Hey guys-
Think I may have joined the HG club tonight but wanted some second opinions and diagnostic help.

97 12v w/ 180K on the clock. Its had a plate, springs and some timing since about 140K. I don't hammer on it real hard, keep the boost low when its under operating temp ect ect. Spikes around 40psi, holds around 36-38. Never retorqued the factory hg/bolts.

Anyway, I noticed a lack of heat today and a real low coolant temp near the end of a short drive. I didn't think much of it. Got in the truck a few hours later and about 10 miles down the road there was no heat/low temp again. Stopped at a red light and watched the gauge climb all the way to the red. I pulled over right away and popped the hood. There was coolant everywhere under the hood, the over flow tank was full and the entire underside of the truck is coated, all the way back to the mud flaps.

I refilled the truck and got it home. Temp stayed low and the heat was slightly warm at best. There were a lot of bubbles in the radiator when refilling, may have just been displacing air as I'm not sure the t-stat was open.

At the time of the initial stop when it over heated the coolant in the overflow tank looked pretty baby puke-ish (couldn't see anything in the radiator) since I refilled it and drove home the coolant in the radiator looks ever worse. At this point there looks to be no coolant in the oil. I checked about 5 min. after I shut the truck off.

This truck is my DD so time to fix it is limited. I'm looking for some help w ways to accurately diagnose the problem.
Any help would be great, thanks.

 

You already diagnosed it LOL.
It's a typical story.
You can refill and try putting a new rad cap on it....but 99.9% sure you got a popped HG.
It happens sooner or later, just preventative maint on a diesel.
If you have the cash, get another head, get it all ready (machining etc).
They all need a little TLC.
Get all your parts together, good time to change the t-stat too.
A bottoming tap, to run in before your new bolts go in.
I just went thru all of this so I know the feeling LOL.

KO

 

If youre doing all the work of taking the head off, o-rings are relatively cheap while its all apart if you want to do more mods down the road. If you want to stick to your hx35 and 35psi of boost, do some ARP or A1 studs and call it a day.

 

i had the same problem. but when i pulled the head the gasket didnt show any signs. did have to take .10 off my head and then studded it. do you really have to machine the rocker pedistals for the clearence?? i see scheid offers machined valve covers. which i ordered but after looking at them a could have done it myself.

 

ARP shortened the stud length requiring a machining of the rocker pedestals.
A-1 studs are full length and don't require mod to the rockers, but often a tall one requires die grinding the cover.

 

The head is off and will be machined and O-ringed in the week to come. There were a few spots that were suspect but the worst was #6. I've got a set of #60 springs to go in as well if I don't go with some from Diesel Pros. I'll be picking up a 339 gasket this afternoon.

I don't want to machine the rockers pedestals or spend the money on studs. Cured head bolts have held together many a truck with several times my power level. The two big power 12v trucks around here only run studs because they got them for free . I'll stay on top of my re torques from here on out, thats for sure.

 

I spent the money on studs instead of o-rings.

I will repeat kiohio1985's comment to bottom tap all the holes in the block. Amazing amount of junk down there plus if you vented the hg it can really get bad.

 

As far as o-ringing the head is concerned, can any good machine shop do this to a head that has been tested as crack free and good to reuse? I would imagine so, but just wanted to ask as I've never gotten it done or heard the ways to get it done. On 4K governor springs is this the highest rated spring kit you'd want to install in the pump for an on-road, street driven truck?

 

O-rings & fire rings require specialized tools that most machine shops do not have in house