Blown head gasket or cracked head??

[fireman1749]

Truck started running funny yesterday... started running hot and missing... brought it to autozone plugged it into the computer and said #6 cylinder misfire. Take the plug out today and it was milky brown and wet... water pouring out the exhaust now and some steam

 

[cr_the_machinist]

The 4.0's crack heads more than they blow head gaskets. I had to get my heads replaced on my 4.0 about 6 months ago...... $2750 for a total engine rebuild. All the symptoms I had were.....

- Blowing steam out of the exhaust and it had a funny smell
- Engine would miss at an idle while wait at a stop light
- #3 misfire
- Oil in the coolant
- Very rough idle when first started in the morning

After that repair cost I baby my truck now..... cant afford to do that again.

 

[krugford]

How hot is hot? The only way to tell for sure is to tear it apart. Coolant in the cylinder can come from either a blown head gasket or a cracked head. Prepare for the worst, hope for the best. While its apart, have the heads checked even if they don't look bad. Could be cracked, warped, etc. You doing this work yourself?

 

[427ford]

There was a run of bad head castings (prone to cracking) for the early '94 model year. One of ours failed when the truck was under warrantee. I just happened to notice it when I pulled the dipstick and found 'milkshake'. They had the heads on the shelf and got it done in one day. No problems since.

 

[Ranger44]

The earlier 90-92 heads are the ones that are more prone to crack, but all 4.0 heads have been known to crack. Keep in mind that they are not nearly as prone to cracking as the 2.9.....

There are several companies that sell a HD new casting head. LMC, is one of them. There are a few others off ebay that do too.

 

[fireman1749]

there is no water in the oil... its enough to where it will cause it to miss but not enough to leak into the cylinder... im kinda thinking its the lower intake gasket... im going to start the tear down today so ill keep yall posted... it never got hot enough to hit the H on the gauge... it just got hot and then the thermostat would open and it would go cool again

 

[fireman1749]

Little update... theres actually fuel in the antifreeze which indicates intake gasket

 

[MAKG]

That doesn't make the slightest bit of sense. There is no place where pressurized fuel is in contact with the same gasket as antifreeze. The lower intake does not see pressurized fuel, only air/fuel mixture. And THAT is under vacuum, so it will suck in antifreeze if breached.

Do you mean exhaust in the antifreeze (including unburned hydrocarbons)? That indicates a blown head or head gasket.

 

[RyanD2]

The 4.0's crack heads more than they blow head gaskets. I had to get my heads replaced on my 4.0 about 6 months ago...... $2750 for a total engine rebuild. All the symptoms I had were.....

- Blowing steam out of the exhaust and it had a funny smell
- Engine would miss at an idle while wait at a stop light
- #3 misfire
- Oil in the coolant
- Very rough idle when first started in the morning

After that repair cost I baby my truck now..... cant afford to do that again.

I wish I hadn't read this, aside from oil in the coolant I'm experiencing all the same symptoms.

 

[Bird]

I've seen this happen from both blown head gaskets or cracked heads - pressurizing the suspect cylinder with air like doing a leakdown test can help pinpoint - if air starts bubbling in the cooling system immediately, then it's more than likely a head gasket - a cracked head usually shows up after the engine is run a bit and warmed up. Both problems are the result of overheating - the POS factory gauges will show you the problem well after it's already happened.

Bird

 

[fireman1749]

Its headed to the ford dealer monday its the head gasket

 

[fireman1749]

$1586.16

 

[Giant squid]

I have a 2000 4.0L and i just took the heads off so i could clean the lifters and i saw a huge crack over cylinder 6 inbetween the two valves. So right now i cleaned all the lifters out and cleaned all my gasket sufaces. I want to grab a head from a picknpull but cant find one yet, i may have to buy a remanned set for 450. Fireman you should replace it yourself its a easy fix its just time consuming.
I would never give 1500 up for a gasket

its really easy to assemble/disassemble the 4.0 OHV, give it a shot !!!!

 

[fireman1749]

Well are you in college in your senior year working your ass off haha i had to have it fixed and didnt have the time.... runs like a scalded dog now and i have a 12 mth 12,000 mile warranty

 

[Giant squid]

I got nothing but time on my hands and keep forgeting the rest of the world doesnt, good to hear your rig is back in action