Mitsubishi 3 cyl diesel head gasket diagnosing help

[Asymair95]

I recently acquired a new to me Toro Groundsmaster with a Mitsubishi 3 cyl diesel in it. It seemed to run fine when I got it, but was obviously in need of regular maintenance and a tune up. I performed all the usual preventative maint, fluids, filters, valve clearance. This also included a coolant change.

After bleeding the fuel system, the engine started and ran fine. The no load rpm was 3100, so I adjusted it up to the book spec of 3200. Everything seemed to running fine.

The next day while doing a final checking of fluid levels, I came upon an unpleasant surprise.



There is a small oil slick inside the radiator. When I bought it there wasn稚 any there, and when I drained it, there wasn稚 any. The engine was running when I picked it up. No exhaust smoke either.



There is no condensation or white cream on the oil cap. Maybe because it wasn稚 run long enough yet?



Nothing odd on the radiator cap. There was a white crusty substance around the inside of the radiator cap neck, but it looked old to me, and possibly some kind of mineral deposits.

So now what? Tear it down? Run it for awhile?

There is no coolant loss that I can tell, and no white smoke from the exhaust. It has only been run about 30 min so far, but I haven稚 started it again since discovering the oil in the coolant.

 

[Eagleview]

Sometimes, when you change the coolant on a machine you have just bought, you flush out the Stop Leak someone has put in the system and you then have trouble . Not all people are honest and up front about the REAL condition of something they are selling .
I would fill the radiator to the very top, while it is idling and watch for constant bubbles . Sometimes this doesn't help because the leak may be straight from a water gallery to a pushrod hole, or from an oil gallery to a water gallery etc and not into a cylinder etc . It may give you an indication tho that the head has never been re tightened from new .
After doing the bubble test, slowly over fill the rad so that the slick is washed out, then go and do some work with it . Check it again after an hour or so .
If it does it again or you see bubbles, slip the head off, taking note of how tight or loose the bolts may be , check the head and the block for cracks,(Up to you to decide if you just do a visual or get a die type crack test kit) check the gasket for obvious tracks , put on a new gasket and torque it to spec . Check to make sure you can re use the headbolts first, some engines you cannot .

 

[wheelbuilder]

You could pressure test the cooling system to see if it leaks back thru into the oil. They also make a kit to check for exhaust into the coolant. I'd do both before I tore into the head gasket.

 

[Asymair95]

I have started the troubleshoot, thank you for the recommendations.

Yesterday, I over filled the radiator with distilled water to get rid of oil slick on top. I then started the engine and watched for bubbles. As the engine warmed up and the thermostat opened, the level dropped just slightly, and then came back up again. Temp stayed around 160. I did not see any bubbles during this process. I put the radiator cap on and drove around for about 30 min.



Today, I went back out and opened the radiator cap and this is what I saw...another oil slick.



I decided to drain the engine oil and look for water...I found none.



Next, I drained the coolant to look for oil...I found none. However, it was a bit dark, but this may be normal, considering the engine has 3500 hours on it.



I then refilled the radiator with 1 cup simple green, and distilled water to clean things out. I ran it for 45 min, and drained the radiator of the simple green mixture. Again, it came out a bit dark, but nothing crazy. In this pic you can see there is little to no smoke exiting the exhaust.

I’m going to refill with distilled water and run again to flush out the simple green. If after that I am still seeing oil I will try the pressure tester. I do not have one, so will need to borrow one or buy one.

Am I going down the right path here?

 

[wheelbuilder]

That seems reasonable to me. There's nothing weeping from the water pump, right ?

 

[Asymair95]

No leaking anywhere.

I drained and refilled with water only and ran it again for 20 min at various power settings. Will wait till tomorrow to check for oil in the coolant. Checking around for a pressure tester now.

 

[thepumpguysc]

Your local Auto Zone rents tools.. or check w/ the local parts houses.. Napa, Pep Boys, ect..
I have NEVER seen a used Grounds Master that was worth the money someone paid for it..
They got rid of it for a reason.. if u know what I mean..
The ones I've had my hands on usually come from golf courses & are ragged out beyond reuse..
I knew of 1 fella that bought 1 running when he went to look at it.. bought it, drove it on his trailer & that's where it lived, until he brought it to me..
Come to find out, it had no compression.. or I should say, very little, not enough to start on its own..
The sneaky sob's had it running when he got there.. {ether, gas rag, towed it.??} & the guy fell for it..& I've seen THAT more than once.

Personally, I would run it until I started seeing coolant in the OIL.. & keep an eye on the temp.. cuz once they're overheated, that's it..

 

[Eagleview]

I am afraid a pressure test wont help you at all . You are wanting to know how OIL IS GETTING INTO your coolant . Pressure testing the COOLANT wont tell you this .
I would say, you have a very slight weep, across from the oil gallery that feeds the rocker gear and that the copper/tin or Silicone seal on the head gasket is the culprit . I would be pulling the head myself, head gaskets are a weak spot on these engines .

3 cyl Diesel Tractor Blown Head Gasket Repair Detailed *Part 1 of 2* - YouTube

Edited to insert youtube link .

 

[Asymair95]

There is a hyd cooler incorporated in the radiator on these. Sounds like I have my work cut out for me. The pressure tester is free to "Rent" from the local auto parts store. I may give that a shot for kicks first.

I pulled the radiator cap this morning after running yesterday and there is a grey oil slick again inside the radiator neck.

It almost doesn't look like oil though, it's kind of a dark grey substance.

The hyd cooler recommendation is intriguing. I sourced a head gasket for $80 online. Will contact my local toro guy for a price too.

 

[Asymair95]

Put the pressure tester on it.



The kit was easy to use. They didn’t have the right size adapter in there, so I used the universal.



Pumped it up to system pressure of 13 psi...and waited...and waited...and waited. No leaking so far. This was with the system cold.
Guess I’m all out of troubleshooting options at this point?

Local Toro place wants $220 for a head gasket.