Hot Rods Thermostat modification

I can answer that!
What you say is true...but we all know there's a big difference between engineered to do something and real world experience. Any more modern computer controlled car/truck I wouldn't mess with. The new cars we have we trade before warranty runs out. But anyone with something older they care about should drill imho. Anyone who has had a stuck closed thermostat can appreciate. A stupid $5 part can cost a fortune in repairs. The holes at least allows flow if it won't open.

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Expensive stuff we care about gets a gauge to monitor what's going on and an operator attentive enough to watch the damn gauge.

 

As Mr. Miller suggests by a "Fail Safe" thermostat from Motor Rad. It senses an overheating problem and locks in the open position, rather then lock closed. The only drawback is that when it locks open, it must be replaced but wouldn't you do that with one that fails in the closed position?

 

I agree 100%, but sometimes I like to watch the road! Overheating can happen so fast, and you may be in middle of nowhere when it happens. Mechanic friend of mine it happened to in his 70 Chevy pu, late at night. He found one tool, a large flatblade screwdriver. He took top hose off, was able to reach down through housing and whack screwdriver handle with a rock which bent stat open so he made it home.

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Usually, if a thermostat is going to stick closed, you are not going to be that far away from where you started out, it will occur within miles of where you started the engine. Once the thermostat is opened and the engine is up to temperature, which again will happen within a few miles, the thermostat is basically out of the picture, it's not going to close and cause the engine to over heat.

 

I have a question about those thermostats that some folks have posted about, that "if they fail, they fail in the open position". How does that happen? I'm trying visualize how the thermostat, in a cold engine, it's closed, and the engine is coming up to temperature, and the thermostat says to itself, "oh shit, I'm about to fail!" and it opens itself up. WTF??? How does this work?

 

Is there really much difference between a stuck closed t-stat, and one with 3, 3/8" holes drilled through it? Or with an open one, for that matter?

 

Yes. I'd much rather have no thermostat than a stuck closed one. A few drilled holes would still allow flow.

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Well here again, if the aim is to drill enough holes in it to prevent overheating, then there's no point to installing it in the first place. Just leave it out. But that isn't recommended either.

 

Well lets see, I spend 4-7 grand on a motor, I think I can spend the $25.00 for a fail safe thermostat and get on with my life.

 

OK, so I looked up "Fail Safe Thermostat" and found this: http://www.motoradusa.com/fail-safe.aspx

Their claim is that, when there is a overheating condition caused by another cooling system component failure, that a standard thermostat will close up, but that their thermostat has a special feature that causes it to lock in the open position.

So I have 2 questions maybe someone can help me with here.

1. Is there any evidence that backs up their claim that a standard thermostat will close up when a cooling system overheats? This is a new one on me, I've never heard this before, and frankly I can't see how this would occur. The thermostat closes due to cold, why would it close when the system overheats?
2. Well, this is a point actually, not so much as a question, but I'm open to being corrected about it. The claims for this thermostat is not to prevent an overheating condition at all, it's to avoid the added complication of a thermostat that fails in the closed position AFTER THERE IS ALREADY AN OVERHEATING CONDITION due to OTHER SYSTEM COMPONENTS or poor condition. And then they say the you HAVE TO CHANGE IT OUT anyway, after this. Please explain to me how this does any good at all?

Maybe I'm dense, OK, I'll admit that, but I'm not getting the advantage of this thermostat. Help me out here guys. Why do YOU use one?

 

I think you read it wrong. Their claim is "when standard thermostats fail", not "when there is a overheating condition caused by another cooling system component failure".

From their web site:
"When standard thermostats fail, they lock in the closed position and prevent coolant flow to the engine, which can possibly cause serious damage to your engine. Fail-Safe has a patented safeguard against overheating damage."

What they are likely alluding to is that normally a failed thermostat will be stuck closed and cause overheating. If a failed thermostat sticks open, most people would simply think their engine warms up slow and not do anything about it.

 

From the site:

"
Fail-Safe thermostats are designed with a unique extra stroke that allows operation in two stages:

Stage 1: Within normal operating temperatures, the Fail-Safe operates the same as any other thermostat.

Stage 2: When overheating is caused by a deteriorating cooling system part, the Fail-Safe has a secondary stroke that activates a precision engineered piston that automatically locks the valve into a wide open position allowing coolant to circulate freely."

If you watch the video on that page, it even opens saying "Don't be stuck on the side of the road, because you engine overheated and your conventional thermostat failed in the closed position". It goes one to explain why their thermostat is better, and it clearly states that when a cooling system overheats DUE TO A DETERIORATING COOLING SYSTEM PART, a conventional thermostat will stick in the closed position, while their thermostat will not do that because of the design. Watch the video.

 

Their video doesn't match their written claims.

Marketing bullshit.

 

Sorry not marketing B.S. My OT 2008 HHR had a factory installed fail-safe fail. It failed in the open position and the engine couldn't get up to temp on a cold start. I wish I had saved the old one to show the non-believers.

 

do what you want, just don't pass bad info along as gospel.

