Blown SOHC head gasket *PICS*

[ranger7ltr]

Hey ShelbyGt, any update on your heads at the machine shop?

Well I decided after talking with the machine guy that the heads needed to be broke down, re sealed and the valves reseated. The leak down test showed all but 3 valves failed miserably. The valves were so filled with carbon, that they were not seating at all. I brought the second head in today and he broke it down in front of me and you can see where the gases were bypassing the seal and burning past the valve, not to mention all the carbon buildup. He also said it was a good thing, that the lifters were filled with murky water/oil from the gasket failure and that the water could rust the lifter's internal parts and could cause a lifter to seize if I ran it uncleaned.
Total cost is 260.00 to do both heads.

[/IMG]

I am curious to see what kind of damage the aluminum heads might have seen...I am REALLY hoping there is no cracking...Hopefully just warped a bit... And I am goona bug you for a pic or two of the prepped heads before you reinstall please...

Thanks man...

 

[shelbygt]

ranger7ltr,
Got the heads back they look like brand new. He didn't say if they were warped (only that the evidence of the pattern on the head was obvious that it was slightly warped or the bolts had overstretched) but that they are now flat and ready to go. I will try and get a photo of them this weekend. I have a bunch of parts on the way from Tasca Ford, so it will be next week before I can start reassembly.

 

[shelbygt]

cleaned up and resurfaced right head

 

[ranger7ltr]

Thanks for the pictures...

Those really make me wish I had aluminum heads for the OHV engine I have... Yes I know, no one made aluminum heads for the OHV 4 liter...WAH...

 

[shelbygt]

Well after all this...I fired the truck up tonight only to find......the exact same thing. Sputtering and pulled the number 5 plug only to find fresh new coolant. I am beyond frustrated. If there were any cliffs in Florida, I'd be driving this Explorer off of one tonight! A thousand dollars later and I am back where I started!

 

[2000StreetRod]

Still leaking

Dave, I sympathize with your frustration! All that work and expense and to still have the coolant leak.

From what I've read there are only three possible ways that coolant can enter the combustion chamber: cracked or warped head, leaking head gasket, or cracked block. Past posts on the forum about the SOHC seem to agree with your mechanic's statement that head gasket failure is the most common and block failure is the least likely.

I assume that your mechanic checked for cracks before rebuilding your heads. If I also assume that you installed everything correctly then that only leaves the block as the source of your problem.

The first thing I would do is contact your mechanic to verify he tested the heads for cracks. If the right bank has no coolant leak then the new gaskets you used are probably suitable and your installation process is probably correct.

 

[ranger7ltr]

Man I am really sorry to hear that...

If your engine was just sputtering, I was going to say that you might still have coolant in the exhaust system...

But having found coolant in the cylinder I don't think coolant in the exhaust would revert back up into the cylinder...

I certainly hope your machinist pressure tested your heads before resurfacing them...If that is the case the heads should not be the source of the problem...

Maybe the head gasket blew out at a weak spot in itself? I have had this happen once in the past.. The engine started up and ran well for a few minutes then started missing...No coolant loss but the gasket between 2 cylinders blew out and the rest was history...I R&R the head to find this gasket blowout and pulled the other head off too and returned them and got the complete set from a different vendor and got a refund on the original set...

Damn I hope the block isn't cracked....

Keep us posted...

 

[shelbygt]

Yeah this sucks big time! I can't understand why a cylinder wall would crack without overheating or oil starvation. The head seemed like the obvious culprit. I am going to talk to the machine guy later on today and ask all the above questions.

I was meticulous about getting everything right when reassembling, so I am positive it is not something I did. That and after pulling all the plugs, the same #5 cylinder has coolant in it and all others are dry. I pulled the #5 plug and cranked the engine over and it blew quite a bit of coolant out (engine was cold), so it doesn't look good! It looks as if a used motor is the only option at this point. What is strange is that used 97-00 SOHCs are going for 800-1200 while the 01-04 from Rangers, Mazdas and Explorers are only 400-900 (with less mileage). Why is that? The block and heads look the same, but the upper motor looks different. Aren't the timing components the same from 97-04? I am planning to put all this new stuff stuff I just bought (500-600) on the new motor.

Thanks for the condolences...much appreciated!

 

[bluestream1]

What is strange is that used 97-00 SOHCs are going for 800-1200 while the 01-04 from Rangers, Mazdas and Explorers are only 400-900 (with less mileage). Why is that?

I had had to venture a guess, it would be because the 97-2000 motors are in high demand as replacement engines.

They should have made an exemption for them from the cash-for-clunkers program to provide a good supply of used engines for us explorer owners

 

[shelbygt]

I just spoke the machine shop. He says that he still thinks it unlikely that the block is cracked because I have water mixing into the oil almost immediately and that if the block was cracked it would seep in slowly only after it heated up and mine filled up after running it cold for maybe a minute. He said to remove the head and he will double check it for erosion around the coolant passages. If the cylinder is cracked for 300 bucks he can sleeve it, which would require me to dissemble the motor completely. Once I remove the head, I will go from there..... OH WHAT FUN to being doing this all again!

 

[shelbygt]

I had had to venture a guess, it would be because the 97-2000 motors are in high demand as replacement engines.

