Why are both #2 Thermostat bolts frozen and remedy...

[blackmouth]

Hi, Just finished tearing out entire floor/foam/stringer in the 78 olympic and decided to replace thermostats in 91 130TLRP. For some reason both #2 bolts in thermo snapped (second side as careful as possible over the course of 2 days). PB blastered/heated all many times with some light tapping before even trying to turn any. Took the cylinder head covers off (all but those 2 bolts came right out}. Motor has very low hours, and after the covers came off, almost no corrosion. I'm no stranger to stuck bolts, and after giving the studs another day and a 1/2 can of pb blaster/heat treatment, can't get the stub to move(other one has the remnant of #2 square easy out in it and will have to be drilled). Any other suggestions before I get out the drill....thanks tom

[Hamfisted]

I would say use a drill press to make sure you're drilling squarely and centered into the stub. You may find it easier to buy some hi-po heads from HydroTec in the end.

http://www.hydrotecmarine.com/

The HT-8300 set is about $350.


Mike....... Miami, FL

[blackmouth]

Was trying to do it without removing head(or possibly snapping any more bolts. Realized that stock heads are way cheaper than the hours and frustration I have into it already. Did some searching for Hydro Tec and was having some trouble finding them....do you have a ph # or web address?... Do you know if I can just bolt them on or do I need to upgrade anything else....thank you for your reply.....adios tom

[Ken]

Tom,
To keep the new bolts from seizing up on you again, use a quality thread sealer (I use Permatex 14A thread sealer with Teflon) on the bolt threads.
Good luck [img]smile.gif[/img] ,
Ken K

[blackmouth]

Thanks for the help. I realized that new heads could be had for $50.30 from iboats so am praying that the head bolts come out without any issues. After looking at the thermostat gasket, I realized that the #2 bolts were corroded from some leakage around the gasket. thanks for all the help...tom

[Dennisg]

HI I am no stranger either to stuck bolts I have used white vinegar with great success. I keep appling it with a Q tip over the course of a 24 hr period. the acid in the vinegar eates away at the corrosion, down into the threads.
Another product which works extremely good is called Koril. I have seen this product loosen totally corroded bolts on inboard motor mounts, that were 8 years old, in a 24 hour period.
I hope this is a help. good luck, Dennis