Drilling a hole does somethings for sure.
1 is that it lets air bleed out during filling.
2 it allows unregulated coolant flow and increases warm up times. (Neither of which are necessarily good)

3 It is slightly similar and yet highly different than an internal bypass passage.

 

The marketing bullshit I was referring to is in the video. They need to clearly state that the "deteriorating cooling system part" IS the thermostat, rather than implying that is is any other cooling system part failing and causing the standard thermostat to close.

Marketing is another term for misleading the consumer, giving them just enough obscure information to make them come to a conclusion that isn't necessarily accurate. When someone tells me they are in marketing, I view them in a jaded light.

 

Can you explain why it failed? According to the company, they fail because of an overheating condition in the cooling system. Why did your system over heat?

 

In the drag car we used a restrictor, basically like a thin washer, and wetter water, and electric water pump. With no thermostat the coolant flows too quickly to allow radiator to work properly (is my thought), hence the restrictor.
Drilling a few holes just takes a few minutes, and is better imo than a "foolproof" $25 thermostat.
This has always been my idea (anyone can patent it...please send me 10% royalties!) I love simplicity. In theory a thermostat is supposed to open at it's rated temperature.
This , when working as it should, means motor reaches proper temp.(several have said why). The problem is I have personally had them stick! One as I said a brand new Chevy van...it stuck going home (not at start up...but at about 40 miles). I knew motor was toast...although I shut it off , coasted home when it happened.
I've seen ones stuck shut, I've seen people let it idle and mist everything with cool water. Not sure how long motor lasted.
My Chevy van I should have given back to dealer...sure enough at about 2k miles I had oil in water, water in oil...warped heads.
Now...here's my idea. There are solder mixes (lead/tin ratio, etc.) that melts at different temperatures. So you take an ordinary brass thermostat, and an area is soldered on with low temp solder. Thermostat fails shut...temp raises, melts solder and voila! You have coolant flow.
Remember...10% royalty!

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I think you're missing the entire point of the design of this thermostat. Their webpage is very clear that the part is intended to fail in the open position due to an overheating condition that is caused by other system components (not the thermostat!).

 

@Blues4U The marketing bullshit I am referring to is their claim about a "standard" thermostat failing in the closed position due to some other issue in the cooling system, not their fail-safe one. You and I both agree on that. I think we're done now, right?

The myth about coolant flowing too quickly for adequate cooling has been discussed and debunked repeatedly.

 

I've had more seized thermostats than you could believe!

This is a common problem when we were importing "grey market" cars from Japan. [being a car dealer]
Take a car for a test drive and it is suddenly going from cold to overheating.
Another issue is an "Air lock" in an overheating engine can cause the thermostat to close and the temp gauge will read zero.

In hotrodding or vintage road racing a car can sit for a long time between being used ,so I would recommend spend the extra $$ on a failsafe thermostat [And a good mechanical temp gauge]

In vintage road racing you can cook a $30K engine in 1/2 a lap doing a warm-up or f**k it properly if it doesn't warm up at all.

The failsafe thermostat can be reused if has locked open, all you need to do is pry the latches past the tabs with a screwdriver
But on a high dollar engine I would rather buy another thermostat

 

You've had a thermostat seize in the closed position due to an overheated cooling system? Please, just answer that, all the other stuff you posted is interesting, but really has nothing to do with the question.

 

I have replaced thermostats that were stuck closed causing a overheating problem.

 

It's a damn good thing I didn't know about all this shit, all this stuff that can go wrong, back when I was using the old beast as a daily. 4 way drum brakes w/ a single pot, generator & regulator, points & condenser and the rest of it. And now stuck T-stats as common as AOL disks. Drove it out west to our Very Large Square States more than once, didn't run the greatest but, it never let me down. For prep drove it around the block a couple times, and figured it was time for the Blue Highways.

 

Many of us have. Was it forced stuck in the shut position because of an overheating condition? Or did it just stick for some unknown reason, like poor manufacturing tolerances or materials or old age, etc?

 

I borrowed a friend's off topic camper van a couple years ago for a long trip. On the drive home at night in the mountains we had a very long downhill run. The temp gauge went down to cold, there was no heat output, and when I occasionally had to accelerate the van sputtered and ran like crap.

It turns out the owner had drilled a pile of holes in the thermostat. So under the no-load condition of coasting for miles on a cold night, the engine got completely cold, making it a chilly drive, and screwing up the fuel injection computer.

I have come across several thermostats that have failed open, so far I haven't found one failed in the closed position.

It seems that a "fail safe" type thermostat with an extra system for overheated conditions simply has another way to fail.

 

Car never overheated, I watch gauges in everything. As thermostats do, it up and took a crap while I was driving while the car was at operating temp. My first clue the next morning was the temp gauge didn't work, second was a error code for insufficient engine temp. I could still drive the car as is and no overheating, actually was running on the cold side. Got a new thermostat ( factory fail-safe replacement ) , put it in and good to go. Had to drive it about 4 miles for the temp sensor and gauge to reset itself.

 

Most of the time, I would be replacing a hose that had failed. Because of a bad thermostat or a bad hose?
Who knows what failed first.

My only advice on a thermostat (for anyone that cares) is to always test it before you install it with know accurate test equipment.