Head gasket replacement - how to?

Post your questions or problems you are haviing with your Yanmar tractor here.

Moderator: Aaron

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Mon Jun 25, 2018 12:07 pm

Bad news, I blew a second head gasket yesterday while mowing. The coolant tank was filled with oil and there is oil residue in the radiator. The crankcase oil was low, but it was clear oil (not white/gray). I'm afraid that my head my be warped or cracked. I did not have a machine shop inspect when I had it off for this how-to (my mistake!)

Will post more after pulling the head. Also, I need to invest in a winch for my trailer.

winston
Volunteer Poster
Posts: 5433
Joined: Mon Feb 01, 2010 7:29 am
Location: North East Texas

Re: Head gasket replacement - how to?

Postby winston » Mon Jun 25, 2018 12:11 pm

Oh my! :shock:

Aaron
Site Administrator
Posts: 3256
Joined: Thu Jul 26, 2007 12:39 pm
Location: Iowa Park, TX

Re: Head gasket replacement - how to?

Postby Aaron » Mon Jun 25, 2018 12:19 pm

I didn't see any mention of a re-torque after a hot/cold cycle but we strongly recommend it.

https://www.hoyetractor.com/head-gasket.htm

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Mon Jun 25, 2018 4:40 pm

Think my head may have been warped a little to begin with. It would run warm on hot days, but never boiled over or got into the "red" on the guage. I thought (hoped) it was just a head gasket last year when i did this job the first time. It only had 11 hours on it since replacing the head gasket when it gave out yesterday.

Got to take it back down and do it again. Plan to retorque head after the first heat cycle. But first, need to get the head to a machine shop for evaluation.

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Mon Jun 25, 2018 8:37 pm

Got tractor off the trailer and rolled into my shop. The overflow tank is pretty saturated with old oil, but the radiator coolant inside the radiator looks pretty good (clear red).

Also noticed something else interesting, the middle fuel line connector at the pump was damp with diesel fuel. Wondering now if maybe it wasn't quite tightened down fully and sucked air, causing the engine to not start.

Hosed it down with degreaser so tomorrow I'll be ready to start working on it.

winston
Volunteer Poster
Posts: 5433
Joined: Mon Feb 01, 2010 7:29 am
Location: North East Texas

Re: Head gasket replacement - how to?

Postby winston » Tue Jun 26, 2018 4:46 am

I don't think it would suck air in at that connection. It only sees high pressure at that point.

Norm
Volunteer Poster
Posts: 2965
Joined: Sat Feb 16, 2008 10:08 am
Location: Ft Lauderdale Fla./Trenton Ga.

Re: Head gasket replacement - how to?

Postby Norm » Tue Jun 26, 2018 1:02 pm

You need to start over and relate your exact problem. There are conflicting statements on where oil is and is not. Are you saying the tractor will not start?

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Tue Jun 26, 2018 1:21 pm

Norm wrote:There are conflicting statements on where oil is and is not.


Not really. Oil is along the inside of the coolant overflow tank. I don't see any oil inside the radiator when I open the cap and look in with a flashlight. So what is in the overflow tank skimmed off the top.

You may have also read that I used a power washer to clean the engine. That is because the tractor was used in a very dusty work area a couple weeks ago, and last weekend more dust/debris from bush hogging. I wanted a clean engine to work on. That is why I hosed it down with cleaner (Purple Power if you want the exact brand).

Norm wrote:Are you saying the tractor will not start?


The tractor quit while bush hogging. It sat for around 30 minutes while we towed it near to my trailer. I checked oil level, it looked low, so I added a quart and it was where it should be. I'd changed oil 3 hours ago, so it was still clear. Seeing there was oil in the crank case, I tried starting it to get it on the trailer, and it did - but had very low power and barely made it on the trailer. It acted like it may have had air in the lines, like it was only firing on two of the cylinders. When I got the tractor home, it was cold and would not start again (didn't spend much time trying, seeing what needed to be done).

The oil residue in the overflow tank (above) is why I am pulling the head off to have inspected by a machine shop. I did not have this done when I did the head gasket last year and should have. I had a straight edge and did a visual inspection - it looked good, but I want to have the head inspected by a machine shop that works on heads all the time.

Let me know if you have any other questions.

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Tue Jun 26, 2018 9:41 pm

Ok got the oil drained. No metal flakes or shavings, oil looked real good. Also drained coolant, and it looked just a little murky. Hope to have the head pulled tomorrow night.

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Wed Jun 27, 2018 11:04 am

A few pics showing the discoloration of the coolant overflow tank and coolant inside the radiator. Coolant was new and crystal clear 11 engine hours ago. Not good.

Plan to pull head tonight and drop by machine shop in the morning.

Image

Image
Last edited by agirlandhertractor on Wed Jun 27, 2018 8:14 pm, edited 1 time in total.

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Wed Jun 27, 2018 7:06 pm

Thoughts?

Image

Image

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Wed Jun 27, 2018 7:10 pm

Also,

Image

winston
Volunteer Poster
Posts: 5433
Joined: Mon Feb 01, 2010 7:29 am
Location: North East Texas

Re: Head gasket replacement - how to?

Postby winston » Thu Jun 28, 2018 3:50 am

No doubt leaking between 1 and 2. I would think the mess on top of the pistons is unburned diesel as compression was lost between the cylinders. I can't see the point where it blew into the coolant but it evidently did at some point. You are good with pictures.

agirlandhertractor
Volunteer Poster
Posts: 385
Joined: Tue Mar 09, 2010 5:20 am

Re: Head gasket replacement - how to?

Postby agirlandhertractor » Thu Jun 28, 2018 7:38 am

winston wrote:No doubt leaking between 1 and 2. I would think the mess on top of the pistons is unburned diesel as compression was lost between the cylinders.


It felt like it was losing a little power a little before it stopped running completely. Looks like it was only running on the one cylinder at the very end.

winston wrote: I can't see the point where it blew into the coolant but it evidently did at some point.


Maybe in the lower right (circled red)?

Image

Aaron
Site Administrator
Posts: 3256
Joined: Thu Jul 26, 2007 12:39 pm
Location: Iowa Park, TX

Re: Head gasket replacement - how to?

Postby Aaron » Thu Jun 28, 2018 8:00 am

I'm not really sure how you can get oil into the water from a blown head gasket on these tractors. You, no doubt, have a blown head gasket from the pictures but could there be two problems? Cracked head?

My reasoning: There is no pressured oil passages going through the head gasket- only an oil drain back to the crankcase. The pressurized head lubricant is provided by an external oil pipe. It seems to me that if the oil appeared in the water when you were using the tractor then the coolant would be hot and under some pressure. Any opening between the oil & water passages would cause water to push into the oil - not the other way around. The only place I can think of pressurized oil & coolant being able to mix is through a crack in the head. Unless maybe the oil in the bottle was actually just unburned fuel?


Return to “Tech Support”

Who is online

Users browsing this forum: Google [Bot] and 44 guests