Anything else to do when changing a head gasket?

[Topher265]

Wish that were the case. When it happened the first time, we thought it ran out of fuel, but it had 1/4 tank. I filled it up until the bottom of the filter screen was submerged. Also, it didn't used to do anything like that before I did all this work on it.

Well, even though it wasn't directly related I'd still pull the sender just to inspect the pickup line. And we can assume you have bled the lines just to make sure? Life has a funny habit of messing with me by letting other things fail as I fix issues completely unrelated. I'm not trying to send you chasing your tail, just thinking out loud.

 

[Lobanz]

Well, even though it wasn't directly related I'd still pull the sender just to inspect the pickup line. And we can assume you have bled the lines just to make sure? Life has a funny habit of messing with me by letting other things fail as I fix issues completely unrelated. I'm not trying to send you chasing your tail, just thinking out loud.

I called the diesel shop and they suggested about the same thing. Check from fuel pickup line on. He said it sounds like air is getting in there or maybe never got out good enough. He said these little engines use so little fuel that it can be hard to get the air out. His words were: "It's kinda like milkin' a mouse." Little piece of trash can get on the intake and block it, and then after the engine runs out of fuel and dies, that vacuum is released and it will start and run fine. Then it will suck it back on there. They found lots of stuff in fuel tanks: walmart bags, shop rags, etc. He said that one time they found a condom in a school bus' fuel tank that was doing this.

 

[Coyote machine]

Also, what's condition/age of air filter?

 

[Lobanz]

Also, what's condition/age of air filter?

Couple years old. Blew it out too and cleaned the housing it goes in. It needed cleaning, but I've seen much worse ones.

Can't do it tonight, but I'm gonna replace the fuel filter and check the fuel tank for trash. And crack the injector caps and see if I can get any air to come through.

Diesel shop suggested that I disconnect fuel line to the banjo on the injector pump and connect a clean fuel line or tube and gravity feed it and see if it still happens. That way I know there's no problem between the pump and the tank pickup line.

There IS a little electric fuel pump -- tank is under the seat.

 

[MinnesotaEric]

Well, did some mowing yesterday. Didn't go well. Didn't seem to have an overheating problem though -- IF we go by the temperatures (as measured from an infrared thermometer pointed at radiator by the upper radiator hose, which has been shown to be within a couple of degrees from actual coolant temp as measured with a thermocouple on a Fluke meter). The temp did get to about 216, but if we didn't cut grass as fast (i.e., let load), they would stay in the 195-208 range. I have not been able to get a good feel for what acceptable temp ranges are, but from the fuzzy indication I have got from reading, this seems OK. Seems like they should definitely be > 180 (the thermostat opening temp) and >220 is getting kinda hot. 230 means something went wrong and you need to let it cool off and shut it down. (Can someone tell me if these temp ranges are OK?) I looked at the coolant level this morning ant it was normal. So, no boiling over. Prior to head gasket fix, the coolant level would have been quite low and I would have to add some. So, I think the temp gauge/sensor is just reading kind of higher than it should be.

BUT...

It started doing something different. It would act like it was running out of fuel or something. But it wasn't. It started running very rough, like it was only running on 1 cylinder or something, and then it would stall out and stop. Thought it might just be some air still in fuel system, but I don't think so. Started doing this often. Got some video of it, but don't have it handy at the moment. This morning, cold, it started right up and ran normally for maybe 60 sec, then it did the same thing. Started again and it didn't stall out, but would periodically run rough and then recover. But it was acting intermittently. Does not seem to smoke when it does this. Injectors have been rebuilt by diesel shop with good reputation. Didn't drop them or anything. I have not messed with the injector pump at all. I did remove the hard lines when doing the head. I did remove and clean the fuel filter -- didn't seem dirty enough to replace (cleaned in kerosene and blew off with air). I did bleed the fuel system afterward (fuel bowl, line to pump, caps on injectors).

Any ideas?

It sort of seems to me that the cooling system is right on the edge of being insufficient. This Kubota engine is a 14 HP engine with a 2.2 QUART coolant capacity. The Yanmar is a 19 HP engine with a 1.1 GAL coolant capacity (about twice as much coolant). Yanmar radiator seems quite a bit bigger too, but haven't measured.

I would like to do the pressure test that Eric talked about. Don't have a pressure tester though. Maybe Advance Auto has one I can rent. I did notice that coolant flows EASILY out the temp sensor hole in the head. Found this out by accident by trying to add coolant with temp sensor out. And the temp sensor is on opposite side of head from the water pump.

I don't know the average specs for diesel engine off the top of my head but a gassers engines kick on electric cooling fans in the 210-220 range and kick off the cooling fans at 180ish to 200 degrees. New CAT diesels warn at 215 degrees and auto shut down at 225. In other words, 225 seems hot.

 

[Coyote machine]

Water boils at 212* F at atmospheric pressure. Coolant mixed with correct amount of distilled water boils at ? under pressure...
Your small fuel pump may want to be put to the test too, as to whether it might be cutting out electrically, possible supplying varied/intermittent fuel delivery/pressure to your fuel system, resulting in the symptoms you describe.
This is another instance of rule out the causal factors to solve the issue.

 

[Topher265]

I don't know the average specs for diesel engine off the top of my head but a gassers engines kick on electric cooling fans in the 210-220 range and kick off the cooling fans at 180ish to 200 degrees. New CAT diesels warn at 215 degrees and auto shut down at 225. In other words, 225 seems hot.

Diesels and gasoline engines in general have the same temperature specs for overheating. Basically, at 210+ I'd be concerned and at 230 damage can occur. Of course, cast iron blocks/heads for either fuel system are more resistant to warping, but not impervious. Diesel engine blocks themselves are also inherently more resistant to warping as well, due to the reinforced nature of the block designs.

Water boils at 212* F at atmospheric pressure. Coolant mixed with correct amount of distilled water boils at ? under pressure...
Your small fuel pump may want to be put to the test too, as to whether it might be cutting out electrically, possible supplying varied/intermittent fuel delivery/pressure to your fuel system, resulting in the symptoms you describe.
This is another instance of rule out the causal factors to solve the issue.

50/50 mixed coolant/water would boil at 265 degrees F with a 15lb cap at sea level.

Good idea with testing the lift pump...maybe it's not supplying the minimum psi or flow rate to the IP.

 

[Lobanz]

Some eeenteresting discoveries.... First is that the stalling out only seems to happen when under load. Could not make it happen just sitting in garage. Will act OK with mower blades engaged but I can tell that its on the verge of stalling. If I start mowing I don't get very far until it wants to stall out. If I remove the load by disengaging the mower blades it will recover to a steady run.

So I took the fuel line off the injector pump and turned the key on to start the electric fuel pump. VERY weak looking stream. Took several seconds to just fill up the fuel line so that any came out. Then just barely a dribble -- like its got severe prostate problems. Same thing on the line going into the fuel filter. Didn't have any line to rig up a gravity feed directly to the injection pump so I traced the fuel lines back to the tank. Found the fuel pump and, lo and behold, there was another inline filter between the tank and the fuel pump. But of course there would be. Just makes good sense. I bet he's clogged up. But I think I'm gonna get some line and bypass him just to make sure. Then I can get everything in one order.

Thoughts?

 

[Coyote machine]

If you're lucky it's just the filter you found that is causing the problem. One step at a time. I have to wonder how she ran at all before?!

 

[Lobanz]

If you're lucky it's just the filter you found that is causing the problem. One step at a time. I have to wonder how she ran at all before?!

I wonder if that can cause the tractor to run lean. Seems like it stalls either because its too lean or sucking air. Can running lean make it run hot?