They should have made an exemption for them from the cash-for-clunkers program to provide a good supply of used engines for us explorer owners

Yeah I thought the same thing when I saw all those Explorers having their motors disabled, thus screwing us poor folks who needed them! LOL

 

[yellowford]

The engine supports on my engine stand are two inches thick. I purchased four M10-1.50x75 hex cap screws grade 8.8. I wouldn't trust any grade 5 bolts for adequate strength. The bolts were just the right length with a washer inserted at the bolt head.

I don't want to be off topic to the original poster but you just said you didn't want to use grade 5 bolts but thats exactly what you put on there 8.8 metric is the equivalent to a grade 5 where as the 10.9 is the same as a SAE grade 8 bolt.

 

[2000StreetRod]

Bolt strength

I don't want to be off topic to the original poster but you just said you didn't want to use grade 5 bolts but thats exactly what you put on there 8.8 metric is the equivalent to a grade 5 where as the 10.9 is the same as a SAE grade 8 bolt.

You're right! I didn't realize that the strength for metric was different than the strength for SAE. An SAE grade 5 has a minimum tensile strength of 120,000 psi and a metric class 8.8 has a minimum tensile strength of 116,000 psi. I would have been better off with a grade 5! Anyway, they were strong enough to hold the engine on the stand.

 

[2000StreetRod]

Coolant passage erosion

I just spoke the machine shop. He says that he still thinks it unlikely that the block is cracked because I have water mixing into the oil almost immediately and that if the block was cracked it would seep in slowly only after it heated up and mine filled up after running it cold for maybe a minute. He said to remove the head and he will double check it for erosion around the coolant passages. If the cylinder is cracked for 300 bucks he can sleeve it, which would require me to dissemble the motor completely. Once I remove the head, I will go from there..... OH WHAT FUN to being doing this all again!

What's the solution if the problem is coolant passage erosion in the head? My Alfa had an alloy head with a lot of pits from corrosion. They were deeper than could be removed by milling but didn't prevent the head gasket from sealing.

Cast iron blocks can be welded but I doubt a weld would be suitable at the cylinder wall. I had a crack in my E-Type block in the water jacket at the deck but not on the cylinder wall. I had it welded and had no problems with it. Hopefully, the problem is not in the block!

 

[bluestream1]

I just spoke the machine shop. He says that he still thinks it unlikely that the block is cracked because I have water mixing into the oil almost immediately and that if the block was cracked it would seep in slowly only after it heated up and mine filled up after running it cold for maybe a minute. He said to remove the head and he will double check it for erosion around the coolant passages. If the cylinder is cracked for 300 bucks he can sleeve it, which would require me to dissemble the motor completely. Once I remove the head, I will go from there..... OH WHAT FUN to being doing this all again!

That sucks..the only good part is that it usually goes quicker second time around due to the learning curve. And the rusty fasteners have all been dealt with. Seems like an odd problem though...

 

[CDW6212R]

Dale I'm sorry to hear that. The SOHC head gaskets are one of the best by Ford. I hit 270 once and 282 later with no harm to my engine. They are better than OHV 4.0's, which are bad for having head gasket go out.

Look carefully at the valve guides also, I have heard of leaks on replaced guides of a 302 head lately. I forgot much of the details, but the guides often go through water jackets and need special care to install them. So have your guy look all of it over harder this time. Regards,

 

[2000StreetRod]

Coolant leak progress?

Dave, any progress on determining the source of the coolant leak?

Also, did you have any trouble getting the rear cassette to seat properly? I tried to install mine today and there is a plastic tab on the lower part of the traction side that is binding on the head casting. I'll pull it out and try a different approach tomorrow. Did you install the jackshaft rear sprocket, chain and cassette as an assembly or cassette first and then the sprocket and chain?

 

[shelbygt]

Dale, got the head off and took it to the machine shop, they checked it out and said it is all fine. No leaks, no cracks and flat. I got the motor back out and disassembled. I have the #5 piston and rod out to check the whole cylinder for damage. So far, I can see nothing. They are loaning me a honing tool to knock the glaze off of the walls tomorrow to see if any cracks show up. They are all at a loss as to why coolant is entering the cylinder at the rate it is. If nothing shows up, I am going to reassemble the heads and torque it down, block off the water passages, fill the system with water and hope I can look up through the empty cylinder and see where the water is entering.

I actually don't remember the order I put it in. The rear cassette went in with absolutely no problem, but I put it in before the heads were on, so that might be why it was so easy?

 

[2000StreetRod]

Correct gasket?

Is there a possibility that you had a right bank gasket installed on the left bank? I know that there are differences but I think the configuration is identical for the middle cylinder. I believe the main difference is for the timing chain opening. Besides, the leak started before you changed the gaskets.

Did you happen to check for coolant in the cylinder #5 intake and exhaust ports? Maybe there is a crack above one of the valves that drains into the combustion chamber when the valve opens.

 

[shelbygt]

Yeah the Felpro gaskets are labeled left up and right up, so it is near impossible to put them on wrong. The machine shop said they checked for all of that and then filled the head with water and got no leaking. I honed the cylinder today and there are no cracks in the cylinder wall. So this leaves the head area as the problem. I am going to reassemble and torque the heads and then fill the motor with water. I am going to also try and pressurize the system and hope I can see the leaking from the bottom through the empty cylinder. This is crazy!