Some Comments on Thermostats

[sastanley]

Raymond, Always good to see another C-30 still floating. I am the 2nd owner, but I was 6 years old when my Dad bought #511 new in 1977.

Compared to the condition of your boat in the pictures, it does not appear my father kept my boat in as good condition as you have.., but my wife and I are continually working to put new life back into the old girl!

We really enjoy her, and a successful trip to the Bahamas without flying there (I've done neither) would be a real treat someday.

[Raymond]

I agree with you about our good old boats still floating. Thanks for the compliment on the upkeep. I just wish that I had kept better records. For instance, I can't remember when that thermostat was last replaced and I wasn't keeping a maintenance log back then.

[StephenGwyn]

When did single action thermostat kits start being sold?

I'm having overheating problems with my FWC engine. They are drastically reduced when I clamp off the bypass, which makes me suspect the thermostat. Since the original double-action thermostats are expensive, I was contemplating the use of Don's Thermostat conversion kit: CSTH_01_512.

However it looks like the 1/4" spacer has already been installed on my engine, but by adding longer studs rather than modifiying the thermostat housing.


I bought my boat in 2003.

When did the did the single action thermostat kits start being sold?
Did anybody else sell something like it?

[JOHN COOKSON]

I'm having overheating problems with my FWC engine. They are drastically reduced when I clamp off the bypass, which makes me suspect the thermostat.

Why not remove the thermostat and control the engine temp with a valve on the bypass?
MMI sells a handy dandy "kit" that consists of a restrictor and a ball valve for the bypass hose. Betcha this would solve your overheating problem in a flash.
BTW #1: How long has it been since the last acid flush?
BTW #2: The hose clamps are way too tight. The clamps should leave only a slight impression on the hose. If it doesn't seal with this amount of pressure there is something wrong with the hose and\or the barb.

TRUE GRIT

[StephenGwyn]

Install manual valve, replace hoses, install check valve, do acid flush, I plan to do all of those things.

However I'm also planning to take the thermostat apart, but before I do I'd like to know how long it's going to take to put put it back together. If it's the original style thermostat, it's 150$ for a replacement, or slightly cheaper to add 1/4" spacer and a new style thermostat. And while I don't mind giving money to MMI, I live in Canada and UPS charges a hefty customs brokerage fee, even though marine engine parts made in the US are duty free under NAFTA.
Love MMI, hate UPS. Also, it means the engine is out of action for at least a week while I wait for parts.

But if it already has the 1/4" spacer, it might already have a single action thermstat available locally.

[ndutton]

I think what John is saying is many of us opt to run without a thermostat using the bypass valve to control the temp instead. It's a personal choice.

[BunnyPlanet169]

Guessing (only) from your picture, there is no good reason for that extra part to be there except to accommodate the aftermarket thermostat. MMI offers a kit which also replaces the studs. Looks like that's what you have.

http://www.moyermarine.com/cgi-bin/shopper.cgi?preadd=action&key=CSTH_03.4_241

It's only minutes to remove. A few more to scrape old gaskets. A few more to replace old hoses that won't come cleanly off fittings....

You'll want two new gaskets to replace.

[Beyent]

Holley Tstat etc

I'm back. I want to acknowledge all the excellent advice I received last fall when I asked for help in winterizing my Atomic 4 for the brutally cold Manitoba winters. The detailed advice from “Ed” “edwardc” and from some of the other Afourians was much appreciated.

I am now back with some more questions. My thermostat and housing look very much like pictures shown by Raymond of his thermostat and housing, except that my thermostat is a Holley 3 spring.
I soaked the Tstat in vinegar overnight and scrubbed it with a toothbrush, as advised by Ed .

I read the suggestions by nnstanley and my questions are as follows:

1.Do I soak the Tstat housing in full strength muriatic acid?;
2.In order to flush the water jacket with muriatic acid, do I by just pour it into the head of the engine and then start the engine?;
3.Do I follow the same procedure with the vinegar flushes.

I can't find a thermostat locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat?

I would appreciate hearing responses to my questions.

I appreciated all the advice I received last fall when I posted for assistance. I am impressed not just with the knowledge of the many persons who provide detailed advice but also with the amount of time that is obviously being taken to read the posts, analyze the problem, critique and evaluate the answers given by other Afourians and then provide advice that responds to the questions asked.

[roadnsky]

I'm back.
...my thermostat is a Holley 3 spring.

1.Do I soak the Tstat housing in full strength muriatic acid?;
2.In order to flush the water jacket with muriatic acid, do I by just pour it into the head of the engine and then start the engine?;
3.Do I follow the same procedure with the vinegar flushes.

Welcome back.
As you may already know, you have the holy grail of A4 Thermostats.
See the attached procedure for acid flush.
(you can substitute vinegar if you'd like)
The pic is an example of the "T-Fitting" mentioned in the procedure.

Gaskets, new studs, a new housing, etc are all available here from this site.
Just give Ken a call and he'll walk you thru exactly what you need as well as invaluable advice.

[Beyent]

Thermostat etc questions

In my previous post, I said:

I can't find a thermostat locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat?

I should have read that sentence more carefully. What I meant to say is:

I can't find a thermostat gasket locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat gasket?

Sorry for any confusion.

[ndutton]

Sure, as long as it works. A few considerations though:

• Be careful to avoid slobbering RTV inside the thermostat housing. You don't want it affecting the thermostat nor do you want it dislodging and drifting downstream possibly causing a clog. Frankly, I'm not sure how it can be avoided.
• I'd be less inclined to try this with a pressurized fresh water cooling system.
• You can always make a gasket with stock material from an auto parts store but watch the thickness. Too much will reduce the effectiveness of the double action part that restricts the bypass port at the top of the housing dome.

Many of us will work up a Moyer parts order and throw in spare gaskets for combined shipping.

Regarding a question in your first post, I'd avoid Muriatic acid for the thermostat. Vinegar works fine and is far less aggressive. The Holley three spring thermostat is much sought after and no longer available so treat it like a fine gem.

[wristwister]

Hey folks, my thermostat is kaput (engine runs waaay too cool always, probably stuck open) and I want to install a new one. I've read all about the original double acting Vs single acting with bypass valve, but I'm not sure what's currently installed on my A4. See the pictures below. It sort of looks like I've got that 1/4" spacer, and those fancy nuts look like what are in the Moyer kit. If so, all I need is to order the CSTH_01_510 and OI should be good, right? So, can someone tell from these pics whether this is the case? Thanks

[JOHN COOKSON]

Are You RWC Or FWC?

Why not take the thermostat out and see what is going on? They you can test the thermostat in a pan of heated water to see if it is closing and opening correctly.
If the thermostat is cruded up maybe all you need is to soak the thermostat in vinegar. If the cooling system is full of crud it would be a good time to do an acid flush.

TRUE GRIT

[joe_db]

Take the elbow off too!
Mine was totally plugged with goo and pretty much disabled the thermostat.

[roadnsky]

One a side note, can you tell us what that ducting in front of the manifold is for?