3.0 cyl mercruiser thermostat housing

[jedimaster]

Anyone know how much a 3.0l mercruiser thermostat housing costs? I was changing the thermostat and one of the bolts snapped off inside, nothing to put a pair of vice grips on, and I have already gone through about 6 drill bits, only about 1/4" deep, If I can get it deep enough I can re tap a thread, but I think its gonna cost me about 60 bucks in drill bits.

 

[bjcsc]

Re: 3.0 cyl mercruiser thermostat housing

Get a cobalt bit, keep it oiled...it will drill stainless...

 

[Don S]

Re: 3.0 cyl mercruiser thermostat housing

The cost of the thermostat housing depends on which one it is. Got a SN for the engine, even a year may help. Raw water or fresh water cooled? They all aren't the same.
Also, get an Oxy/Act torch an heat around the bolt. The heat will release the corrosion enough so you can pry the housing off the bolt. Then you can use the vise grips to remove the bolt.

 

[jedimaster]

Re: 3.0 cyl mercruiser thermostat housing

the bolt snapped off inside the housing about a 1/4" down the cover came off. no choice but to drill it. I have a torch.
I found an old cobalt bit I hadn't used and was able to drill through it. Tapped it out and ready to roll.
What do you mean by raw water or fresh water? would raw water be salt water?
I use my boat on fresh water lakes and rivers only. its an '88 3.0 mercruiser. too dark to get the serial number. The boat came from another part of the counter I wonder if I have the correct housing?

 

[jedimaster]

Re: 3.0 cyl mercruiser thermostat housing

Ahh ok, I read an article on raw water versus freshwater cooling. Mine is raw water cooling. After reading the article it sure seems a bit scary. Quite honestly I thought inboards were all setup in a freshwater setup, as I thought they had radiators and the lake water was pumped though it noth the entire engine. I was a bit surprised when I found out how the water went through it.
http://www.perfprotech.com/home/fresh-water-cooling-benefits.htm

How much does it cost roughly to install a freshwater system, the internal heat system might be nice to have during early and late season fishing.

 

[jedimaster]

Re: 3.0 cyl mercruiser thermostat housing

Actually I meant to ask, Do you need to fill/prime the engine with water if it is was completly drained of water? If so how is that accomplished?

 

[Don S]

Re: 3.0 cyl mercruiser thermostat housing

Basic rule for adding FWC to an older engine is if it has over 125 hours on it, forget it. Being an 88 your chances of success are slim.
The biggest problem is all the corrosion in the block. It plugs up a VERY expensive heat exchanger on the side that can't be cleaned out without damaging the new heat exchanger.
I have done it for customers with older engines and it's about a 50% success rate with mid to late 90's engines. How lucky do feel with your late 80's engine?

Regarding filling the raw water side of the cooling system on a raw water cooled engine, that is done automatically (By system design) when the engine is running and the raw water pump is pumping water.