Image of thermostat housing block side?

[BunnyPlanet169]

Beyent: if you don't have one already (and I'm thinking you do not), purchase The Manual from our Forum host MMI. I cannot stress this strongly enough. It is clearly written, well illustrated, and will answer many of your questions. Good for you to learn a new set of skills - I was in the same position not too many years ago.

Do this now, and buy a couple gaskets to slip in with the shipping....

I've only ever tried a gasket goop to make valve cover gaskets, where there's basically no pressure, and no fluid. It leaked. Granted, it was an American Motors product.... Others may have better experience, but there's a reason they make gaskets. Hit your friendly local auto parts store, and buy a sheet of gasket material. Use the housing for a pattern and an exacto knife. Or spend the $3 and wait for your manual to arrive....

DO NOT play around with full strength muriatic acid. Yet. DO NOT play indoors with it either. It fumes and can seriously hurt you - lungs or skin. I emphasize this because your questions are a bit alarming - maybe you know this already.

There are a number of threads on here about flushing.... Search 'vinegar flush'... It's also fully described in the manual. Fully explore vinegar flushing before you attempt muriatic acid. It's a similar technique, without the risk of serious chemical burns.

Why do you want to flush? You were running ok at 160.... You can clean out the housing with a wire brush.

PS: Welcome to the Forum!

[hanleyclifford]

+1 on the dangers of muriatic acid. Whenever I work with it I always make sure I remain upwind of it in a well ventilated area. Even the fumes in small quantity can hurt your eyes and lungs. Be careful.

[sastanley]

Beyent...Welcome to the forum...and I second the MMI manual if you don't have one.

What were the results when you tried full strength VINEGAR on the t-stat??

You've already got lots of info on muratic acid..it is one of those things you definitely wear safety glasses for and use gloves and long sleeves. Even a splash of the acid while pouring into a bucket of water can hassle your skin.



Did we answer all the questions ?

[edwardc]

...Ed, regarding your comments about the route that water takes in an Atomic 4, I have been looking for pictures of an Atomic 4 so that I can trace the path that the raw water takes as it finds its way through the block, to the Tstat, rejoins and goes into and out of the manifold and thus back into the lake but I haven't found any yet. ...

Does this help? (originally posted by rigspelt)

I am now back with some more questions. In a different thread, I noticed pictures posted by Raymond which showed the Tstat housing and Tstat very badly corroded. My case is much the same. ...

If the boss on the inside of the thermostat housing is badly corroded, the bypass cutoff part of the thermostat will never seat against it properly, and no amount of cleaning will fix that. Our host sells an excellent replacement housing that is cast from bronze and will not rust:

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=CSTH&keywords=all&template=Templates/B000_storebuilder.html

[Beyent]

Tstat etc

Thank-you for all the advice from each of you. All my questions and concerns (re the muriatic acid) have been answered. Thank-you for reinforcing my concerns about muriatic acid.

To respond to the questions asked in some of the posts, the vinegar soak of my Holley Tstat and of the Tstat housing did wonders. All the grime and rust is gone and I can now read the name of the manufacturer and state of manufacture of the Holley Tstat.

My boat is going in on May 20 (May 18th is a national holiday) so I don't have the time to wait for the gasket. I will pick up some gasket material at a NAPA store in the meantime and yes, it makes sense to order the gasket when I order the Manual.

Thanks again for all the help.

[Beyent]

Vinegar flushes

One last question. I'll leave the muriatic acid out of the picture for now. If I use vinegar to flush, do I pour it into the head opening where the Tstat is located or do I pump it through the entire engine block.

Ed, the diagram you posted re water movement in the engine is excellent. Thanks.

[ndutton]

No, it is typically pumped through using the engine coolant pump. The thermostat should be removed but the housing reinstalled for this procedure. Close the bypass valve too - or if one is not fitted, pinch the bypass hose with vise grips.

[campbdon]

I am planning to do the vinegar flush too, but Neil, why do you suggest to remove the Tstat? My plan was to get the engine hot then switch the hose from the thruhull to the vinegar (5% acetic acid) , while pinching the bypass hose (as you suggest). Then stop engine and let sit a few days. Repeat.
Would this method get vinegar throughout the block and exhaust?
Thanks
DonC

[ndutton]

I am planning to do the vinegar flush too, but Neil, why do you suggest to remove the Tstat? My plan was to get the engine hot then switch the hose from the thruhull to the vinegar (5% acetic acid) , while pinching the bypass hose (as you suggest). Then stop engine and let sit a few days. Repeat.
Would this method get vinegar throughout the block and exhaust?
Thanks
DonC

The thermostat removal suggestion wasn't really mine. I was simply repeating part of the MMI acid flush procedure, repeated here in its entirety with the pertinent section highlighted:

"Here is the procedure for acid flushing and pressure flushing as taken from our FAQ and service and overhaul manual. You'll find our flushing kit very helpful in performing this essential maintenance task.

ACID FLUSHING: The following acid flush is most effective when used as a preventative maintenance measure every 3 to 5 years:

CAUTION: Be sure to wear proper protective clothing (including eye protection). Always add acid to water when mixing, and if possible, hang a bucket over the exhaust outlet to catch acid solution when discharging from boat.

1) Mix 1/3 gallon of household muriatic acid (30% concentration) into a 5 gallon bucket of water.

2) Draw the entire 5 gallons of acid solution into the engine through an inlet "T" fitting between the raw water through-hull and the inlet to the raw water cooling pump (the same "T" as used for winterizing the engine). For best results, thermostat should be removed and the by-pass hose temporarily clamped off. All the acid solution will then be pumped through the block by running the engine. Stop the engine as soon as the bucket is empty.

NOTE: Some of the acid solution will find its way into the exhaust system, which might loosen up any crud that may have built up within the water lift muffler and connecting plumbing.

3) Start the engine after letting the acid sit in the water jackets for about 15 minutes and run it long enough to thoroughly flush out the acid.

4) If it has been possible to retrieve the acid solution from the back of the exhaust system, add approximately 1/2 pound of household baking soda to five gallons of acid solution prior to discarding."

I clamp off the hose with a pair of vise grips, placing small (2" square) pieces of plywood between the hose and jaws to prevent damage to the hose. If your hose is so stiff that this damages it, it probably needs to be replaced anyway.

Note to always add acid to water, not the other way around (remember what happens if you pour water onto a hot frying pan).

Also, the bypass hose (the one that you want to clamp off) is the one leading INTO the thermostat ( the one on the alternator side of the block), not the hose coming OUT of the thermostat.

[JOHN COOKSON]

HERE'S WHAT I DO

Mix water and muriatic acid* in a five gallon bucket.
Put the water pump inlet hose into another five gallon bucket full of water from the marina water supply. Start the engine and run it until it gets to operating temperature. Supply water to the bucket as needed. The thermostat will be open when the engine gets to operating temperature.
Idle the engine back and close the valve on the bypass forcing all the cooling water through the thermostat.
Put the inlet hose into the bucket of diluted acid. After the acid is aspirated turn the engine off for 15 or so minutes. Then place the inlet hose back into the bucket of water, start the engine, and flush the acid out.
*I like muriatic acid because it's done and over quickly - you don't have to come back later to complete the job.

ex TRUE GRIT