Blown Head Gasket

[3RRL]

Not entirely true. Yes, water is essentially not compressible. But but opened valves permit water to be pushed out.

Hi Greg,
Normally, before valve opening, the gases would start to compress.
I think what Dave was referring to is if the cylinder is full or near full of water/liquid. It is conceivable that the compression stroke prior to valve opening will lock the engine OR cause damage to components and gaskets...perhaps both?

 

[Diamondpilot]

You are right, it may not crank or blow or bend something. My sister-n-laws 4 cylinder Dodge car once would not crank or start. She had her boyfriend put a new battery in with the same results. She had it towed to my house and when I took the spark plugs out the cylinders were full of gas. I mean to the top of some of the cylinders. The oil pan was also full of over 2 gallons of gas. Not sure what happened but dried it out changed the oil and it fired and ran fine after a little smoke. The only thing we could figure was the low battery voltage made the computer do strange things and one the injectors and make them stay open.

Chris

Chris

 

[greg_g]

Hi Greg,
Normally, before valve opening, the gases would start to compress.
I think what Dave was referring to is if the cylinder is full or near full of water/liquid. It is conceivable that the compression stroke prior to valve opening will lock the engine OR cause damage to components and gaskets...perhaps both?

It is conceivable, but not under the symptoms I described above. I've been through this before, and described symptoms I have personally witnessed. The head gasket being replaced was a sodden mess. Coolant was clearly standing on the top of piston #4. When #4 would compress, coolant was pushed into the head gasket and out the exhaust valves of adjacent cylinders as they opened. That accounts for the watery gray oil spray I described above.

In that particular case, no damage was done to any engine components - because the leaky head gasket itself formed a (messy but safe) release path for the coolant that had accumulated on the compressing cylinder(s).

//greg//

 

[Jinma284]

We did use a torque wrench to tighten head bolts. Greg, go ahead and send me the spec's. I had them at my office but retired on 1/3/08 and I will have to go through a number of boxes to locate them. I should find out today if the head is cracked. If not the machine shop will clean it up and return to me. The gaskets should be here tomorrow from Affordable. Has anyone had a head ground with the stainless steel inserts? Mine dosen't need it but I just wondered. Pat

 

[Dave_Lilly]

What I meant by water being incompressible is that you don't need a cylinder full or near full of water. As long as there is enough water in a cylinder under compression, you only need a tad more volume of water in the cylinder under full compression (valves closed) that would normally be occupied by the air\fuel mixture to blow a head gasket. I have seen this happen in gasoline engines where the compression level is a lot less than the compression level in a diesel. Normally the weakest point in a head gasket is between cylinders so the engine compression blows the water through to the adjacent cylinder which usually is on the exhaust stroke which pushes the water out of the cylinder into the exhaust pipe. When this happens you will get white smoke coming out of the exhaust pipe. The white smoke is steam generated by the water being vaporized by the heat in the adjacent cylinder.
On occasion the head gasket will blow out the side of the head gasket, which should show up as water being blown into the engine compartment.

 

[RobJ]

you only need a tad more volume of water in the cylinder under full compression (valves closed) that would normally be occupied by the air\fuel mixture to blow a head gasket.

Just a tad more water would just raise the compression a bit. The air will still compress. I've started a few with a tad of water in the cylinder, but not full of water. Yeah that can be messy to.

I worked on a oil field pipe tester once. Pump, water, high pressure, etc. Lucky enough to see a pipe go. Just a water mess(the machine has a cab) but the split looks like a slo-mo film.

 

[RonMar]

Just a tad more water would just raise the compression a bit. The air will still compress. I've started a few with a tad of water in the cylinder, but not full of water. Yeah that can be messy to.

I worked on a oil field pipe tester once. Pump, water, high pressure, etc. Lucky enough to see a pipe go. Just a water mess(the machine has a cab) but the split looks like a slo-mo film.

That is why they hydro test pipes and hoses with water. Just a mess and no-one dies from shrpnel...

 

[Jinma284]

Got word late today that the head is not cracked. Will get it back in the next couple days and put it back together with a new thermostat. Will watch temp very close. Don't have any heavy work for it to do. Just pull a 200 gallon spray rig and run the pump with the pto. Other than a bad thermostat I don't understand this. It was not over worked or over reved and would stay at 80 on the temp gage. That is other than about once every third time I started it when within a couple minutes it would over heat. I could shut down for a couple minutes and restart and the temp would stay at 80 for an hour or until I would shut it down. Then all of a sudden one day using the box blade, not abusing then either, after about an hour of work it overheated and blew the head gasket before I noticed. The last time I started it, to pull it in the garage to tear down, it was hard to start and blew out greyish water that made spots all over the hood. It blew out the side of no 3 but it had coolant in 2 and 3. I'll let you know how it goes.

Pat

 

[greg_g]

Thin gray stuff is watery oil (or oily water, depending upon your perspective). You're going to find a soggy head gasket, and water sitting on top of at least one piston head.

Did you ever flush the cooling system since buying the tractor? The blocks in my two Jinmas were positively filthy inside. I had to flush both at least three times before I got clean water to finally come out. And I forget, have you removed the radiator yet - to inspect for and remove blockage through the cooling fins?

//greg//

 

[Eagleview]

We replaced the gasket with no problems. Also replaced the thermostat. Unloaded it off the trailor and started driving. Within 20 seconds it the temp was almost at 100. I shut it down for about 2 minutes and restarted. Temp gage stayed at 80. I work it about 3 times per week. About once per week for the first month it would repeat the heating problem immediately after starting. Shut it off and restart and everything would be fine. About a week ago after running about one hour with a box blade it overheated without me seeing it in time. Blew the head gasket again. Could this be anything other than a defective thermostat?

Its hard to diagnose something without seeing it but it could be the water pump impeller is freewheeling on the pump shaft . Which will cause intermittent water flow . I have seen this before with composite impellers . Take the fan belt off and the hoses at the pump . If you can see the impeller try and hold it while you turn the fan a little . This will rule out this possibility , also check the bottom hose is not sucking flat at higher engine revs , i have seen this happen many times . Both these things will make the water boil in the block and not be imediately apparent because the water in the radiator will be cooler as it is not flowing through the engine . This could be giving you the erratic gauge readings . While were on the subject a point many people do'nt know and it may help someone is that a temperature sender unit needs to be fully imersed in water to work . If the water suddenly drops away by say a blown bottom hose you can cook the engine without the sender even registering an overheat situation .