50 miles on new truck and burning coolant.

[bill11012]

I got a 1990 F350 with 129,840 miles. Had no signs of cavitation/blown head gasket and ran great. I fixed all the little stuff and started driving it the next day. I got a load of lumber on the flat bed and headed home. I pulled into my yard and as I was backing up I noticed a coolant smell. I checked and it was starting to smoke white and the over flow was bubbling. One side of the motor has great compression, the other has 240,0,40,90. I put a cooling system tester on and pumped it up, I can hear the leak in the clinder with 0. This is the first time I have torn in to and IDI, any advice? I am going to pull the head,hopefully it is just the gasket. thanks for the help.

[David85]

Unbolt the heads in the reverse order of the torque down sequence (starting from the outer ends moving in to the center to loosen). The idea is to reduce the risk of cracks.

Remove the injector pump and fuel injector lines as one assembly. DO NOT remove the injector pump drive gear or gear housing. Instead, slide the pump backward out from the drive while tilting up at the rear to get everything out.

3 nuts hold the IP to the drive housing from the outsite, and another 3 (12 point 5/16") bolts are exposed after removing the front access cover of the gear housing.

I'm sure others will have more do add.

[tbone91]

Did someone say to back the head bolts out 1/8 turn max each time until they are all loose?

Unless you have super-human strength, you'll need an engine hoist to replace the head. Some say it is easier to remove the engine when removing the heads. I've only done it the "hard" way.

Which side? The back 3? bolts on the passenger side (US) need to be in the head for R&R, the heater core is in the way. I used a rubber band around them as a third hand.

The valley pan (intake gasket) is single use and not cheap. You may want to consider doing both heads while you're at it...

[bill11012]

It is on the passengers side.
How bad is the intake gasket?

If It is not the head gasket but cavitation instead, than what?

I have a good 6.9 block to over bore to 7.3.

A shop would sleeve the 7.3 I have for $1200, I don't have the cash, so the 6.9 over bore is my only choice.

If I have to pull the hole motor apart, can I reuse the old rings? that's $600 bucks for new ones I dint have.

[dyoung14]

im pretty sure its not cavitation cause if it was you wouldnt have those numbers it sounds like you have a blowed head gasket

[bill11012]

that is what I am thinking.

[87crewdually]

I would take advantage of the situation and pull the motor and freshen up the top end. Especially being the passenger side being blown. I've done it both ways, and it is nice in the comfort of a garage to go through and clean and reassemble everything. If it was just the driver-side and the passengerside was done recently before, then I'd do the driverside in the vehicle.
Whatever you choose make sure you have a good engine hoist since the head is about 120 pounds and the engine over 1100. I used a forklift pulling the engine which worked really well.

[bill11012]

The hoist I have will do it, it is rated at 4,000 pounds.

So I should bite the bullet and do both Head gaskets with the motor out?

I just hate to do that with out redoing the rings and rod bearings, but I don't have the cash for that

[87crewdually]

I popped head gaskets and pulled the motor. I replaced seals on the valves and new upper end gaskets and thermostat. Also went and studded the heads since I'm running turbo with a little higher than recommended boost.
Besides while it's out you can clean up the engine bay and detai the engine. So much nicer working on a clean engine.

[bill11012]

If I blew one, the other cant be far behind. I will pull it, then I will do both.

You blow them from too much boost?

That is nice looking IDI! rep sent.

How high does it rev with the 4.56s and C6?

Dont you have a really low top speed?

[87crewdually]

I'm now running 15lbs of boost loaded with my foot in it (not all the time and keeping egt below 1200*). Was running more but unsure of how much because my line for the gauge had a little pinch hole in it. I mostly run 50-55mph at 25-2600rpm with the c-6 and bigger tires (235's)
I'm desperately in the process of trying to get a o/d gearvendor unit and/or 3.55's. I feel the truck has enough power to handle both.
I forgot to mention my engine also only had 140,000 miles when I did the gaskets, which was another reason I left the bottom end alone.

[David85]

4.56 gears with a C6, thats gotta hurt! Could probably rip the nuts off a 747 though.

Only problem with pulling the engine is it becomes a slippery slope. Has a way of turning into a full rebuild. But it is easier to pull it and you know you can do a better job that way. These engines don't leave much room to work around in the truck because they are so huge. It can be done both ways, but its better to pull the engine if you have the tools for it.

Intake manifold gasket.......

The intake manifold gasket isn't really hard on these engines. But its not the same kind of gasket you might be used to with other V8s.

The gasket and the top engine pan (valley pan) are actually the same part, and thats why the "intake manifold gasket" is so expensive to replace (~$50). However, I have heard of guys reusing them as long as they are in good condition and not damage when taken out. RTV sealer or a high performance engine sealer seems to work according to what I've read.

The front and rear of the pan is sealed with only RTV sealer right on the metal.

If you want to start pushing 15 psi of boost, its a good idea to use sealer on them anyway. When I put my engine back together, I used copper spray sealer on the intake gasket as extra insurance. Dave Sponaugle said he managed to blow his valley pan with too much turbo boost. A leak reached the crank case just below the valley pan and the pressure inflated the pan destroying it. Thats where I first heard about this gasket being a weak link for boost pressures well above 10 PSI.

If you have a turbo, or intend to install one eventually, a tip I read on another forum is to knock some extra holes in the drain back baffle of the valley pan. You will see what I am talking about when you take the pan out. In some rare cases, oil drains back from the turbo at a rate faster than the stock drain holes can accommodate. In those rare cases, it can cause the oil to back up and pop out around the grommet resulting in a big mess.

There might have been some underlying problems on that engine, but since it was cheap insurance against that problem, I added some extra holes to mine.

[Dave Sponaugle]

With 0 being on cylinder 3 I am going to guess head gasket and possibly a valve problem.

You will get a much better job on the head gaskets with the engine removed from the truck.
When you install the head, no trace of oil on the head or block deck to contaminate the head gasket.

That will be hard to do with the engine in the truck.

Funny thing, the time factor is almost the same either way.
With a turbo installed, pulling the engine is faster than working on it in the truck.

[tbone91]

Originally Posted by bill11012

You blow them from too much boost?

Head gaskets can also blow from over-filling the crankcase with oil or from not servicing the CDR. When you get the heads off, you will see why. The distance from the top of the pistons to the heads is the thickness of the gasket. You don't want oil droplets going down the intake...

[Dave Sponaugle]

4.56 gears with a C 6 works out to 65 MPH top speed at 3300 RPM.

2800 at 55 MPH.

I second the enlarge the drain holes if you think you will install a turbo later.
The CDR hole will become the oil return for the turbo.