Replace Thermostat ??

[HookMaster]

I have a rebuilt 1984 V$ 100hp Commercial that just now started to trigger the alarm when it has run for about 5-10 mins...... It stopped pretty much right away the first time it happened and I have not used it since winter began. I have just recently statred it and while on idle the alarm went off after about the same amount of time. I did not keep running it to see if it would stop sounding and am concerned that it is a bad thermostat ?? How hard is it to replace if I want to do it myself ? Just wanting to save some labor charges if I can............ Thanks......I don't have a manual at this time so looking for an answer........ Don

 

[boobie]

Re: Replace Thermostat ??

Did you ever check to see which cyl bank is setting off the alarm? All you have to do is disconnect one tan wire at a time going to the temp sender on the head and when you shut up the horn that's the bank overheating. You could have thermo probs, blown head gasket or swelled water deflecters in the block. Recommend getting an OEM service manual if you want to work on it yourself.

 

[DargelJohn]

Re: Replace Thermostat ??

First thing I would do is retorque the head bolts. Sometimes you will develop a combustion leak between the cylinders and water jackets. This will prevent the jackets from filling with water, causing an overheat condition.

Thermostats on old V-4's can be challenging (I have a '96 88SPL). The housing contains two, long springs that control the bypass valves and they can be a pain to hold in place while getting that first bolt started. I made a tool to help the housing in place. I took an old pair of water muffs, cut off the loops, rounded the ends on a grinder and slipped pieces of rubber hose over the prongs. You can stick the prongs in the lower cowling and use leverage to hold the thermostat housing in place while getting that first bolt started.

I also find an IR temperature gun very useful. You can check the temp of each bank to see which side has the problem. Harbor Freight has them for cheap$$.

 

[boobie]

Re: Replace Thermostat ??

I made up a couple of studs that I put in the adapter hsg for guides. You just push the hsg in, compress the springs and put the center bolt in to hold the hsg. Remove one stud at a time and install remaining bolts.

 

[HookMaster]

Re: Replace Thermostat ??

Thanks for the replies..................Sounds like I need to take it to the shop that did the re-build and subsequent maint & repairs.........I seem to have trouble changing out a spark plug.....

"BOAT" - Break out another thousand! I'll let you know what they say........

 

[HookMaster]

Re: Replace Thermostat ??

Started her up on the muffs Sunday and ran it for about 15 minuts with no alarm going off. So will launch and give it a test run soon..............