leaking thermostat housing

[hcuff]

Hello everyone,


I am hoping for some help and i'm pretty sure my question is going to sound dumb to guys that are good as mechanics. My 860 has been overheating, not all the time but more recently. I checked the coolant which looked good, then disassembled the thermostat housing looked at the thermostat it looked ok. flushed the system several times until the water was clear then put it all back together. Im not sure i have fixed the problem yet because Ii cant get the thermostat housing to stop leaking when i re attach it and refill. I cleaned both sides well, put silicon over the pitted areas replaced the gasket and added a blue liquid gasket. still it leaks . It looks like its coming out of the bolts. Any advice would be appreciated. Do i need to use like pipe thread to seal the threads and bolts?

 

[davesl708]

If the bolts pass through the block into the water jacket then you will need to apply some sealer to them. Looking at a thermostat will not determine if it is working properly. You will need to put it in a pan of water with a thermometer. Heat the water to boiling and watch the thermometer to determine the temp the thermostat opened. this will tell you if the thermostat is working properly. If the thermostat does not close then you have a bad thermostat as well. An open thermostat will not regulate the temp correctly and the engine will overheat.
Also, test the radiator cap. If it will not hold pressure the temp will go up.

 

[hcuff]

If the bolts pass through the block into the water jacket then you will need to apply some sealer to them. Looking at a thermostat will not determine if it is working properly. You will need to put it in a pan of water with a thermometer. Heat the water to boiling and watch the thermometer to determine the temp the thermostat opened. this will tell you if the thermostat is working properly. If the thermostat does not close then you have a bad thermostat as well. An open thermostat will not regulate the temp correctly and the engine will overheat.
Also, test the radiator cap. If it will not hold pressure the temp will go up.

Ok Ill check the thermostat but how can I tell if the Radiator cap holds pressure.. Also is there a specific pipe thread dope I should use?

 

[hcuff]

Ok thermostat is good i am going to get a new gasket and use use permatex for the bolt threads.. Hopefully tomorrow Ill have it running again

 

[davesl708]

Ok Ill check the thermostat but how can I tell if the Radiator cap holds pressure.. Also is there a specific pipe thread dope I should use?

The easiest way to test the cap is to take it to a auto parts store like Autozone or Advance Auto. They usually will test for free or let you use the tool to test it.

If the bolts do not penetrate the water jacket then there will be no need for the threads to have sealer on them.
The gasket instructions should tell you if you need to add any additional sealer.

 

[crankshaft21]

Sometimes the gaskets are to thin to seal. I have used 2 or 3 gaskets to get it to seal. Be careful to tighten down even on the bolts as not to crack the housing. Like as said before, if its leaking through the bolts, put sealer on them.

 

[3930dave]

For the price of a thermostat, I'd just put a new one in.

If pitting is severe, replace the water outlet gooseneck and/or rebuild the surfaces with a good metal type epoxy (ex. JB Weld, or better).

Make sure the rad is clear of external debris (straw, dirt etc) - blow off and wash the rad down with light pressure air and water.

If the above takes care of leaks, and you still have overheating, it may be an internal rad issue or the water pump impeller may have eroded to the point of not moving much coolant.

Rgds, D.

 

[hcuff]

Ok Thanks Lots of good help here . The surfaces are good I think I think the leaks were coming from the bolts. Ill also get a new radiator cap just to be sure. I will get this done tomorrow and hopefully it will run cool and ill update this post tomorrow.

Thank you all so far

 

[Soundguy]

make sure you get the gasket in correctly. there is a slight lip in there. if the gasket moves a bit, it won't seal on one side.

if the metal is badly pitted, just rub a smear of rtv on both sides, set the gasket and thermostat, then outlet, tighten, then let set.

ps, before all that. make sure the outlet is not warped. it can be overtightened and bend the bolt ears.

if it is warped, it won't seal, you will need to true it up first.

once it is true and on, let the rtv sealer setup for 20-30m, then run it.

 

[hcuff]

make sure you get the gasket in correctly. there is a slight lip in there. if the gasket moves a bit, it won't seal on one side.

if the metal is badly pitted, just rub a smear of rtv on both sides, set the gasket and thermostat, then outlet, tighten, then let set.

ps, before all that. make sure the outlet is not warped. it can be overtightened and bend the bolt ears.

if it is warped, it won't seal, you will need to true it up first.

once it is true and on, let the rtv sealer setup for 20-30m, then run it.

Update I ended up replacing the gasket with a thicker one, also used red high heat rtv on both sides and inside the bolt holes I also added a thread sealant to the threads just in case Hand tightened and let it sit for an hour then tightened all the way down Then i let it sit overnight and filled it up this morning So far so good no leaks I ran the tractor for about 15 minutes at a medium high rpm and she stayed cool. I have some bushhogging to do tomorrow so that will be the real test Thanks to everyone who helped This forum is awesome ..