bigd450

The other day I checked my coolant and noticed a slight trace of oil. Drove about 100km and decided to check it again and it was completely black and the oil was down a liter or two. I was hoping it was the oil cooler but got it tested and it was fine up to 75psi. The weird thing is the truck runs just fine, nice black smoke lots of boost and when its running the coolant lines don't even seem pressurized. I don't have much choice I guess to take the head off and find out but just wondering if there is anything else to check first or what is most likely the problem? So far I have been told its either oil cooler, headgasket or even cracked head or block. Hopefully just the head gasket, then I will o-ring it and put springs in it I guess.

dieselfan

how high of boost have you been running?

S400_12vDiezel

You might have a cracked head but most likely it is a leaking head gasket, my recomendation would be firerings and 12mm studs. If you want to spend the extra money buy the ARP 625's or the Haisley H-11's, both of which are more robust than standard 12mm studs. But standard 12mm studs are just fine for about 90% of the trucks out there...

bigd450

I have been running around 40psi. I will just reuse the Arp studs I got and o-ring the head. If it is just the headgasket. I should find out this weekend I guess.

dieselfan

i thought the hg could take 40psi stock and with studs 50psi?

Ph4tty

Usually but its not law or anything. There are lots of factors.

Mike Holmen

Its mostly from high egt's that kills the head gasket. Have you pressured up the intake side and check for cracks. Do the same on the exhaust. If might be easier to go get a new head, than machining you old head. They get pretty wavey/warped on the head surface and have to get machined to clean up the surface. Then you need a thicker gasket. O-rings are a pain. Good block and head prep would go a long ways. Torque your ARP's up to 135 lb*ft and get some slick 50 (or what ever is the cheapest) for the threads. Do a few re-torque, you should be ok. I bet that you gasket is pretty burnout from the coolant passage/to the oil passage to the cylinder. Head gasket are easy. If you have studs, it slows you down some. Leave on the exhaust manifold and unbolt the four nuts on the turbo. Remove injectors and injector lines. Pull the push rods. There a coolant hole on the side of the block at the front that works well for dumping coolant and saves coolant clean-ups in the cylinders. If your carefull you can leave in the injectors, but don't put it down face down as the nozzle tips stick out some. Most people take apart to much and it turns into a big job, when it really isn't. Remove the air horn. There also one darn fuel fitting at the back of the head thats a fuel drain. Good luck.

Emoneysrt-6

yeah i agree with him..........its actually very easy to do

S400_12vDiezel

Using the old head again is not a problem at all, if you have it pressure tested and it passes then you have the head resurfaced and sink the valves in as much as was taken off the head. And you don't need to run a thicker gasket, machining the head does not affect the compression ratio. Running a thicker gasket will reduce your compression and lose you some low-end power.

bigd450

Thanks for the tips. I guess when I get it off and find out if the head is still good then I will probally be asking for questions like what make and thickness of gasket to use and if I should o-ring it and were to take it too.

dodgediesel

PM me if you need a hand...

bigd450

Thanks for the offer but I did manage to get it out yesterday. Looks like the head gasket is shot still going to the head tested but it should be good. From the pics what would be the likely cause for it to go, just too much boost or high egt's? Also in the pic you can see some bubbling is that normal?

bigd450

All the cylinders and valves look good though. The last two weekends all I have done is work on a Cummins last week was a little more exciting though, installing some twins and studs on my brothers CR. It sure is hard on the gut leaning over all day though.

Clunk

The machinist showed me the rough factory cuts on the head surface...looked like a hurry up job.
He said .0025" cleaned it up fine, reinstalled with a Cummins updated gasket and all well about a year now.

After re-assembly I removed the thermostat, refilled with water and used Cascade dish washer soap to clean out the oil from the cooling system....makes a huge mess but works.
With the engine warmed up, water level down a few inches, radiator cap off and 1800 rpm popcicle stick on the throttle/APPS, I poured in a cup of Cascade then after a few seconds oily foam poured out the radiator then subsided. I poured in another cup and after a few seconds it puked again. I continued this drill until it quit puking after pouring in Cascade. After running an additional 20 minutes, I shut the engine off, disconnected the top radiator hose and stuck a piece of pvc pipe in it so it would overhang past the front of the grill and shoot water/soap/junk into a white bucket where I could see the water gradually clear up, started the engine then stuck the end of the garden hose in the now open radiator inlet and flushed another 15 minutes....cleaned'em up good.

I was hitting 1500F pretty regular when my head gasket coked/cracked, I went hybrid/40psi and get out of it just over 1400F now.
What kind of temperatures were you seeing?

Mike Holmen

You cleaning up the block surface? My last head gasket broke threw that same area into the cylinder and out the back of head gasket. If it wasn't for the o-ring I might have hydrauliced the engine. Do a good block clean-up. How does your head look? Your turbo looks a bit sooty, is it spool-up right? It might be carboned up from some egt's. Mine used to do that when my exhaust manifold was loose or bad seal on the exhaust manifold to the turbo. Of course my truck is always broke, so what do I know Did you get out to the black out? I was too broke to make it out. Looks like a sweet ride. Crank-up the boost and smokem hard. Head gaskets are part of the game. At least its isn't big $$$ to fix. I've done three this year, so far. Of course my ride broke so its only matter of time before I blow another one. Twins are fun