head gasket needing replaced?

Ginormous · Feb 11, 2014

Hi guys,
It looks like I have another problem that may also be contributing to making my tractor being hard to start. I noticed coolant seaping out of the head gasket seam. It's very slow; no puddle under the tractor, just a small number of drops that got the concrete wet plus some drips hanging on the bottom of the crank case bolts. It's very clear that coolant is coming out of that seam (driver's side?) underneath where the thermostart connects to the engine -- I should post a picture for posterity. Is this the classic way a head gasket starts to fail?

G

stormpetrel · Feb 11, 2014

I was told to check for head gasket failure by starting the engine, and after it first starts up to check the radiator overflow bottle for air bubbles coming from the tube inside the bottle.

I have had head gasket failure twice (both times from "operator error") and both times saw bubbles in the overflow bottle upon starting.

Good luck!!

winston1 · Feb 11, 2014

No doubt you have a head gasket leak. I wouldn't call it the classic way, rather Stormpetrels would be the classic way. Head gaskets can leak into different areas. If you do the test Stormpetrel described that will pretty much tell you whether combustion is leaking back into the cooling system. If you don't show bubbles there you might try re-torquing your head bolts. Might possibly stop the outer leak. If you are getting bubbles I would recommend a gasket change.

normde2001 · Feb 11, 2014

Clean the area well, and assure it is a HG leak. Very strange that a HG would seep to the outside and coolant reach the ground without drying from hot engine. Mine has shown a slight coolant discoloration at the head/block seam for 13 years, but have never actually seen coolant.

Ginormous · Feb 11, 2014

I was suspicious a few weeks ago because I found the radiator overflow bottle was empty. I checked the radiator and it was full. I refilled the overflow bottle and cleaned off the side of the block because I had spilled some coolant while filling the bottle and went around wiping things off. When I went out this weekend to push snow, I could see coolant clearly coming from the gasket and streaking down, so it leaked out slowly over time in cold temperatures. The overflow bottle looked about as full as it had been. I think I may have seen some white smoke on startup too, so it's probably leaking inside somewhere too. I will definitely check for bubbles in the overflow bottle the next time I start it up.

Ginormous · Feb 18, 2014

So I finally took a picture. Can someone confirm, is the red arrow pointed at the head gasket seam? This is where I have the antifreeze leaking out. Where are the bolts to tighten this down, is the blue arrow one of them? Anyone know what torque this (and the others) should be at? Thanks!

G

diesel lover · Feb 18, 2014

Unfortunately tightening it may make it worse. You cannot only tighten one side as this could warp the head. A mechanic like myself would not charge a whole lot to change the head gasket on your Yanmar engine as opposed to a car or truck.

Stop leak etc will not help only harm. Any further questions I can surely help you!

winston1 · Feb 18, 2014

Yes, that is the head gasket. Yes that is a head bolt. you have six of them, 3 on each side. Torque is 133 ft lbs + or - 3.6. I doubt you will move it with the torque wrench set at that. However, if you do I don't think you will warp your head. If you do I refuse to be held accountable.

I do doubt torquing it will stop the leak but I sure don't know.

California · Feb 18, 2014

If that engine is designed similar to YM2000 you have to look down into the intake manifold to see the next head bolt.

Ginormous · Feb 18, 2014

California said:
If that engine is designed similar to YM2000 you have to look down into the intake manifold to see the next head bolt.

I was wondering where the other bolts were! So does that mean I need to take off the intake manifold to get to the head bolts? How much stuff can I leave connected to the head when I take it off? I'm wondering what other gaskets I may need and if there are any special tools I need.

diesel lover -- thanks for the advice and encouragement. I split my lawn tractor B&S engine a couple summers ago because there was a gasket around the waist of the engine that was leaking oil. It wasn't too bad, but there were lots of things to remove and later re-attach.

G