fit any 12 valve. My truck wasn't used to pull anything and I suspect it too will be cracked. I won't waste money on the old style to mill and cut the valves, then port it.

The school buses are the same engine. 9mm heads years ago. 7mm heads up to 98. I replaced a 9mm head only to have the 7mm head split apart too. I was running exagerated fuel/boost levels with this engine. The Allison (auto transmission) let loose after 'bout 2 years of this.

I will tell you, this bus was always the first to arrive at the track/cross-country meets.

May she rest in piece. It somehow turns out she was traded in sporting OEM Dodge engine parts.