RTV900 Thermostat housing

[rjglenn]

I did a search, but it's kind of hard to sort through 1828 results so here goes...

I have two RTVs, one I bought new and one with a bad engine that was given to me. The one I bought has a transmission/rear differential problem and since I'm more comfortable with engine work I decided to repair the engine on the one I was given and swap some other parts so I would have one operational machine.

I pulled the head and found a damaged piston and a bent rod, along with a cracked head so I pulled the replacement parts from the other machine. Long story short I got it all back together yesterday and cranked the engine and it ran great, except for a major water leak. Apparently the previous owner had not kept antifreeze in the cooling system and the thermostat housing has a crack in it. The problem is I cannot get the right hand bolt out, the head goes up against the water pump housing that is part of the front cover of the engine.

I don't want to pull the head. That's more time that I don't want to spend not to mention another $70 for a head gasket. Anyone have any suggestions?

 

[Toolguy]

A picture would help. Should not need to pull the head just to change a thermostat.

 

[rjglenn]

Thanks for your reply. I can't post a picture until tomorrow. Sadly this is not a simple thermostat replacement, it is the housing that the thermostat goes in. It mounts to the front of the cylinder head behind the waterpump housing and one of the 3 bolts that holds the housing to the head cannot back out enough because it hits the water pump housing. The water pump housing is a part of the front cover of the engine and cannot reasonably be removed either.

 

[rjglenn]

Never did post a pic, not sure how...

Okay, I fixed it and I did not have to remove the head. I bought a new gasket from Kubota for $1.80. I took a hammer and chisel and broke the old housing at the bolt hole. Then I took a hacksaw and cut the head off of the old bolt and used a pair of needle nose pliers to remove the old bolt. I took an identical sized bolt and put a nut on it and then using a grinder I ground off enough of the bolt so that it would fit into the space between the front of the head and the rear of the water pump housing. Once the bolt was short enough I took the nut off to "fix" the threads from the grinding. I then put the new bolt into the appropriate bolt hole and then placed the gasket onto the bold and slid it into place. I lined up the other bolts and threaded them into the head but did not tighten them down. After this I used a flat blade screw driver to push the bolt against it's hole and then got it to start and tightened it down. I think its being held by 4 or 5 threads but it tightened and once the others were tight it does not leak.

Kind of a piss-poor design but I'm glad I was able to make this repair without having to pull the head.

All in all the job was a success, I just wonder how long it's going to stay together since I replaced a piston & rod from another engine - but I did use the same bearings so maybe I'm good...

 

[Toolguy]

Now that is my kind of a fix. Congratulations on your ingenuity. A lot of guys are afraid to try anything out of the ordinary. Sounds like it will work just fine.

 

[texasjohn]

Congrats on the fix...Now, what is the problem with transmission/differential on the other RTV...sounds to me like you likely have the skill to fix that as well given time...